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Santos Ltd | Varanus Island Compression and Power Optimisation Project – Works Approval Supporting Document of 82

Rev Rev Date Author / Editor Amendment

A 30/08/2019 B Hirniak Issued for internal review

0 17/09/2019 N Phillips Issued to DWER for assessment


Contents

1 Introduction 6

1.1 Overview 6

1.2 Purpose of this Document 6

1.3 Proponent 9

1.4 Premises Description 9

1.5 Project History 10

1.6 Scope of this Works Approval Application 12

1.7 Abbreviations and Acronyms 16

2 Existing Varanus Island Licences and Environmental Approvals 18

2.1 Leases 18

2.2 Environmental Approvals 18

2.3 Assessable Works 19

3 Existing Environment 20

3.1 Climate 20

3.2 Geomorphology 20

3.3 Groundwater 20

3.4 Surface Water 21

3.5 Vegetation and Flora 21

3.6 EPBC Act-listed Species 23

3.7 Terrestrial, Avian and Subterranean Fauna 25

3.8 Noise 33

3.9 Artificial Lighting 33

3.10 Conservation Reserves 33

4 Project Description 35

4.1 Varanus Island Compression and Power Optimisation Project (VICPOP) Overview 35

4.2 Gas processing and Equipment Overview 35

4.3 Condensate Processing 38

4.4 Existing and Additional VICPOP Utilities 38

4.5 Supporting Infrastructure and Services 40

4.6 Pre-commissioning and Commissioning Activities 43

4.7 VICPOP Work Phases and Timing 43

5 Stakeholder Consultation 44

5.1 Santos WA Stakeholder Consultation Strategy 44

5.2 Stakeholder Identification 44

6 Environmental Risk Assessment 46

6.1 Environmental Risk Assessment Method 46


6.2 Environmental Risk Assessment Summary 47

7 Emissions, Discharges and Wastes during Construction 48

7.1 Atmospheric Emissions 48

7.2 Noise and Vibration Emissions 48

7.3 Light Emissions 49

7.4 Discharges to Water 50

7.5 Discharges to Ground 50

7.6 Solid Non-hazardous Wastes 51

7.7 Liquid Non-hazardous Wastes 52

7.8 Hazardous Wastes 52

8 Emissions Discharges and Wastes during Operations 53

8.1 Atmospheric Emissions (Combustion) 53

8.2 Atmospheric Emissions (Dust) 59

8.3 Noise and Vibration Emissions 59

8.4 Light Emissions 60

8.5 Discharges to Water 61

8.6 Discharges to Ground 62

8.7 Solid Non-hazardous Wastes 62

8.8 Liquid Non-hazardous Wastes 63

8.9 Hazardous Wastes 63

9 Environmental Management 63

10 Works Approval Fee 64

11 Conclusion 64

12 References 65


List of Figures Figure 1-1: Regional Location of Varanus Island 7

Figure 1-2: Location of the VICPOP on Varanus Island 8

Figure 1-3: VICPOP Prescribed Premises Boundary 13

Figure 1-4: VICPOP Process Facility General Arrangement 14

Figure 1-5: VICPOP Process Facility Isometric View 15

Figure 3-1: VI Vegetation Association Map 22

Figure 3-2: Protected Migratory Bird Species Nesting Sites on VI 28

Figure 3-3: Marine Turtle Nesting Sites on VI 32

Figure 3-4: Regional Marine Habitats and Conservation Reserves 34

Figure 4-1: ESJV Gas Plant Process Block Diagram (Existing) 36

Figure 4-2: ESJV Gas Plant Process Block Diagram (Post VICPOP) 36

List of Tables Table 1-1: Characteristics of Existing Varanus Island Facilities 9

Table 1-2: VICPOP Characteristics 10

Table 1-3: Key differences between this WAA and the WAA for W5518/2013/1 11

Table 1-4: Abbreviations and Acronyms 16

Table 2-1: Primary Activities Described in Schedule 2 of L6284/1992/10 19

Table 3-1: Conservation Significant Fauna Species Potentially Occurring on VI or Surrounding Waters 23

Table 4-1: Performance Characteristics of the Proposed Humeceptor OWS 43

Table 4-2: Indicative Timing for VICPOP Activities 43

Table 5-1: Works Approval Consultation Summary 44

Table 8-1: Calculated Air Emissions from VICPOP Turbine Driven Machines under Routine Operating Conditions 55

Table 8-2: Point Source Emission Targets for during Normal Operation 55

Table 8-3: NEPM (Ambient Air Quality) Standards relevant to VICPOP 56

Table 8-4: NEPM Air Toxic Monitoring Investigation Levels and NSW EPA Assessment Criteria 57

Table 8-5: Predicted Air Emissions from VI under Routine Operating Conditions (Source: PE (2013)) 57

List of Appendices Appendix 1 – Varanus Island Emission Points to Air 68

Appendix 2 – VICPOP Process Flow Diagrams 70

Appendix 3 – Solar Turbines Data Sheets 72

Appendix 4 – Santos WA Risk Matrix 77

Appendix 5 – Santos Environmental Policy 78

Appendix 6 – VICP Air Quality Assessment (PE Report - 2013) 79

Appendix 7 – Works Approval W5518/2013/1 80


1 Introduction

1.1 Overview

Santos WA Energy Limited (Santos WA) operates the Varanus Island (VI) Hub oil and gas facilities on the North West Shelf, Western Australia (WA). The regional location of VI is presented within Figure 1-1.

In order to extend the life of the existing offshore John Brookes (JB) gas field, Santos intends to install on VI additional gas compression, electrical generation and associated utilities which together are referred to as the Varanus Island Compression and Power Optimisation Project (VICPOP; previously known as the Varanus Island Compression Project or VICP). Presently gas and associated liquids flow under natural pressure from the wellhead platform through the onshore John Brookes (JB) slug catcher then to the inlet of the amine trains on VI. Declining JB reservoir pressure means that in the future there will no longer be sufficient natural pressure to maintain the required production flow rate. The VICPOP will compensate for the future decline in reservoir pressures.

1.2 Purpose of this Document

The installation and commissioning of two gas fuelled Solar Mars 100 gas turbine driven compressors (10.5 MW each), and one gas fuelled Solar Centaur 40 powered generator (3.5 MW), will cause a change to the volume of atmospheric emissions on VI.

The purpose of this document is to provide information required to support an on-line application to the Department of Water and Environmental Regulation (DWER) for a Works Approval, pursuant to Section 53 of the Environmental Protection Act 1986 (EP Act) and the Environmental Protection Regulations 1987. This Works Approval Application (WAA) has been prepared with consideration of the following DWER

publications:

Guideline: Industry Regulation Guide to Licensing (June 2019)

Guidance Statement: Environmental Siting (November 2016)

Guidance Statement: Environmental Standards (September 2016)


Figure 1-1: Regional Location of Varanus Island


Figure 1-2: Location of the VICPOP on Varanus Island


1.3 Proponent

Santos WA is the proponent for the VICPOP. Contact details for the proponent are as follows:

Gareth Bamford

Production Offshore

Manager Gas Assets

Santos Limited, Level 7, 100 St Georges Tce, Perth WA 6000

Ph: 6218 7139

Email: [email protected]

1.4 Premises Description

VI is a prescribed premises under Part V of the EP Act and operates in accordance with a licence (L6284/192/10) for particular categories. The characteristics of the existing facilities on VI are summarised in Table 1-1 and the additional characteristics of the VICPOP, are summarised within Table 1-2.

Table 1-1: Characteristics of Existing Varanus Island Facilities

Existing Element Description

Offshore gas supply pipeline No change to the existing offshore supply pipeline from the JB platform.

Oil and gas production

Prescribed Premises Category 10 – Oil or gas production from wells: premises, whether on land or offshore, on which crude oil, natural gas or condensate is extracted from below the surface of the land or seabed, as the case requires, and is treated or separated to produce stabilized crude oil, purified natural gas or liquefied hydrocarbon gases.

No change to the existing combined quantity of quantities of oil, gas and/or condensate produced (≤ 7,050,000 tonnes per annual period). Changes to the production method are as presented in Table 1-2.

Oil or gas refining

Prescribed Premises Category 34 – Oil or gas refining: premises on which crude oil, condensate or gas is refined or processed.

No change to the existing combined quantity of quantities of oil, gas and/or condensate produced (≤ 7,050,000 tonnes per annual period). Changes to the production method are as presented in Table 1-2.

Condensate storage

Prescribed Premises Category 73

No change to the existing crude oil and condensate storage of 120,000 cubic meters and no change to existing export facilities or throughputs.

Petroleum processing operations No change to existing as 24 hours a day, 365 days a year.

Operational manning No additional manning required over and above current manning levels.

Sales gas production No additional sales gas production over and above current volumes as produced on VI and supplied into the DBNGP.

Condensate production No additional condensate production over and above current volumes produced on VI.

Produced Formation Water (PFW) volumes No change to the existing PFW production throughput.

PFW treatment and disposal No change to the existing PFW treatment and disposal

mailto:[email protected]


Existing Element Description

systems.

Sewage treatment facility. Prescribed Premises Category 85 – Sewage facility: premises –

(a) On which sewage is treated (excluding septic tanks); or

(b) From which treated sewage is discharged onto land or into waters

No change to the existing sewage treatment facility or throughputs being ≤ 54 cubic meters per day1.

Potable water No change to the existing permanent potable water production systems.

Table 1-2: VICPOP Characteristics

VICP Element Description

VICPOP gas processing plant.

Prescribed Premises Category 10 and Category 34

Two new gas fuelled Solar Mars 100 gas turbine driven compressors (10.5 MW each), module based and including scrubbers, air cooled heat exchangers, gas/gas exchanger and Joule-Thompson (JT) gas cooling valves.

VICPOP power plant.

Does not trigger a category of

Prescribed Premises

One new gas fuelled Solar Centaur 40 powered generator that will generate approximately 3.5 MW of power to be distributed throughout the VICP plant at 11 kV.

1.5 Project History

Works Approval History

A WAA for VICPOP was previously submitted to the then Department of Environment Regulation (DER; now the Department of Water and Environmental Regulation; DWER) and subsequently Works Approval W5518/2013/1 was approved on 19 December 2013 (Appendix 7). Works for VICPOP commenced in September 2013, however in circa June 2014 the project was suspended and deferred.

On 22 December 2016 Works Approval W5518/2013/1 expired and therefore is no longer in force. On 1 July 2019 planning for completion of VICPOP commenced with the additional scope to optimise power supply on VI. In terms of gas compression, Santos WA is aiming for a ready for start-up (RFSU) date of Q1 2021.

This WAA remains effectively unchanged from the original application for Works Approval W5518/2013/1, with minor updates to account for the company name change, summary of completed works and alignment to current DWER guidance material. Key differences between this WAA and the WAA for W5518/2013/1 are summarised in Table 1-3.

As Built Status

Of the VICPOP works described in WAA for W5518/2013/1, the following were completed by June 2014:

VICP preparatory works including removal of redundant facilities as a maintenance activity, site preparation, levelling and creation of laydown areas.

Site preparation using heavy machinery, such as excavators, bull dozers and tipper trucks.

1 Note: Works Approval W6266/2019/1 has been issued for the construction of a 72 m3 per day Sewage Treatment Plant (STP).


Realignment of the existing bund wall and bun liner modification works.

Infill, compaction, retaining wall installations and stormwater drainage works.

Installation of compressor module foundations, power generator foundations, electrical and battery room foundations and transport of the modules and power generator to a preservation facility in Henderson, WA.

Table 1-3: Key differences between this WAA and the WAA for W5518/2013/1

WAA for W5518/2013/1 This WAA

Project previously referred to as the Varanus Island Compression Project or VICP

Project herein referred to as the Varanus Island Compression and Power Optimisation Project (VICPOP)

References to Apache

At the time W5518/2013/1 was issued, Apache Northwest Pty Ltd, a subsidiary of Apache Energy Limited (an Australian operating subsidiary of Apache Corporation), operated the oil and gas production and infrastructure facilities located on Varanus Island (VI) on behalf of its joint venture participants.

Santos WA Energy Limited (Santos WA) now operates the oil and gas production and infrastructure facilities on VI on behalf of its joint venture participants and will be responsible for all commitments and obligations in this WAA.

Table 1-1: Characteristics of Existing Varanus Island Facilities

Updated to reflect current Licence L6284/1992/10 (i.e. addition of Category 34)

Section 2.1 – Reference to Construction Environmental Management Plan (CEMP) approved by the Department of Mines and Petroleum (now the Department of Mines, Industry Regulation and Safety; DMIRS).

The CEMP previously referred to has expired. Santos WA has prepared a CEMP bridging to the current approved Varanus Island Hub Operations Environment Plan (VI Hub Operations EP) (Doc. Ref: WA-60-RI-186) that will be submitted to DMIRS for approval prior to the commencement of construction (refer to Section 2.1).

Section 2.2 – Licences and Works Approvals

Section Error! Reference source not found. – Operating licence and Categories of Prescribed Premises updated in-line with the current Licence L6284/1992/10.

Table 3-1: Conservation Significant Fauna Species Potentially Occurring on VI or Surrounding Waters

Updated to reflect revised EPBC matter search and protected fauna under the WA Biodiversity Conservation Act 2016 (BC Act) and WA Wildlife Conservation (Specially Protected Fauna) Notice 2018

Section 4.6 – VICP Construction Summary

Preparatory works are not relevant to this WAA and therefore their description has been removed. Section 1.5 outlines the Works Approval history and details works completed under W5518/2013/1.

Section 4.5.6 – Stormwater and Site Drainage Details on the performance characteristics of the proposed humeceptor oily water system have been added to Section 4.5.6.

Section 7 – Emissions, discharges and wastes arising from construction within the VICPOP works

Emissions, discharges and wastes arising from construction within the VICPOP works area will be


WAA for W5518/2013/1 This WAA

area will be managed in accordance with the Construction Environmental Management Plan (CEMP) (Doc. Ref: JB-10-RI-002)

managed in accordance with a CEMP bridging to the current approved VI Hub Operations EP (refer to Section 2.2) and the requirements as identified within the VICPOP Commitments Register (Doc. Ref: JB-10-HI-001).

Section 6 – Environmental Risk Assessment

Section 6 has been amended to explain that the Environmental Risk Assessment for the VICPOP works undertaken in 2012 used an Apache risk matrix. This has been superseded by the Santos WA risk matrix (refer to Appendix 4) and therefore all sections relating to risk assessments were reviewed and re-mapped in the preparation of this WAA. Risk assessment outcomes in Section 7 and Section 8 now reflect the current Santos WA risk matrix.

Figure 1.3: VICPOP Prescribed Premises Boundary

Minor variations to the previous VICPOP prescribed premises boundary, which is embedded within the VI prescribed premises boundary, along the VICPOP plate area access road and East Spar Gas Plant boundaries.

1.6 Scope of this Works Approval Application

The scope of this WAA is limited to the installation and commissioning of two gas fuelled Solar Mars 100 gas turbine driven compressors and one gas fuelled Solar Centaur 40 powered generator as defined in Table 1-2 and located within the proposed Prescribed Premises (Figure 1-3). A general arrangement of the facilities is presented in Figure 1-4Error! Reference source not found. and an isometric view presented in Figure 1-5. Note the other facilities and supporting infrastructure (e.g. roads) illustrated in the general arrangement are shown for completeness only and are not the subject of this WAA.


Figure 1-3: VICPOP Prescribed Premises Boundary


Figure 1-4: VICPOP Process Facility General Arrangement


Figure 1-5: VICPOP Process Facility Isometric View


1.7 Abbreviations and Acronyms

Table 1-4: Abbreviations and Acronyms

Abbreviation Definition

AHD Australian Height Datum

ALARP As Low as Reasonably Practicable

APPEA Australian Petroleum Production and Exploration Association

AS/NZS Australian / New Zealand (Standard)

BTEX Benzene, Toluene, Ethylbenzene, Xylene

Cth Commonwealth (of Australia)

CALM Department of Conservation and Land Management (WA)

CEMP Construction Environmental Management Plan

CO Carbon Monoxide

CO2 Carbon Dioxide

DBNGP Dampier to Bunbury Natural Gas Pipeline

DEC Department of Environment and Conservation (WA)

DER Department of Environment Regulation (WA)

DMIRS Department of Mines, Industry Regulation and Safety

DMP Department of Mines and Petroleum (WA)

DWER Department of Water and Environmental Regulation

EAG Environmental Assessment Guideline

EP Act Environmental Protection Act 1986 (WA)

EPA Environmental Protection Authority

EPBC Act Environment Protection and Biodiversity Conservation Act 1999 (Cth)

ESJV East Spar Joint Venture

g/m3 Grams per cubic metre

g/s Grams per second

HDPE High-density Polyethylene

HJV Harriet Joint Venture

HP High Pressure

JB John Brookes

JT Joule-Thompson

km Kilometre

kV Kilovolt

oK degrees Kelvin

MS Ministerial statement

MW Megawatt


Abbreviation Definition

m Metre

m3 Cubic metre

m/s Metres per second

MMSCFD Million Standard Cubic Feet per Day

NDE Non-destructive Examination

NEPM National Environment Protection Measure

Nm3 Normal Cubic Metres (at 0 oC)

mg/Nm3 Milligrams per Normal Cubic Metre

NOX Oxides of Nitrogen

NO2 Nitrogen Dioxide

NPI National Pollution Inventory

ppm Parts per million

PB Parsons Brinkerhoff

PE Pacific Environment Limited

PFW Produced Formation Water

PL Pipeline Licence

PM10 Particulate Matter (10 microns or less)

Rsmog A summary measure of volatile organic compounds

RO Reverse Osmosis

SEWPaC Department of Sustainability, Environment, Water, Population and Communities

SO2 Sulphur Dioxide

SoLoNOX Solar Turbines proprietary low combustion emissions technology

SSE South-southeast

tpa Tonnes per annum

TJ/day Terra Joules per Day

VI Varanus Island

VICP Varanus Island Compression Project

VICPOP Varanus Island Compression and Power Optimisation Project

VOC Volatile Organic Compound

WA Western Australia

WAA Works Approval Application

μg/Nm3 Micrograms per normal cubic metre

oC Degrees Celcius


2 Existing Varanus Island Licences and Environmental

Approvals

2.1 Leases

VI is part of the Lowendal group of islands which are vested as a nature conservation reserve (33902) and are managed by the Department of Biodiversity, Conservation and Attractions (DBCA). In order to operate petroleum activities on VI, a lease was required from the then Department of Conservation and Land Management (CALM), under the Conservation and Land Management Act 1984 (CALM Act).

In 1986, the CALM Executive Body granted lease 1902/100 over portions of Reserve 33902 to the Harriet Joint Venture (HJV) for the operation of petroleum receiving, processing and loading/export facilities. A portion of lease 1902/100 was subsequently annexed as a new lease 2604/100 granted to the East Spar Joint Venture (ESJV).

The leases were renewed in April 2013 and have a term concurrent with the term of the two petroleum Pipeline Licences (PL12 and PL29 granted by the DMIRS) within the VI lease area that have been granted to Santos WA, pursuant to the Petroleum Pipelines Act 1969.

In respect of the Pipeline Licences, the DMIRS has, for the purpose of the proposed VICPOP works, provided to Santos WA authorisations to carry out VICPOP works by way of the following instruments:

Variation No. STP-PLV-0024 in respect of VICP works within the PL12 Licence Area.

Variation No. STP-PLV-0025 in respect of VICP works within the PL29 Licence Area.

2.2 Environmental Approvals

Varanus Island Hub Facilities that have been previously assessed under Part IV of the EP Act include the following:

MS 134: Pipeline, Harriet Gas Field to Dampier-Wagerup Pipeline, Dampier.

MS 395: East Spar Off-shore Gas Field Development, Varanus Island.

MS 457: Wonnich Gas Development, South-west of the Montebello Islands.

MS 573: Simpson Oil Field Development, Offshore Abutilon Island, Lowendal Islands.

The VICPOP does not require amendments to the existing ministerial statements.

Within the Santos WA lease, Santos WA holds clearing permit CPS7551/1 (valid to 31 July 2027) and CPS CPS5563/2 (valid to August 2028). No clearing of native vegetation is required within the area subject to this WAA.

In respect of the environmental approvals required for the VICPOP, Santos WA has:

Under the EP Act, submitted a Section 38 referral to the Environmental Protection Authority (EPA). On the 13 March 2013, Santos WA received determination advice as ‘Not Assessed – Public Advice Given’.

Under the Environment Protection and Biodiversity Conservation Act 1999 (Cth) (EPBC Act), submitted a referral (Referral 1) to the Department of Sustainability, Environment, Water, Population and Communities (Cth) (SEWPaC, now the Department of the Environment and Energy; DOTEE) for the VICPOP earthworks phase. On the 15 July 2013, Santos WA received a referral decision as ‘Not controlled if undertaken in a particular manner’ (EPBC 2013/6900).

Under the EPBC Act, submitted a referral (Referral 2) to SEWPaC to construct and operate a kitchen/mess cyclone refuge building, compression plant and accommodation camp. On the 22 October 2013, Santos WA received a referral decision as 'Not controlled if undertaken in a particular manner' (EPBC 2013/6952).


Prepared and submitted to the Department of Mines, Industry Regulation and Safety (DMIRS) a Written Notification to allow for the commencement of preparatory works (approval pending at the time of WAA submission).

Prepared a Construction Environmental Management Plan bridging to the current approved VI Hub Operations EP that will be submitted to DMIRS for approval prior to the commencement of construction.

The VI based petroleum producing facilities are classed as a ‘Prescribed Premises’ under the EP Act

based on particular categories. In respect of the existing VI based petroleum operations, Santos WA has been granted an operating licence (L6284/1992/10) by the DWER for the primary activities described in Schedule 2 of L6284/1992/10 (see Table 2-1 below).

Table 2-1: Primary Activities Described in Schedule 2 of L6284/1992/10

Primary Activity Premises production or design capacity

Category 10 – Oil or gas production from wells: premises, whether on land or offshore, on which crude oil, natural gas or condensate is extracted from below the surface of the land or seabed, as the case requires, and is treated or separated to produce stabilized crude oil, purified natural gas or liquefied hydrocarbon gases.

≤ 7,050,000 tonnes per

annual period

Category 34 – Oil or gas refining: premises on which crude oil, condensate or gas is refined or processed.

Category 85 – Sewage facility: premises –

(a) On which sewage is treated (excluding septic tanks); or

(b) From which treated sewage is discharged onto land or into waters

≤ 54 cubic meters per day2.

The intended VICPOP works do not alter or modify the production throughputs currently approved under the operating licence (L6284/1992/10).

2.3 Assessable Works

As stated in Section 1.5.1, the Works Approval W5518/2013/1 previously granted for VICPOP has expired. Therefore, in accordance with Section 53 of the EP Act, Santos WA is required to submit a WAA for the existing Categories of prescribed premises to allow for the construction and commissioning of:

Two new gas fuelled Solar Mars 100 gas turbine driven compressors (Tag No’s K0302 and

K0402).

One new gas fuelled Solar Centaur 40 powered generator (Tag No G9001).

Reference should be made to Appendix 1 that provides a drawing of current VI combustion emission sources and also the new emission sources the subject of this WAA.

2 Note: Works Approval W6266/2019/1 has been issued for the construction of a 72 m3 per day Sewage treatment Plant (STP).


3 Existing Environment

3.1 Climate

The climate of the region in which VI is located is arid, subtropical with hot summer temperatures and low and unpredictable rainfall, high evaporation, occasional cyclones and associated summer rainfall. The annual average rainfall of the Lowendal Islands is approximately 300 mm, mostly as a result of tropical cyclones.

The summer and winter seasons fall into the periods September-March and May-July, respectively. Winters are characterised by clear skies, fine weather, predominantly strong east to south-east winds and infrequent rain. Summer winds are more variable, with strong south-westerly’s dominating. Three

to four tropical cyclones per year are typical, primarily between December and March (WNI, 1995). The months of April and August to September are considered transitional between summer and winter.

Average surface air temperatures range from 34.2°C (maximum) and 24.8°C (minimum) in summer to 25.2°C (maximum) and 17.1°C (minimum) in winter. Climatic data is monitored and recorded by an automated weather station on VI.

The winds in the area show a marked seasonal variation. During winter (May to July), moderate to strong south-easterlies and north-easterlies to easterlies prevail, while during summer (September to March) moderate southerly, south-westerly and westerly winds dominate. April and August to September are transitional months where the wind can blow from the south-west to south-east.

Extreme wind conditions may be generated in the area by tropical cyclones, strong easterly pressure gradients, squalls, tornadoes and waterspouts. Tropical cyclones generate the most significant storm conditions on the North West Shelf (SSE, 1993). These clockwise-spiralling storms have generated wind speeds of 50 to 120 knots within the region (SSE, 1991). Since recordings began in 1960/61, tropical cyclones have approached the area from the north-west through to east, with the most frequent directions being from the north (34%) and east (36%). However, due to the circular wind patterns involved, winds can approach from any direction during the passage of the storm.

The frequency of occurrence of tropical cyclones is an important physical environmental factor influencing the marine fauna, particularly corals, in shallow water within the Lowendal Islands.

3.2 Geomorphology

The Lowendal group of islands are low lying limestone rock, some covered in vegetation, others being rock with few plants to be found. The formation is comprised of lime-cemented dune sands that were deposited during the Pleistocene.

Shoreline profiles for the islands are typically steep, and contain relatively narrow low intertidal zones, which dip onto the extensive shallow sub-tidal platform that characterise the area. Both the lower intertidal and shallow sub-tidal zones comprise semi-planar limestone pavement (DEC, 2007).

The topography of VI is flat to undulating low dunes. The elevation ranges from sea level to a maximum of 18 m Australian Height Datum (AHD). Outcropping occurs over much of the Santos WA lease area on VI, particularly in the eastern and south-eastern areas (Parsons Brinckerhoff, 2005).

3.3 Groundwater

In 2012, Parsons Brinckerhoff (PB) conducted a soil and groundwater investigation in the main bund area, where the VICPOP works are proposed (Parsons Brinckerhoff, 2012). The groundwater table over most of the VI lease is present at an elevation of 1.8 m AHD at low tide and 2.6 m AHD at high tide (PB, 2012). Groundwater contours prepared by Parsons Brinckerhoff (PB, 2012) show that the groundwater levels around the VICPOP works area range between 1.8 to 1.9 m AHD. The design sub-


grade level for the VICPOP is approximately 9 m AHD (i.e. approximately 7 m above the identified water table).

3.4 Surface Water

The rocky nature and limited extent of VI, together with generally arid conditions preclude the retention of surface water.

The VICPOP works area within the existing facilities has a storm water catchment and drainage area of approximately 0.9 ha.

3.5 Vegetation and Flora

Terrestrial vegetation

The vegetation of VI is located in the Fortescue Botanical District, which is part of the Eremaean Botanical Province (Beard, 1975). The vegetation of VI is broadly described as ‘desertic’ dominated by

hummock grasslands (Triodia spp).

The primary substrate and vegetation division on VI occurs between limestone and sand. Six broad vegetation assemblages, distinguished on the basis of the relative abundance of species and/or vegetation structure, have been described by Semeniuk (1992). The assemblages (A to F) are:

A. Low (to 20 cm) open herbland of Frankenia pauciflora on exposed limestone, which is exposed to wind and sea spray and has poorly developed soil.

B. Low (to 50 cm) open shrubland of Scaevola spinscens, Rhagodia preissii and Sarcostemma viminale subsp australe (formerly S. australe) on limestone plains and ridges inland from the exposed coastal limestone.

C. Low (to 50 cm) open shrubland of Sarcostemma viminale subsp. australe, Capparis spinosa and Pittosporum phylliraeoides on more sheltered and inland parts of undulating limestone terrain.

D. Open grassland of Spinifex longifolius on white sands of coastal dunes.

E. Closed mixed grassland/herbland of Setaria dielsii and Amaranthus pallidiflorus on the deeper orange sands of inland plains.

F. Low (to 50 cm) open shrubland of Sarcostemma viminale subsp. australe with mixed grassland on orange sand particularly where it is shallow over limestone.

More detailed vegetation association mapping has been completed by Astron Environmental Services (Astron) since 1992 as presented in Figure 3-1.

From the Figure, it can be seen that VICPOP works are to be undertaken within an area that is devoid of vegetation and therefore the works proposed within the VICPOP area will not require the clearing of any native vegetation.


Figure 3-1: VI Vegetation Association Map


Intertidal Vegetation

Three species of mangrove are found throughout the Lowendal Islands area including Avicennia marina, Rhizophora stylosa and Aegiceras corniculatum. All three species are present on Bridled Island, while only A. marina is present on Varanus and Abutilon islands. The occurrence of mangroves within the Lowendals is very restricted, being largely determined by local geomorphology, substrates and soil water and groundwater salinity (LeProvost Semenuik and Chalmer, 1988).

Terrestrial Flora

A total of 122 species have been recorded on VI and Bridled Islands (Astron, 2009b). No Wildlife Conservation (Rare Flora) Notice 2018 listed threatened (critically endangered, endangered or vulnerable) flora are known to occur on the islands. Eight flora species have very restricted distributions on VI and are considered locally significant (Astron, 2009).

Introduced Plants

Fourteen weed species and eight introduced mainland species have been recorded on VI (Astron, 2011) since 2000.

3.6 EPBC Act-listed Species

The Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) lists threatened and migratory fauna species that are protected under Commonwealth legislation and various international conventions and treaties. A search of the EPBC Act Protected Matters Database was conducted using a 10-km radius search area from a central location coordinate on Varanus Island.

The search identified 19 listed threatened fauna species potentially occurring on Varanus Island or within the surrounding waters, the majority of which are also listed as migratory species. An additional 40 species were listed as migratory species. These species, together with their respective conservation status under the WA Biodiversity Conservation Act 2016 (BC Act) and WA Wildlife Conservation (Specially Protected Fauna) Notice 2018 are summarised in Table 3-1.

Table 3-1: Conservation Significant Fauna Species Potentially Occurring on VI or Surrounding

Waters

Common Name Scientific Name EPBC Act Status BC Act Status

Sharks & Rays

Dwarf Sawfish Pristis clavata Threatened – Vulnerable, Migratory Marine

None

Giant Manta Ray Manta birostris Migratory Marine None

Green Sawfish Pristis zijsron Threatened – Vulnerable, Migratory Marine

Schedule 2

Grey Nurse Shark Carcharias taurus Threatened – Vulnerable Schedule 3

Narrow Sawfish Anoxypristis cuspidata Migratory Marine None

Reef Manta Ray Manta alfredi Migratory Marine None

Whale Shark Rhincodon typus Threatened – Vulnerable, Migratory Marine

Schedule 6

White Shark Carcharodon carcharias Threatened – Vulnerable, Migratory Marine

Schedule 3

Marine mammals



Blue Whale Balaenoptera musculus Threatened – Endangered, Migratory Marine

Schedule 2

Bryde’s Whale Balaenoptera edeni Migratory Marine None

Dugong Dugong dugon Migratory Marine Schedule 7

Humpback Whale Megaptera novaeangliae Threatened – Vulnerable, Migratory Marine

Schedule 6

Indo-Pacific Humpback Dolphin

Tursiops aduncus Migratory Marine None

Killer Whale Orcinus orca Migratory Marine None

Spotted Bottlenose Dolphin (Arafura/Timor Sea populations)

Tursiops aduncus Migratory Marine None

Marine reptiles

Green Turtle Chelonia mydas Threatened – Vulnerable, Migratory Marine

Schedule 3

Flatback Turtle Natator depressus Threatened – Vulnerable, Migratory Marine

Schedule 3

Hawksbill Turtle Eretmochelys imbricata Threatened – Vulnerable, Migratory Marine

Schedule 3

Leatherback Turtle Dermochelys coriacea Threatened – Endangered, Migratory Marine

Schedule 3

Loggerhead Turtle Caretta caretta Threatened – Endangered, Migratory Marine

Schedule 2

Short-nosed Seasnake Aipysurus apraefrontalis Threatened – Critically Endangered

Schedule 1

Birds

Australian Painted-snipe Rostratula australis Threatened – Endangered Schedule 2

Australian Fairy Tern Sternula nereis nereis Threatened – Vulnerable Schedule 3

Barn Swallow Hirundo rustica Migratory Terrestrial Schedule 5

Bridled Tern Sterna anaethetus Migratory Marine Bird Schedule 5

Caspian Tern Sterna caspia Migratory Marine Bird Schedule 5

Common Greenshank Tringa nebularia Migratory Wetland Schedule 5

Common Noddy Anous stolidus Migratory Marine Bird Schedule 5

Common Sandpiper Actitis hypoleucos Migratory Wetland Schedule 5

Crested Tern Thalasseus bergii Migratory Wetland Schedule 5

Curlew Sandpiper Calidris ferruginea Threatened – Critically Endangered, Migratory Wetland

Schedule 1



Eastern Curlew Numenius madagascariensis

Threatened – Critically Endangered, Migratory Wetland

Schedule 5

Fork-tailed Swift Apus pacificus Migratory Marine Bird Schedule 5

Grey Wagtail Motacilla cinerea Migratory Terrestrial Schedule 5

Lesser Frigatebird Fregata ariel Migratory Marine Bird Schedule 5

Osprey Pandion haliaetus Migratory Wetland Schedule 5

Pectoral Sandpiper Calidris melanotos Migratory Wetland Schedule 5

Red Knot Calidris canutus Threatened – Endangered, Migratory Wetland

Schedule 2

Roseate Tern Sterna dougallii Migratory Marine Bird Schedule 5

Southern Giant-Petrel Macronectes giganteus Threatened – Endangered, Migratory Marine Bird

Schedule 5

Sharp-tailed Sandpiper Calidris acuminata Migratory Wetland Schedule 5

Streaked Shearwater Calonectris leucomelas Migratory Marine Bird Schedule 5

Wedge-tailed Shearwater Puffinus pacificus Migratory Marine Bird Schedule 5

Yellow Wagtail Motacilla flava Migratory Terrestrial Schedule 5

Schedule 1 Fauna that is rare or is likely to become extinct as critically endangered fauna

Schedule 2 Fauna that is rare or is likely to become extinct as vulnerable fauna

Schedule 3 Fauna that is rare or is likely to become extinct as vulnerable fauna

Schedule 5 Migratory birds protected under an international agreement

Schedule 6 Fauna that is of special conservation need as conservation dependant fauna

Schedule 7 Other specially protected fauna

The VICPOP works as described within this WAA are entirely land-based with little to no potential to impact on the surrounding marine waters, other than those directly adjacent to the island. As such, impacts on marine fauna which are largely offshore species are considered to be negligible.

3.7 Terrestrial, Avian and Subterranean Fauna

Terrestrial Fauna

The predominant types of vertebrate terrestrial fauna on VI are reptiles, as presented within the Phoenix (2012a) literature search that identified thirteen reptile species occurring on VI. No terrestrial vertebrate fauna species of conservation significance have been recorded within the VICPOP works area. There are no native mammals, endemic or introduced, present on VI (Phoenix, 2012a).

Avifauna

Of the following bird species that are known to breed on VI, the roseate tern and Australian fairy tern are listed threatened species under the EPBC Act and specially protected fauna under the BC Act. Many of the following bird species are migratory (i.e. may over-fly the island from time-to-time in transit or while foraging):


Crested Tern (Thalasseus bergii)

Lesser Crested Tern (Sterna bengalensis)

Bridled Terns (Sterna anaethetus)

Caspian Terns (Sterna caspia)

Roseate Terns (Sterna dougallii)

Australian Fairy Terns (Sterna nereis)

Pied Cormorants (Phalacrocorax varius)

Silver Gulls (Larus novaehollandiae)

Brown Boobies (Sula leucogaster)

Ospreys (Pandion haliaetus)

White-bellied Sea Eagles (Haliaeetus leucogaster)

Wedge-tailed Shearwaters (Puffinus pacificus).

Santos WA commissioned a survey of the avifauna in November 2012 in relation to bird species potentially affected by the VICPOP works. Of the bird species listed above, only the wedge-tailed shearwater, lesser crested tern and bridled tern are known to nest in the vicinity of the VICPOP works area (Halfmoon Biosciences, 2012). In a more recent survey undertaken by Pendoley (2019), the wedge-tailed shearwater was the only species observed nesting in the vicinity of the VICPOP works area. Although the pied Cormorant and Crested Tern nest on VI, they aren’t considered to be in close proximity to the VICPOP works area (refer to Figure 3-2).

3.7.2.1 Wedge-tailed Shearwater

The wedge-tailed shearwater (Ardenna pacifica formerly known as Puffinus pacificus) is listed as migratory and marine under the EPBC Act. The species has a wide distribution in the tropical Pacific and Indian Oceans and has a large global population, estimated at over five million birds (Brooke, 2004). In Australia, the wedge-tailed shearwater is a common breeding and nonbreeding visitor to the coastal and pelagic waters of east and west Australia (Marchant & Higgins, 1990). It is common off the WA coast from August to April and breeds off the mid-west and south-west Western Australian coast (Marchant & Higgins, 1990).

The wedge-tailed shearwater is a burrowing species that on VI lays a single egg during early November which is then incubated until the chick hatches (after 53 days) in early January. Chicks grow slowly (it takes approximately 97 days to fledge), are fed only at night by their parents, and remain in the burrow until they are ready to fledge in mid-April (Nicholson, 2002).

Santos WA has monitored wedge-tailed shearwaters on VI and adjacent islands since 1987. Monitoring undertaken from 2005 to present indicates that shearwater burrow numbers have not changed significantly at VI over the monitoring period (Halfmoon Biosciences, 2012). The wedge-tailed shearwater colonies scattered throughout sandy regions of VI (refer to Figure 3-2) appear to have remained relatively stable since 2005/2006, and collectively contained a total of 247 burrows (Halfmoon Biosciences, 2012).

Results of the 2018/19 monitoring season demonstrated that the estimated size of the wedge-tailed shearwater colony on VI were within or above previously reported ranges. Analysis of the long-term dataset indicated that environmental conditions influenced every breeding parameter measured. Trends in burrow density and breeding participation at VI suggest that operations here have not resulted in detrimental changes to WTS population size or breeding participation on this island (Pendoley, 2019).

3.7.2.2 Bridled Tern

The bridled tern (Onychoprion anaethetus) is listed as migratory and marine under the EPBC Act. The species has widespread distribution, breeding on offshore islands in western, northern and north-eastern Australia. In Western Australia, breeding is widespread from islands off Cape Leeuwin


(extending round the southern coast to Seal Rocks), north to Shark Bay and in Pilbara and Kimberley regions.

In the Lowendal Islands, there are >10,000 pairs, with 3,000–4,000 pairs on Bridled Island. Nests are usually found in rocky areas, concealed in crevices or caves up to 1.5 m deep, under rocks, among talus or coral rubble, on ledges of cliffs, on the ground beneath low shrubs, or among grasses. The bridled tern roosts ashore when breeding (SEWPaC, 2012f).

Bridled terns return to VI in late November and nest between late December and April. In 2012, the colony on VI consisted of 20 individual nests, compared to 590 nests on Parakeelya (approximately 5 km north-west of VI) (Halfmoon Biosciences, 2012). There were several bridled tern nests along coastal cliffs adjacent to the east wharf, as well as a single nest abutting the west wharf.

Santos WA has monitored bridled terns on VI and adjacent islands since 1987 and bridled terns are known to only nest in very small numbers on VI. Bridled terns were not recorded nesting on VI in 2019. Surveyed control islands with larger populations of Bridled Terns have shown an increase in numbers recently, with the exception of Abutilon Island, which showed a significant decrease in Bridled Tern breeding numbers (Astron Environmental Services, 2019).

Figure 3-2 indicates the nesting sites on VI of the three migratory bird species that are protected under the EPBC Act.


Figure 3-2: Protected Migratory Bird Species Nesting Sites on VI


Subterranean Fauna

Subterranean fauna are organisms (almost exclusively invertebrates) that live beneath the surface of the ground. Subterranean organisms can exist within a variety of subterranean void networks, including solution cavities within calcrete and karst, fractured rock and course sediments such as cobble or gravel strata (Howarth 1983; Humphreys, 2008; Subterranean Ecology, 2010, cited in Phoenix, 2012a). Organisms specialised for living in air-filled subterranean networks are referred to as troglofauna, while those inhabiting water-filled subterranean networks are referred to as stygofauna (Howarth, 1983; Humphreys 2000a cited in Phoenix, 2012a).

No subterranean fauna surveys have been conducted to date on VI. In the absence of systematic surveys, the likely presence and distribution of troglofauna and stygofauna on VI has been assessed based on the geology of VI and corresponding geologies on Barrow Island, which support subterranean fauna (Phoenix, 2012a). VI is comprised of a single geological type described as Pleistocene coastal limestone covered by lime-cemented shelly sand, dune sand and beach conglomerate. This geology is well represented on the eastern side of Barrow Island where extensive subterranean fauna, both troglofauna and stygofauna, has been recorded. It is therefore likely that both troglofauna and stygofauna are present on VI (Phoenix, 2012a). The potential extent of troglofauna and stygofauna habitat is believed to correspond with the extent of the island because of the uniformity in geology across the island (Phoenix, 2012a). Hence, if troglofauna and stygofauna are present within the Santos WA lease area, they are also likely to be present elsewhere on VI.

Marine Turtles

The Western Australian green and hawksbill turtle populations are some of the largest populations remaining in the world (Limpus 2002; 2009). The North-west Marine Region supports globally significant breeding populations of green, hawksbill, loggerhead and flatback turtles (SEWPaC, 2012a).

Four of the five species of marine turtles listed under the EPBC Act, nest on sandy shore sites of the Dampier Archipelago, Montebello Islands, Lowendal Islands, Barrow Island, the coastal islands between Dampier and Exmouth Cape, Airlie Island, Thevenard Island and the North West Cape. These are the green turtle (Chelonia mydas), flatback turtle (Natator depressus), hawksbill turtle (Eretmochelys imbricata) and loggerhead turtle (Caretta caretta). The leatherback turtle (Dermochelys coriacea) has the greatest distribution worldwide, but are uncommon throughout their range, rarely breed in Australia and are not known to nest on the beaches of VI. Additionally, the loggerhead turtle has a more temperate distribution with the Muiron Islands supporting the largest regional population and the Dampier Archipelago being the northern limit of their distribution (Pendoley, 2012).

The most common species of turtle found nesting on VI is the hawksbill turtle. Flatback turtles are also frequently seen while green turtles are the least common. In an assessment of the preferred nesting beaches on VI conducted in 2019 (Pendoley, 2019), hawksbill turtle nesting activity was notably higher on Pipeline Beach compared to other monitored beaches, and individuals showed high site fidelity to this beach. Flatback turtle nesting activity was high on Pipeline Beach and Harriet Beach but showed higher site fidelity to Harriet Beach and Tanny’s Beach. Figure 3-3 indicates the marine turtle nesting sites on VI.

3.7.4.1 Hawksbill Turtle

The hawksbill turtle is listed as vulnerable under the EPBC Act and is a matter of national environmental significance. The WA breeding stock is genetically distinct from the northern Great Barrier Reef, Torres Strait and Arnhem Land stocks. The total population of hawksbill turtles in the North-west Marine Region is unknown; however it is estimated to be in the thousands, making it one of the largest in the Indo-Pacific region and one of the largest in the world (SEWPaC, 2012c).

Nesting occurs throughout the year in Western Australia, peaking between September and November (Pendoley, 2012). The most significant hawksbill turtle rookery in Western Australia is located on Rosemary Island in the Dampier Archipelago, it is believed to support up to 2,600 nesting females annually. This rookery is not only significant on a regional scale but is considered to be globally


significant and is one of the largest in the Indian Ocean, with numbers one-to-two orders of magnitude higher than numbers documented at any other Western Australian rookery. By comparison, relatively low levels of nesting occurs within the Barrow, Lowendal and Montebello islands, with approximately 2,400 nesting females recorded over these three areas inclusively (Pendoley, 2005). Of the populations of nesting females recorded within the Barrow, Lowendal and Montebello islands using track counts as a proxy for nesting female counts, 52% were recorded within the Montebello Islands, 37% within the Lowendal Islands and 10% on Barrow Island (Pendoley, 2005).

Pipeline Beach on VI is the second largest hawksbill turtle rookery in the Lowendal Islands after Beacon Island (Pendoley, 2012). Historical data gathered between 2005 and 2011 showed that numbers of hawksbill turtles tagged at VI ranged from 22 to 42 per annum (Pendoley, 2011).

During the 2018/19 turtle monitoring, 46 individual hawksbill turtles were encountered, of which 13 were new individuals. No significant trends from 1986 were identified at Anderson, Pipeline, or Harriet beaches, although a significant, increasing trend was seen at Tanny’s Beach. A notable decreasing trend in hawksbill counts at Pipeline Beach has been noted from around 2008 which could be indicative of a decline in hawksbill numbers, either at VI or more regionally (Pendoley, 2019).

3.7.4.2 Flatback Turtle

The flatback turtle is listed as vulnerable under the EPBC Act and is a matter of national environmental significance. The total population of flatback turtles in the North-west Marine Region is unknown and data on population trends are unavailable, although it is known that there are two genetically distinct populations, the North-west Shelf stock and the Western Northern Territory stock (SEWPaC, 2012c).

The flatback turtle has been recorded breeding in Western Australia from Exmouth north to Cape Domett on the Kimberley coast (Woodside, 2006). Breeding in the Pilbara peaks between December and February and significant rookeries are known to occur on Barrow Island, the Montebello Islands, Thevenard Island, the Lowendal Islands and islands of the Dampier Archipelago. Flatback turtles are known to feed throughout Australian continental shelf waters (Woodside, 2006); sub-tidal and inshore, in shallow, soft bottom habitats in depths of 10 m to over 40 m feeding on benthic organisms (SEWPaC, 2012c). The most significant flatback turtle rookery within the region is Barrow Island, followed by the Montebello Islands. The Lowendal Islands accounted for only 16% of nesting flatback turtles (Pendoley, 2005). As such, the Lowendal Islands which includes VI, forms a relatively small proportion of the region’s flatback turtle nesting habitat.

Tanny’s Beach on the west coast of VI is the main flatback turtle nesting beach in the Lowendal Islands. During the 2018/19 turtle monitoring, 63 individual flatback turtles were encountered, of which 22 were new individuals. When considering tagging data from 1986, a significant increase in flatback turtle counts was seen at Harriet Beach in both the December and January time period, and at Pipeline and Tanny’s beaches in the January time period only (Pendoley, 2019).

3.7.4.3 Green Turtle

The green turtle is listed as vulnerable under the EPBC Act and is a matter of national environmental significance. In the North-west Marine Region there are three genetically distinct populations. These are the North-west Shelf stock, the Scott Reef stock and the Ashmore stock (Dethmers et al., 2006). The North-west Shelf stock is estimated at approximately 20,000 individuals (SEWPaC, 2012c). Population estimates are not available for the Ashmore Reef or Scott Reef stocks, although annual breeding numbers are thought to be in the hundreds (Whiting et al., 2000).

The green turtle is the most widespread and abundant turtle species in Western Australian waters (Limpus, 2002), nesting from the Ningaloo coast to the Kimberley islands (Prince, 1994). Major nesting rookeries are found on the Lacepede, Montebello, Barrow, Lowendal, Serrurier, Browse and Rosemary islands, as well as on the north-east coast of Legendre Island and the western and eastern shores of Delambre Island (Woodside, 2006). A number of smaller nesting sites can also be found on the mainland between the Ningaloo and Kimberley coasts. In WA, nesting occurs between November


and March (SEWPaC, 2012e). Green turtles are herbivores, feeding on seagrass and/or algae in shallow benthic habitats, including coral and rocky reefs, and inshore seagrass beds.

The most significant green turtle rookeries within the region are found primarily within the Montebello Islands, followed by Barrow Island. The Lowendal Islands accounted for less than 1% of nesting green turtles (Pendoley, 2005). Green turtles are the least common turtle to nest on VI with the 2019 turtle monitoring program only assessing three individuals (Pendoley, 2019). Similar results were also recorded during the previous monitoring programs.


Figure 3-3: Marine Turtle Nesting Sites on VI


3.8 Noise

Noise levels within the proposed VICPOP works area are entirely influenced by noise generated by the existing gas processing equipment. There is no evidence that elevated noise levels emanating from within the Santos WA lease area are detrimental to the adjacent seabird rookery areas (Halfmoon, 2012) nor to turtle nesting beaches (Pendoley, 2012).

3.9 Artificial Lighting

Artificial lighting on VI is associated with the existing petroleum processing facilities and the supporting infrastructure (e.g. workshops, accommodation area, wharves). Santos WA monitors artificial lighting and the visibility of those lights from sensitive environmental receptor areas (e.g. marine turtle nesting beaches) in accordance with the Lighting Management Plan (Doc. Ref: EA-60-RI-153).

3.10 Conservation Reserves

As described in Section Error! Reference source not found., VI is part of the Lowendal Islands Nature Reserve (Reserve 33902) and is managed by the DBCA. All petroleum activities on VI are managed in accordance with lease 1902/100 and 2604/100.

VI and the marine areas of the port are excluded from any marine reserves. The nearest state marine reserves are the Barrow Island Marine Management Area and Montebello Islands Marine Park as indicated in Figure 3-4.


Figure 3-4: Regional Marine Habitats and Conservation Reserves


4 Project Description

4.1 Varanus Island Compression and Power Optimisation Project (VICPOP)

Overview

At the current time, gas and associated liquids flow under natural pressure from the wellhead platform through the onshore John Brookes (JB) slug catcher then to the inlet of the amine trains on VI. Declining JB reservoir pressure means that in the future there will no longer be sufficient natural pressure to maintain the required production flow rate. The VICPOP will compensate for the future decline in reservoir pressures.

The VICPOP involves the planning, design, construction/installation, pre-commissioning, commissioning and operation of additional natural gas compression equipment, power generation and ancillary facilities that are to be integrated with the existing ESJV gas plant. The VICPOP includes:

Two gas fuelled Solar Mars 100 gas turbine driven compressors, module based and including scrubbers, air cooled heat exchangers, gas/gas exchanger and JT gas cooling valves.

One gas fuelled Centaur 40 gas turbine driven electrical power generator.

One pipe rack module.

One electrical switch room.

One transformer compound and battery room.

Utilities upgrades including instrument air, and tie-in of demineralised water, fire water, power and data.

The compressors will discharge process gas at temperatures in excess of 100°C. Initial cooling of the gas will be achieved via air cooled heat exchangers which will typically drop the gas stream temperatures to between 35°C and 55°C depending on the ambient air temperature which has considerable seasonal variation.

Additional cooling of the gas stream is required to achieve the current ESJV gas plant inlet temperature of 26°C to 30°C and this cooling of the VICPOP gas stream is provided in two ways:

A gas/gas heat exchanger that cools the compressor discharge stream through cross-exchange with the incoming gas stream from the slug catcher.

Expansion of the over-pressurised compressor discharge stream through the JT valves thereby decreasing its temperature.

Following cooling, the gas stream may enter the ESJV gas plant’s amine plant to remove entrained

CO2 and then the existing gas trains for dehydration and hydrocarbon dew pointing to achieve sales gas specification.

The VICPOP also requires a new electric power generator (11 kV) to meet the increased electrical loads associated with the new compressors and their utilities. The new generator will also provide additional spinning reserve to be shared with existing facilities such that the ESJV gas plant generators can effectively backup the new VICPOP generator and vice versa.

4.2 Gas processing and Equipment Overview

As applicable to the ESJV gas plant, a simplified process flow diagram for the existing gas processing facilities and the future (i.e. VICPOP) gas processing, including condensate and produced water, is provided within Figure 4-1 and Figure 4-2 respectively.


Figure 4-1: ESJV Gas Plant Process Block Diagram (Existing)

Figure 4-2: ESJV Gas Plant Process Block Diagram (Post VICPOP)

In relation to the block diagram as per Figure 4-2, reference should be made to Appendix 2 where additional detail by way of process flow diagrams for the intended VICPOP works, the subject of the WAA, have been included.

Data sheets for the VICPOP’s turbine powered compressors and turbine powered generator have also

been included within Appendix 3.


Slug Catcher

Hydrocarbons from the JB offshore pipeline enter the ESJV gas processing plant via the slug catcher that serves to separate condensate and produced water from the raw gas stream. The slug catcher is the buffer between the supply gas pipeline and the downstream processing plant. The slug catcher is a single vessel designed for three-phase separation, with the outlet feed gas stream currently directed into the amine CO2 exchange unit within the ESJV gas plant. Within the slug catcher, the produced water is directed under level control to the produced water treatment system and gas condensate is routed to the condensate stabilisation system.

The VICPOP will not require any capacity upgrade or modification to the slug catcher vessel however some downstream pipework modifications will need to be undertaken so that raw gas may be directed into the new VICPOP process facilities.

During the late life phase of the VICPOP, new condensate pumps will need to be installed downstream from the slug catcher to assist with removal of condensate liquids. The inclusion of the condensate pumps is considered within the Pipeline Licence variations as described in Section Error! Reference source not found..

Gas Processing Trains

The existing two ESJV gas plant processing trains have a total capacity of 240 TJ/day (218 MMSCFD) sales gas production, including CO2 removal, dehydration, mercury removal, dewpoint control, and gas compression equipment as described below.

CO2 Removal

The JB raw gas stream contains approximately 5.8% CO2. The removal of CO2 is achieved by contacting the gas stream with lean liquid amine in a counterflow arrangement within a contactor column. The amine progressively enriches with CO2 as it progresses down the column and the enriched amine is then stripped back to a lean state within a re-boiler and recirculated under pressure back to the contactor column. The CO2 removed within the re-boiler is vented to atmosphere.

The existing amine plant will not require substantial modification other than pipework tie-ins to receive gas from the VICPOP works area.

Gas Dehydration

Following discharge from the amine plant, the gas is dehydrated (removal of any residual moisture) to prevent ice or hydrates forming in the downstream cryogenic equipment and to achieve the sales gas specification required for gas export into the Dampier to Bunbury Natural Gas Pipeline (DBNGP). Dehydration occurs in a triethylene glycol dehydration unit.

The VICPOP will not require any capacity upgrade or modification to the existing gas dehydration equipment.

Mercury Removal

Traces of mercury may occur in the supply gas stream which has the potential to cause degradation of aluminium used within the downstream gas processing equipment. A mercury guard bed downstream of the dehydration unit removes any trace of mercury from the gas stream. Entrained dust is also removed by a particulate filter located downstream of the mercury guard bed.

The VICPOP will not require any capacity upgrade or modification to the existing mercury guard bed.

Hydrocarbon Dewpoint Control

The hydrocarbon dewpoint of the treated gas is reduced to satisfy the DBNGP specification limit using an auto-refrigeration process comprising gas/gas heat exchange via a JT valve and a low-temperature separator. The hydrocarbon liquids separated out from this process are directed to the condensate stabilisation train.


The VICPOP will not require any capacity upgrade or modification to the existing hydrocarbon dewpoint control equipment.

Compression

Treated gas from the dewpoint control equipment is directed to the ESJV gas plant’s sales gas

compressors to increase the gas pressure for gas delivery to the mainland and export into the DBNGP. Sales gas compression is currently provided by three Solar Taurus 60 gas fired turbine driven compressors and one Solar Mars 100 gas fired turbine driven compressor.

The VICPOP will not require any capacity upgrade or modification to the existing gas compression equipment.

4.3 Condensate Processing

Condensate recovered from the JB slug catcher, hydrocarbon dewpoint control and the proposed VICPOP works is stabilised and stored prior to shipping load-out.

Stabilisation

Condensate stabilisation is required to reduce the vapour pressure of the hydrocarbon condensate so that it meets the Reid vapour pressure. Liquid hydrocarbons captured in the slug catcher and hydrocarbon dewpoint low temperature separator are sent to a stabilisation train consisting of a condensate stabiliser re-boiler, stabiliser column, surge drum, pre-heater, run-down cooler, condensate cross exchanger and overheads compression package.

Gas and wet vapour from the stabiliser feed surge drum and stabiliser column within the condensate stabilisation process is recycled back into the gas process by an overheads compressor associated with the stabilisation train.

The VICPOP does not require any change to the condensate stabilisation process equipment.

Storage

Crude oil and stabilised condensate is currently stored on VI within three storage tanks each of 250,000 barrels (39,750 m3) capacity.

The VICPOP does not require any change to the petroleum liquids storage capacity.

The bund area will maintain the required secondary containment volume of not less than 110% (43,720 m3) of a single crude oil storage tank (39,750 m3).

Shipping Load-out

Liquid petroleum in the form of stabilised condensate and crude oil is currently discharged from the storage tanks to offshore tankers via three diesel powered shipping pumps.

The VICPOP does not require any change to the existing liquid petroleum discharge system.

4.4 Existing and Additional VICPOP Utilities

The ESJV gas plant incorporates existing utility systems as described below. Where the VICPOP requires an upgrade to the existing utility systems, this has been identified.

ESJV Flare System

The ESJV gas plant’s flare system is provided to accommodate and safely dispose of pressure safety valve and blowdown valve discharges, operational de-pressuring and any other means by which hydrocarbons may be vented from within the plant. The plant relief and blowdown system or flare system comprises a staged ground flare and high pressure elevated flare.


The ESJV gas plant’s high pressure (HP) elevated flare is required for the safe disposal of large relief

cases, plant blowdown and other emergency flaring events. This system is capable of handling a full plant-wide blowdown reducing pressure from high trip pressure to an acceptably safe pressure in approximately 15 minutes.

The ESJV gas plant’s ground flare is used for operational flaring and is fully shielded within an

insulated enclosure to minimise the emissions of visible light from the gas plant.

A flare knock-out drum is provided upstream of the elevated and ground flares to remove liquids. All low flow (low pressure) releases are directed to the ground flare. As the flare system load increases resulting in an increase in flare system backpressure, a pressure control valve opens to re-direct flow to the elevated HP flare.

Pilot burners for the flares are fired by fuel gas and a back-up fuel system, consisting of a dedicated bottled propane supply, is also provided.

The VICPOP works will not cause significant additional flare loads or frequency of flaring. The VICPOP will require pipework tie-in to the existing flare system.

Fuel Gas

Fuel gas derived from existing gas processing will be required to supply the VICPOP turbine drivers for gas compression and power generation.

Fuel gas for the VICPOP turbine driven equipment will be sourced from the existing sales gas suction header at a rate of 58,000 tpa at an ambient temperature of 11oC and assuming 100% load.

The VICPOP does not require any change to the existing fuel supply system other than tie-ins to the existing fuel gas pipework.

Seal Gas

Seal gas for the VICPOP inlet compressor dry gas seals will be taken from the sales gas discharge header.

Hot Oil System

The VICPOP turbine powered compressors and generator as initially installed will not include waste heat recovery units attached to the turbine exhausts; although provision (i.e. future space) has been made for their installation if required.

Produced Water Treatment

Processing of the JB gas stream results in saline water as a by-product, known as produced formation water (PFW). The PFW removed from the slug catcher is treated further to remove hydrocarbons via water degassing vessels (or degassers) that remove dissolved gas from the PFW and act as a pressure break vessel between the slug catcher and the PFW storage tanks. PFW from the degassers is then routed to existing produced water storage tanks that have fixed roofs. The PFW within the tanks has a fuel gas blanket which vents to the flare system. The tanks have the facility to skim hydrocarbon condensate, with the skimmed condensate directed to the stabilisation train. PFW is then fed to existing water disposal pumps that return the water to depleted petroleum reservoirs.

The VICPOP does not require any change to the existing PFW treatment or disposal systems other than piping tie-ins to accept produced water from VICPOP scrubbers.

VICPOP Instrument Air

Additional instrument air demands associated with the VICPOP requires a supplemental instrument air source to be provided by a new instrument air package comprising electric-motor-driven compressors, with dual-bed adsorption driers to dry the air and dedicated instrument air receivers. The new package will also act as a back-up instrument air supply for the existing VI instrument air system via a cross-over piping tie-in to the existing plant.


Demineralised and Potable Water

Demineralised potable water is a utility supply to the VICPOP works area for the purposes of on-line turbine water wash as a maintenance requirement. As an on-line system, washing water is vapourised in the cleaning process and vented to atmosphere via the turbine’s exhaust stack. Normal potable water is required within the VICPOP works area for the purposes of safety showers.

The VICPOP does not require any change to the existing demineralised or potable water supply system other than pipework modifications to achieve tie-in to the existing pipework.

Fire Water

For the purposes of fire mitigation, the VICPOP works area will require the installation of foam ejecting monitors linked into the existing fire water reticulation system.

The VICPOP does not require any change to the existing fire water supply system other than pipework modifications to achieve tie-in to the existing pipework.

Power Generation and Distribution

To support the additional VICPOP electric load, the existing VI power generation will be supplemented by the addition of one new gas fuelled turbine driven generator (Solar Turbines Centaur 40) rated at 3.5 MW at 11 kV. The turbine combustion process incorporates dry-low NOX burners using Solar Turbines proprietary SoLoNOx technology, a summary data sheet for which has been included within Appendix 3.

Electrical power generated at 11 kV will be connected to the existing HV switchboard via above ground cables within cable trays and conduits. Transformers will be used to step the power down for distribution at 415 volts alternating current for use in the VICPOP works area.

4.5 Supporting Infrastructure and Services

Buildings

The VICPOP works area will include a number of buildings to support operations including:

An electrical switchroom building.

A packaged instrument air enclosure.

A battery room.

Existing buildings on VI will also be used to support the VICPOP works, including the control building, workshop, stores, kitchen and mess, accommodation and recreation facilities.

Roads

The VICPOP will require the upgrade to existing roads on VI for the purposes of construction support. Upgraded roads will be a minimum of 8 m wide and based upon the typical geometry and axle weights associated with a fully laden single trailer heavy vehicle. Roadside barriers and bollards will be provided on the road shoulders where there is the potential for damage to adjacent equipment or essential services.

Roads within the VICPOP works area will be unpaved during module delivery and final surface being interlocking pavers.

Concrete Batching Plant

An existing concrete batching facility on VI is used for small-scale works required for the maintenance of facilities and infrastructure. For the VICPOP, the existing concrete batching facility will be used. On-site concrete and grout batching will be required for works where precast concrete is not feasible such as minor foundations, footpaths and blinding.


Maintenance on the existing concrete batching facility will be undertaken prior to the VICPOP preparatory works (not subject to this WAA). The facility is operated in accordance with the Environmental Protection (Concrete Batching and Cement Product Manufacturing) Regulations 1998.

Lighting

Lighting on VI is an important issue largely because of the potential impacts to marine turtles. Santos WA has prepared a Lighting Management Plan (Doc. Ref: EA-60-RI-153) for operations on VI, including construction activities, which addresses the requirements of EPA Environmental Assessment Guidelines No.5 (EAG No. 5): Environmental Assessment Guideline for Protecting Marine Turtles from Light Impacts (EPA, 2010). A summary of the key management commitments in the Lighting Management Plan is as follows.

4.5.4.1 VICPOP Construction Lighting

VICPOP construction works are to be undertaken during daylight hours only except for non-destructive examination (NDE) work (e.g. radiography and hydrotesting) which is required to be done at night for safety reasons and also the performance of leak testing as may be undertaken during VICPOP pre-commissioning work. Lighting associated with these activities will be local (i.e. no floodlighting) and be adequately shielded at all times.

4.5.4.2 Lighting Required for VICPOP Operations

The provision and use of permanent artificial lighting is required for safety and operational reasons as the VICPOP works will operate on a 24 hour per day basis.

The permanent lighting systems as required for the VICPOP works are presented within the VICPOP Process Facility Outdoor Illumination Plan (Doc. Ref: JB-10-RE-044) that has been developed in accordance with EAG No. 5 and subjected to an independent review and assessment conducted by expert turtle consultant Pendoley Environmental. Key management measures outlined in the illumination plan as applicable to the VICPOP works area are as follows:

Lighting will be switched off unless lights are required for routine inspections (the process facilities within the VICPOP works area will normally be unoccupied at night).

Lighting will be limited to 50 mins total on time during operations to ensure a predominantly lights off philosophy.

The electrical switch room has been designed without windows.

Manual light switches will be located to enable operators to turn lights on/off.

VICPOP facility lights will be monitored with timing alarms and controlled via a constantly manned central control room (i.e. the VI Control Building).

Filters (typically amber) will be fitted to all fluorescent tubes to minimise energy transmitted in wavelengths below 560 nanometers (light in the 450 to 500 nanometer range is most visible to turtles). Use of fluorescent tubes is required for safety reasons due to their instantaneous lighting characteristics unlike alternatives that have an appropriate wavelength but an unacceptable warm-up period (e.g. high pressure sodium lights).

Diffusers and shields will be fitted to luminaries in elevated locations to prevent direct light (i.e. light fixture filament) visibility from turtle nesting beaches.

Lights will be installed horizontally to the floor to contain the light within the confines of the VICPOP works area.

The facilities within the VICPOP works area have been modelled to project and illustrate the extent of direct light.


4.5.4.3 Management Commitments in Respect of VICPOP Lighting

A summary of the key management commitments in the existing VI Lighting Management Plan is as follows:

Annual monitoring of turtle nesting activities by specialist marine scientists.

Annual lighting audit during turtle breeding season.

Implementation of lighting design features during construction and operation.

An ongoing review of existing operational lighting to ascertain where light emissions can be reduced.

A robust VI induction procedure to ensure that construction personnel are aware of lighting management needs.

Potable Water Supply

Groundwater is the sole source of potable and near potable water throughout the construction and operations phases of the VICPOP. Water will be obtained from the existing bores located within the VI lease and processed through reverse osmosis (RO) and flash distillation units. A temporary reverse osmosis (RO) plant was installed to support VICPOP construction work in circa 2014 under W5518/2013/1 and remained on-site as a back-up system for VI operations requirements.

The existing potable water supply will also be utilised to supply water to the safety showers required within the VICPOP works area.

The potable water supply also makes provision for the supply of demineralised water as required within the process facilities for the purposes of CO2 removal (i.e. within the existing amine plant) and for the new turbine on-line water washing systems required for the VICPOP. Potable water required for the VICPOP will not add significantly to water consumption due to the infrequent use of the turbine water washing systems.

Stormwater and Site Drainage

The VICPOP works area can be expected to experience periods of torrential rain during cyclones and major storm events. The stormwater management system within the VICPOP works area will consist of a series of drains and treatment designed to satisfactorily dispose of the following water sources:

Clean stormwater from non-process areas.

Contaminated stormwater from within concrete sumps and skid floor plates associated with the VICPOP process equipment.

The process facilities drainage scheme comprises a system of impermeable concrete sumps, closed drains and proprietary oily water separation hardware within the works area. The discharge of the closed drain system is further treated by passing the drainage products through a proprietary Humeceptor oily water separator (OWS) designed to capture and retain total suspended solids down to 10 µm and remove free oils from the inlet stream to the performance described in


Table 4-1.

Treated discharge water will be piped to an existing retention basin to the west of the VICPOP compressor modules. The retention basin operates as an infiltration and evaporation basin, however if sufficient water run-off quantities are generated by a storm event, discharge will occur from the pond into the existing drainage lines on the lease land. The retention pond is sized to allow settlement of and to prevent carry over sediment prior to discharge into existing drainage lines within the Santos WA lease area.

The open drain system for stormwater run-off similarly directs flow to a separate proprietary Humeceptor prior to flowing to the same retention basin.


Table 4-1: Performance Characteristics of the Humeceptor OWS

Upstream TPH Concentration1 (ppm)

Downstream TPH

Concentration2 (ppm) % Removal efficiency3

48 1.3 97.2%

1,946 8 99.6%

Notes:

1. Santos WA expects the upstream concentration of Total Petroleum Hydrocarbons (TPH) entering the Humeceptor to vary between approximately 50 ppm (routine operations) and 2,000 ppm (non-routine operations).

2. Downstream concentration is at the Humeceptor outlet.

3. Removal efficiencies are based upon continuous full (maximum) treatment flow rate to reflect relatively extreme field conditions.

4. The concentrations provided as ppm (by volume) are offered as the industry standard rather than mg/L that has inherent difficulties when dealing with upstream and downstream flows comprising variable specific gravities i.e. water and TPH.

Sewage

Works Approval W6266/2019/1 has been issued for the construction of a 72 m3 per day Sewage treatment Plant (STP). The VICPOP does not require any change to the STP or effluent disposal system.

4.6 Pre-commissioning and Commissioning Activities

The pre-commissioning activities will overlap with the later stages of the VICPOP construction activities and will involve instrument and valve testing and utility start-ups. Once site construction, module installation and pre-commissioning activities are completed, the VICPOP plant including all associated facilities and utilities, will be commissioned. The purpose of commissioning is to confirm the proper functioning of the VICPOP’s major components and to detect any potential leaks and

problems so that any adjustments may be made prior to gas production through the VICPOP plant.

During the commissioning phase, which is estimated to take up to 90 days, turbine exhaust stack emission monitoring will be undertaken as described in Section 8.1.5.

4.7 VICPOP Work Phases and Timing

The timing of the activities associated with the VICPOP is subject to receipt of all government approvals, contractor availability and weather. Indicatively, activities described as a component of this WAA will commence in 1 January 2020 and continue until Q2 2021 as shown in Table 4-2.

Table 4-2: Indicative Timing for VICPOP Activities

Work Phase Activity Commence Conclude

1 Installation of the process facility modules and associated infrastructure.

1 January 2020

Q4 2020

2 VICPOP Commissioning. Q1 2021 Q2 2021


5 Stakeholder Consultation

Santos WA considers that the consultation conducted has been adequate and has taken into consideration all feedback necessary for effective planning of the works associated with the VICPOP.

5.1 Santos WA Stakeholder Consultation Strategy

As stated in the Santos WA Environmental Management Policy the company is committed to work proactively and collaboratively with our stakeholders and the communities in which we operate.

The operating presence of Santos WA (i.e. the company’s gas processing facilities on VI) and exploration and development activities on WA’s North West Shelf, ensures that communication is

regular with numerous cohorts on multiple occasions, including most stakeholders potentially affected by these activities.

Santos WA maintains a comprehensive stakeholder database, which is overseen by a dedicated Stakeholder Coordinator. Stakeholders in the database have been identified through the following mechanisms:

Review of legislation applicable to petroleum and marine activities.

Identification of marine/land user groups and interest groups active in the area (e.g. the recreational and commercial fisheries, other oil and gas producers).

Active participation in industry bodies (e.g. the Australian Petroleum Production and Exploration Association (APPEA).

Records from previous consultation activities in the area as conducted by Santos WA from time to time.

5.2 Stakeholder Identification

Varanus Island is a remote offshore island with land-access restrictions because it is a gazette nature reserve and has operating petroleum production facilities. As such, relevant stakeholders for the proposed VICPOP works are largely restricted to Commonwealth and State government authorities responsible for the environment and also matters of development planning.

Various consultation methods (e.g. meetings, emails, phone conservations, public invitations and advertisements) have been used by Santos WA and government authorities to engage relevant stakeholders that have an interest in the VICPOP works.

Table 5-1 provides a summary of the consultations relevant to the WAA as conducted between Santos WA3 and interested stakeholders, which includes the identified stakeholders and their interests and Santos WA’s assessment of the consultation matters.

Table 5-1: Works Approval Consultation Summary

Stakeholder Consultation Topic Consultation Assessment

Department of Mines and Petroleum (DMP; now the Department of

Pipeline Licence Variations (April 2013)

The DMP approved variations to Petroleum Pipeline Licence PL12 (No. STP-PLV-0024) and PL29 (No. STP-PLV-0025) for the proposed activities. A condition of the granted variations is that an environmental management plan is

3 Refer to Table 1-3 regarding the change from Apache to Santos WA. Historical consultation was undertaken under Apache (now Santos WA). Stakeholders have been advised of the company name change.



Mines, Industry Regulation and Safety, DMIRS)

required to be submitted to the DMIRS for assessment and approval under the Petroleum Pipelines Act. Santos WA will submit a Construction Environmental Management Plan (CEMP) bridging to the VI Hub Operations EP for the VICPOP works. This consultation matter is ongoing and construction will not commence without the relevant approval.

Department of Environment and Conservation (DEC; now the Department of Water and Environmental Regulation, DWER)

Works Approval Requirements (October 2012 and current)

The DEC advised that a Part V Works Approval is required for the construction work based on the submitted application enquiry form. This WAA has been lodged electronically with the DWER. Works Approval conditions will be managed in accordance with the VICPOP Commitments Register (Doc. Ref: JB-10-HI-001). This consultation matter will be complete on DWER’s

acceptance of the WAA.

Works Approval Air Modelling (October 2012)

On the basis of air modelling briefing note submitted by Santos WA3, the DEC agreed with the conclusion that the emissions from the operation of the VICPOP works are not going to significantly affect regional ozone concentrations and that it should therefore be acceptable to proceed with the modelling of local impacts only. This consultation matter is considered to be complete.

Lighting Management Plan for VI (June 2013)

In accordance with conditions of the Santos WA lease, the VI Lighting Management Plan (Doc. Ref: EA-60-RI-153) was submitted to the DEC. This plan relates to existing operations and also to proposed future developments on VI. The activities described within the Works Approval application meet the requirements of the VI Lighting Management Plan, as demonstrated in the VICPOP Process Facility Outdoor Illumination Plan (Doc. Ref: JB-10-RE-044). This consultation matter is considered to be complete.

Department of Sustainability, Environment, Water, Population and Communities (SEWPaC; now the Department of the Environment and Energy, DOTEE)

EPBC Act Referrals (November 2012)

Santos WA (then Apache) had consulted with SEWPaC (now DOTEE) on EPBC Act matters since November 2012. SEWPaC’s interests relate primarily to the effects of construction noise and vibration emissions on breeding wedge-tailed shearwaters, and operational lighting emissions on nesting marine turtles and emerging hatchlings.

As such, a referral (Referral 1) that deals specifically with noise and vibration associated with the VICPOP works area was submitted in 2013. A referral decision as ‘Not controlled if

undertaken in a particular manner’ was received. This consultation matter is considered to be complete.



Santos WA (then Apache) had also submitted to SEWPaC (now DOTEE) a referral (Referral 2) that deals specifically with lighting matters associated with VICPOP construction and operations that may affect marine turtles; and to a lesser degree, migratory seabirds. The referral was submitted in 2013. A referral decision as ‘Not controlled if undertaken in a particular manner’ was received. This consultation matter is considered to be complete.

Environmental Protection Authority (EPA)

Environmental Impact Assessment Requirements (March 2013)

Santos WA referred the proposed VICPOP works to the EPA under Section 38 of the EP Act. The referral was open for public comment. Based on the EPA’s assessment of the referral and public

comments, the decision ‘Not Assessed - Public Advice Given’ was determined. In summary of the

public advice given, the EPA did not consider the potential environmental impacts to be significant and was of the opinion that the activities could be appropriately managed through the DMIRS and DWER. This consultation matter is considered to be complete.

6 Environmental Risk Assessment

Environmental risk assessment refers to a process where hazards are quantitatively and/or qualitatively assessed for their impact on the environment (physical, biological, and socio-economic) at a defined location.

While the assessment is as objectively based as possible, working knowledge of VI gained by Santos WA over many years of oil and gas production and export means that the overall assigning of significance to a particular issue or impact also takes into consideration this subjective knowledge in conjunction with the hazard identification process as undertaken for the proposed VICPOP works.

6.1 Environmental Risk Assessment Method

Background

As with any major activity or development that Santos WA undertakes on VI, the hazard identification process is an integral part of analysing the known and potential environmental, engineering, safety and social hazards as may arise during the VICPOP works. By analysing the risks of these hazards during the early design stage of the development, any hazard that is deemed an unacceptable risk can and must be designed out or mitigated for as part of the engineering design process.

Risk assessment is defined as the process of determining the frequency of occurrence of an event and the probable magnitude of adverse effects – economic, human safety and health, or ecological – over a specified period of time (Kolluru, 1994).

The process of identifying the risks and likelihood of given events and the magnitude of their effects consists of several interrelated steps, including:

Risk identification – recognising that risks exist and identifying their characteristics.

Risk determination – determining the characteristics of risks either qualitatively or quantitatively. These may include frequency, magnitude, spatial scale, duration and intensity of adverse consequences.


Risk control – designing to minimise the risk and setting up a management system with standards, procedures, guidelines and so forth to decrease or eliminate risk and to review performance.

The identification of environmental hazards is the first step of the environmental impact assessment process. Hazard identification is undertaken to identify all the environmental hazards associated with a project likely to occur from routine and accidental activities and to assign a potential risk to each hazard. It is undertaken in line with the Australian risk management standard AS/NZS ISO 31000:2009.

Hazard Identification and Assessment

A prehazard identification meeting is a method of improving the effectiveness of hazard identification workshops. The main purpose is to ensure that key issues and project-specific matters are appropriately prioritised. The objectives of the meeting are to:

Review project details and ensure key information is presented at the hazard identification workshop.

Agree on the scope and objectives for the workshop.

Identify any preparations required for the workshop.

A prehazard identification meeting for the VICPOP works was held in late June 2012. The environmental hazard identification workshops for the VICPOP works took place during two sessions in July and September 2012. Each workshop was attended by a multi-disciplinary team of up to nine people, including engineering and environmental representatives from Santos WA and was facilitated by the independent environmental consultancy Oracle Risk Consultants (Oracle). The outcomes of the workshop held in 2012 were revived in 2019 during the development of this WAA and deemed to be

sufficient.

Some attendees at the workshop had detailed gas plant design and process knowledge from experience in designing and operating gas facilities, while others had extensive knowledge of marine and terrestrial ecology and/or the environmental approvals process through previous experience in managing the development of new oil and gas processing facilities on VI.

The objectives of the hazard identification workshop were to:

Identify potential environmental hazards associated with the VICPOP works.

Identify potential risks associated with the identified hazards.

Rank each hazard in terms of its likelihood and severity.

Determine whether each hazard has the potential to impact the environment.

Where necessary, propose actions or recommendations to improve the design and safeguards to prevent the identified hazards or mitigate them to as low as reasonably possible (ALARP).

The environmental HAZID and risk assessment was carried out by Santos WA to feed into the design of the gas processing plant and as part of the identification and development of environmental management controls. A summary of the HAZID outcomes for VICPOP construction and for VICPOP operations is provided in Section 7 and Section 8.

Risk Ranking

Environmental risk ranking is determined by a combination of the likelihood of the hazard occurring and the severity of its occurrence. The workshops in 2012 used an Apache risk matrix, which has been superseded by the Santos WA risk matrix (refer to Appendix 4). Hence, risk rankings were reviewed and re-mapped in the preparation of this WAA and now reflect the current Santos WA risk matrix.

6.2 Environmental Risk Assessment Summary

Recommendations and actions from risks identified in the risk impact and assessment workshops, were reviewed, and where appropriate incorporated into facility designs, to substitute or reduce the


identified risks to acceptable and as low as reasonably practicable (ALARP) levels. The recommendations and actions are summarised within the following sections that relate to VICPOP construction activities and also VICPOP operations.

7 Emissions, Discharges and Wastes during Construction

Emissions, discharges and wastes arising from construction within the VICPOP works area will be managed in accordance with the CEMP that will bridge to the VI Hub Operations EP and the requirements as identified within the VICPOP Commitments Register (Doc. Ref: JB-10-HI-001).

7.1 Atmospheric Emissions

Emissions Description

Construction activities are likely to result in a temporary increase in atmospheric emissions (i.e. combustion) across the VICPOP works area. Combustion emissions will result from the use of heavy machinery and plant equipment and increased use of vehicles required for construction workforce transport.

Dust emissions from heavy machinery and vehicle movements are expected to be greatest during the construction phase and are likely to vary depending on the construction activity and the prevailing wind conditions.

Management Controls

A range of measures to control atmospheric emissions during construction will be implemented including the following:

Minimising areas to be disturbed.

Watering of unsealed roads, access tracks, work areas and soil stockpiles as required.

Application of approved active dust control products.

Maintaining low traffic speed limits.

Reduction of traffic movements (e.g. use of pre-cast concrete rather than in-situ concrete which is more vehicle intensive).

Minimisation of on-site concrete batching through the use of off-site pre-cast concrete.

Controlling concrete batching activities in line with the Environmental Protection (Concrete Batching and Cement Product Manufacturing) Regulations 1998.

Maintenance of mobile equipment to ensure combustion processes are within specification.

Risk Assessment

Combustion emissions arising from VICPOP construction works will be insignificant compared to existing combustion emissions from the power generation and the petroleum processing facilities on VI. The measures to be implemented for the control of air-borne dust will ensure that there will be no significant increase in dust levels during the VICPOP works. Mangroves will continue to be monitored as per existing operations and dust levels managed accordingly.

Therefore, in accordance with the Santos WA risk matrix the atmospheric emission risks during construction were assessed as being low and acceptable.

7.2 Noise and Vibration Emissions

Emission Description

Activities associated with heavy machinery, vehicles and other construction processes within the VICPOP works area will result in a temporary increase in noise emissions within the area.


Noise and vibration emissions are expected to include machinery operations and movement, the running of generators, potential load out of concrete from the existing concrete facility and equipment such as grinders used during the installation of piping and process equipment.

Management Controls

A number of measures to control noise and vibration emissions during construction will be implemented including the following:

Maintenance of mobile equipment to ensure equipment exhaust systems are operating as designed.

Limiting construction noise to daylight hours only thus reducing the impact on sensitive receptors (e.g. wedge-tailed shearwater nests within rookery areas) where fauna is active at night.

Risk Assessment

Noise emissions arising from VICPOP construction works will be insignificant compared to existing noise emissions from the power generation and the petroleum processing facilities on VI.

The measures to be implemented for the control of construction noise will ensure that there will be no significant increase in noise levels during the VICPOP works.

Although the operation of heavy machinery and vehicles has the potential to increase vibration levels above the ambient levels, the control measures to be implemented will ensure that vibration levels will be insignificant at the boundary of sensitive receptor areas.

The EPBC Act assessment (Referral 1) as summarised in Table 5-1 considered matters of noise and vibration on marine turtles and migratory seabirds and VICPOP construction activities will be managed accordingly.

Therefore, in accordance with the Santos WA risk matrix the noise and vibration risks during construction works were assessed as being low and acceptable.

7.3 Light Emissions


Construction activities may present light spill to sensitive environmental receptors (e.g. marine turtle nesting beaches). The vast majority of construction activities within the VICPOP works area are to be conducted in daylight hours.

As described in Section 4.5.4.1, VICPOP pre-commissioning work may require NDE and hydrotesting activities to be conducted at night for safety reasons. These pre-commissioning activities will be short in duration (i.e. hours to days) and if required during the turtle breeding season, localised lighting will be managed in accordance with the VI Lighting Management Plan.

Management Controls

A number of measures to control light emissions during construction will be implemented including the following:

Scheduling of construction work within daylight hours only to negate the need for artificial lighting (during the 1 August to 15 April Wedge-tailed Shearwater and turtle nesting season).

Pre-commissioning activities (NDE and hydrotesting) will be short in duration (i.e. hours to days).

Localised lighting as required for pre-commissioning activities will be managed in accordance with the VI Lighting Management Plan.

Use of localised and low level lighting only; with no use of lighting towers, for the essential pre-commissioning activities (NDE and hydrotesting).

Provision of light shields around the low level lighting to prevent light spill during pre-commissioning activities.


Risk Assessment

Light emissions arising from VICPOP construction works will be insignificant and therefore, in accordance with the Santos WA risk matrix the risks associated with light spill during construction works that may affect sensitive environmental receptors were assessed as being low and acceptable.

7.4 Discharges to Water

Discharge Description

Brine and reject water from the temporary desalination unit for the provision of construction support water for the VICPOP will be discharged at the existing VI brine discharge location.

The use of heavy machinery, vehicles and equipment may result in fuel and oil spills and leaks that can carry over to drainage lines in rainfall events or infiltrate into the water table (~7 m below the works area) (Refer to 7.5).

Run-off within the VICPOP works area from storm events has the potential to present sediment into drainage lines and ultimately near shore waters.

Management Controls

A number of measures to limit and prevent discharges to water during construction will be implemented including the following:

Discharges from the temporary desalination unit will be recorded and reported as part of normal operations on VI

Temporary drainage lines on the western boundary of the works area will incorporate silt traps and be directed away from sensitive receptors (e.g. wedge-tailed shearwater rookery).

Risk Assessment

The measures to be implemented for the control of surface water run-off will ensure that there will be no significant increase in sediment loads originating from the VICPOP works area.

Therefore, in accordance with the Santos WA risk matrix the discharge to water risks during construction were assessed as being low and acceptable.

7.5 Discharges to Ground


The use of heavy machinery, vehicles and equipment may result in fuel and oil spills (e.g. during refuelling) or lead to leaks resulting in a discharge to ground which may then cause surface water and/or groundwater contamination.

The VICPOP construction works will not require the use of abrasive blasting on site. All process module steelwork will be coated off-site as will the majority of the process pipework. Some localised coating application will be required during construction works and this may result in localised overspray to ground.

Management Controls

A number of measures to limit and prevent discharges to land during construction will be implemented including the following:

Any ground disturbance will be conducted a minimum of 7 m above the water table thereby negating potential groundwater impacts.

Maintenance of mobile equipment to ensure hydraulic lines and engine sumps are competent and without evidence of leaks.


Equipment fuels and lubricants to be stored outside the VICPOP works area and contained in accordance with the Dangerous Goods Safety Act 2004 and regulations and AS 1940 – The Storage and Handling of Flammable and Combustible Liquids.

Adherence to site procedures to manage all required refuelling activities.

Spill response procedures.

Provision of spill kits within the immediate VICPOP works area so that spills and leaks may be immediately cleaned up.

Machinery servicing (oil change and lubrication) to be conducted only within existing VI designated areas outside the VICPOP works area.

An on-going program of groundwater quality monitoring on VI which will be extended to include an additional monitoring well within the VICPOP works area.

The use of rotary devices for metal preparation rather than grit blasting (as source of ground contamination) for the purposes of substrate preparation prior to coating applications.

The use of screens and ground sheets to prevent paint spray contamination of the ground surface.

Risk Assessment

Discharges to ground arising from VICPOP construction works will be insignificant and therefore, in accordance with the Santos WA risk matrix, the risks associated with these discharges were assessed as being low and acceptable.

7.6 Solid Non-hazardous Wastes

Waste Description

Construction activities will produce quantities of scrap piping and metal, packaging and pallets, concrete and general construction waste materials. Domestic and putrescible waste will also be generated from the various construction workforces accommodated on VI.

Management Controls

A number of measures to manage solid non-hazardous waste resulting from construction activities will be implemented including the following:

Waste management will be accordance with Section 6.5 of the VI Hub Operations Environment Plan (Doc. Ref: EA-60-RI-186) and Santos WA’s Waste Management Plan (EA-60-RI-167).

Wastes will be segregated for the purposes of recycling where possible.

Wastes that may be incinerated on VI are to be segregated.

A site evacuation procedure, covering the requirement to secure solid waste storage areas, in the event of an approaching cyclone.

All wastes arising from construction within the VICPOP works area that are to be exported from VI are to be appropriately disposed of at a licensed onshore waste disposal facility on the WA mainland in line with regulatory requirements.

Bulk waste storage bins will have hinged lids fitted or will be covered to prevent the creation of wind-blown debris.

Risk Assessment

On the basis that existing solid waste management processes on VI are effective the risk of non-compliant storage and handling of solid waste originating from VICPOP construction works is considered to be insignificant and therefore, in accordance with the Santos WA risk matrix, the risks associated with solid waste management were assessed as being low and acceptable.


7.7 Liquid Non-hazardous Wastes

Waste Description

Sewage and greywater will be produced throughout the construction works however it should be noted that the VICPOP will not require the accommodation capacity on VI to be increased above existing levels.

Localised hydrotesting of VICPOP pipe spools will require disposal of hydrotest water (<10 kL).

Management Controls

A number of measures to manage non-hazardous liquid waste resulting from construction activities will be implemented including the following:

Portable toilet and ablution facilities, with integrated effluent holding tanks, will be provided to manage sewage produced in the vicinity of the construction site, and their contents will be collected and disposed of through the sewage treatment plant on VI which is managed in accordance with Section 6.6 of the VI Hub Operations Environment Plan (Doc. Ref: EA-60-RI-186).

Greywater originating from the VI accommodation facilities will be processed through the existing waste water plant.

Only potable water will be used for hydrotesting without the use of biocides or oxygen scavengers and therefore will not require a controlled disposal method.

Risk Assessment

On the basis of the proposed mitigation measures the risks associated with liquid waste management during construction were assessed as being low and acceptable.

7.8 Hazardous Wastes

Waste Description

Hazardous waste will be generated throughout the construction phase of the VICPOP. Typical hazardous wastes from construction will include; solvents, waste paints, oils and used oil filters, batteries, machinery and vehicle wash-down products and cladding insulation wastes.

Wash-down products from the concrete batching facility and agitator trucks will be produced.

Management Controls

A number of measures to manage hazardous materials and wastes resulting from construction activities will be implemented including the following:

Santos WA has adopted the National Code of Practice for the Storage and Handling of Workplace Dangerous Goods (2001) as a Company standard for workplace control. This standard is applied to all Santos WA work sites to the extent that prevailing regulations are not contradicted.

All hazardous wastes (e.g. solvents, paints, fuel, oils and used filters and batteries) to be managed and disposed of in accordance with Santos WA’s Waste Management Plan (EA-60-RI-167).

Waste paints, solvents and chemicals are to be stored in suitable containers within a bunded area (or temporary bunding such as pallet bunds) and hardstand areas. Storing chemicals in bunded and hardstand ensures that spills or leaks from chemical storage areas can be contained or isolated and thus their entry into the environment can be restricted.

Maintain personnel access controls for all dangerous goods and hazardous waste storage areas.

A site evacuation procedure, covering the requirement to secure liquid storage areas, in the event of an approaching cyclone.

Ensure spill kits are available and strategically located to allow easy access to and the immediate clean-up of minor spills and leaks.


Conduct regular inspections and checks to ensure that the integrity of bunding and storage vessels are maintained and repairs undertaken for any leakages observed.

Maintain relevant records including material safety data sheets (MSDS) and database (Chem-Alert) records.

Ensure that dangerous goods are stored in compliance with the Australian Dangerous Goods Code and the relevant segregation charts. Incompatible chemicals are to be segregated to reduce the risks associated with reactions that may occur between non-compatible chemicals.

Washdown products originating from vehicles, machinery and equipment will be contained within the existing bund area allowing evaporation to take place.

Washdown products from the concrete batching facility and trucks will be contained within dedicated lined retention basins, settled out then desiccated by evaporation.

Risk Assessment

The control measures to be implemented for the management of hazardous wastes associated with the VICPOP works indicate that the ALARP condition for storage and handling will be achieved.

Therefore, in accordance with the Santos WA risk matrix the risks associated with hazardous waste management during construction were assessed as being low and acceptable.

8 Emissions Discharges and Wastes during Operations

Emissions, discharges and wastes arising from VICPOP operations will be managed in accordance with the CEMP bridging to the current approved VI Hub Operations EP (Doc. Ref: WA-60-RI-186 VICPOP Commitments Register (Doc. Ref: JB-10-HI-001) during the VICPOP commissioning phase (i.e. introduction of hydrocarbons) and thereafter in accordance with the VI Hub Operations EP and the DWER operating licence.

8.1 Atmospheric Emissions (Combustion)


8.1.1.1 Combustion Emissions

VICP turbine operations will result in the release of atmospheric emissions including greenhouse gases and other combustion wastes. These emissions will include nitrogen oxides (NOX as NO2), traces of sulphur dioxide (SO2), traces of carbon monoxide (CO), and also carbon dioxide (CO2). Existing VI emission points together with the three additional emission points that are the subject of the WAA are as indicated in Appendix 1.

Specific VICPOP process equipment that is the subject of the WAA that will become additional emission sources under normal operations include:

Two gas fuelled Solar Mars 100 (10.5 MW) gas turbine driven compressors.

One gas fuelled Centaur 40 (3.5 MW) gas turbine driven electrical power generator.

8.1.1.2 Seal and Vent Emissions

Routine emissions from the VICPOP works will include cold venting from the new compressor dry gas seal primary and secondary vents. Due to the relatively insignificant volumes of emissions vented, these discharges were not included within the modelling scenario (Section 8.1.4).


8.1.1.3 Non-routine Conditions Emissions

Non-routine conditions within the ESJV gas plant can lead to significantly increased emissions for short periods of time. In particular, if one or more processing trains must be shut down, then the process gas inventory must be routed to the flares for disposal, leading to high flare emissions. The ESJV gas plant blowdown takes approximately 15 minutes from high operating pressure to safe low levels. Where possible, the occurrence of continuous flaring and venting is avoided.

The flaring condition was not addressed in the VICPOP Air Quality Assessment (Doc. Ref: JB-10-RI-014; refer to Section 8.1.4) since the ESJV gas plant is an existing facility and within which, the VICPOP will result in the incorporation of two additional turbine powered compressors and a single generator to maintain capacity. Emissions from upset conditions will not change beyond those previously modelled (SKM, 2008) as there is no increase in production capacity.

Minor flaring will may be required during the introduction of hydrocarbons as required for VICPOP commissioning. Emissions levels via the existing ESJV flare system will be only slightly elevated due to the relatively small containment volumes within the VICPOP process pipework.

8.1.1.4 Fugitive Emissions

Some minor to insignificant fugitive emissions, due to leakages of the product gas from the VICPOP process equipment, may be expected. VICPOP drains for PFW and residual condensate will be closed to prevent atmospheric emissions.

Management Controls

Measures to control atmospheric emissions during operation of the turbine powered equipment (Solar Mars 100 compressors and Centaur 40 generator) include the following:

Low sulphur fuel (<8 ppm) to be used for the turbines.

Selection of dry-low NOX burners within each turbine using Solar Turbines proprietary SoLoNOx technology to reduce NOX (as NO2) combustion emissions4.

Specification of flue gas monitoring points for the turbine powered machines5.

Selection of rotating machinery such that the load characteristics for the machines are predominantly elevated thus facilitating performance of the SoLoNOx technology.

High utilisation (>95% annually) for operation of the turbine powered machinery thereby reducing increased emissions that may be expected during non-steady state conditions (start-up and shut-down).

Selection of compressor and generator engines as turbine equipment that have intrinsically high combustion temperatures resulting in reduced CO (<50 ppm), unburnt hydrocarbons (UHC) (<25 ppm) and particulate emissions as flue gas.

Selection of electric starters for the three turbines rather than a pneumatic (i.e. fuel gas) alternative.

4 The calculated emission outputs from the gas fuelled Solar Mars 100 gas turbine driven compressors and the Centaur 40 gas turbine driven electrical power generator have been provided by the turbine vendor (Solar Turbines) and are as summarised in Table 8-1.

5 Reference should be made to Section 8.1.5 where the purpose of flue gas monitoring points is explained.


Table 8-1: Calculated Air Emissions from VICPOP Turbine Driven Machines under Routine

Operating Conditions

Source Exit Velocity

(m/s) Temp

(K)

NOX

(g/s)

NOX

(mg/Nm3)

SO2

(g/s)

Rsmog*

(g/s)

Power Generator (3.5 MW) Centaur 40 (Tag No. G9001)

8.8 726 0.84 60 0 0

Compressors (10.5 MW) Mars 100 (Tag Nos. K0302 & K0402)

16.2 772 2.27 70 0 0

(Source: Solar Turbines based on performance runs conducted on 4/06/13 at 11oC ambient)

*Rsmog is a summary measure of volatile organic compounds).

The emission values in Table 8-1 were then used as the basis of air quality modelling as described in Section 8.1.4 for routine, steady state conditions. It should be noted that SO2, UHC, CO and PM10 were not modelled due to their very low levels within the turbine flue gas.

Likewise, Benzene, Toluene, Ethylbenzene and Xylene (BTEX) arising from fugitive emissions within the VICPOP works area was considered to be negligible and therefore not modelled.

Air Quality Assessment Criteria

8.1.3.1 Point Source Emissions

Emission targets for key air emission point sources during normal operation are shown in Table 8-2 below. Design emissions targets are sourced from the New South Wales (NSW) NSW Protection of the Environment Operations (Clean Air) Regulations 2010. The NSW emission targets are used for comparison purposes in absence of numerical stack standards from WA DWER.

Table 8-2: Point Source Emission Targets for during Normal Operation

Pollutant Maximum Concentration

Source mg/Nm3

Oxides of nitrogen (NOX, as NO2) 701,2 NSW Protection of the Environment Operations (Clean Air) Regulations 2010

Carbon monoxide (CO) 125

Volatile organic compounds (VOCs) 40

Sulfur Dioxide (SO2) N/A

1Turbine operating on gas, capacity less than 10 MW. 2 Calculated as NO2 at a 15% oxygen reference level, dry, at standard temperature (0°C) and pressure (1 atmosphere).

Comparison between Table 8-1 and Table 8-2 serves to confirm that the turbine engines consuming fuel gas as required for the VICPOP will achieve NOX (as NO2) emissions of 70 mg/Nm3 for each of the compressor turbines and 60 mg/Nm3 for the generator turbine; values that are equal to or less than the guideline value of 70 mg/Nm3.

8.1.3.2 Ambient Air Quality Criteria

The WA EPA provides guidance for assessing the potential impacts of a proposal on air quality in the Environmental Factor Guideline: Air Quality, published in 2016 (EPA, 2016). However this guideline does not specify air quality standards for assessment.


In the absence of specific air quality standards from the DWER, it is common practice for the NEPM (Ambient Air Quality) to be adopted for air quality impact assessments in WA. The relevant NEPM (Ambient Air Quality) standards shown in Table 8-3.

Table 8-3: NEPM (Ambient Air Quality) Standards relevant to VICPOP

Pollutant Averaging

Period

Maximum Concentration

Goal

ppm (μg/Nm3)1 Maximum Allowable Exceedances

Carbon monoxide (CO) 8-hour 9.0 11240 1 day a year

Nitrogen dioxide (NO2) 1-hour 0.12 246 1 day a year

1-year 0.03 62 None

Photochemical Oxidants (as Ozone)

1-hour 0.10 214 1 day a year

4-hours 0.08 171 1 day a year

Sulphur dioxide (SO2)

1-hour 0.20 572 1 day a year

1-day 0.08 228 None

1-year 0.02 57 None

Particles as PM10 1-day - 50 None

1-year - 25 None

Particles as PM2.5 1 day - 25 -

1-year - 8 -

1Concentration of gaseous pollutants in italics have been converted from the NEPM standard quoted at 0 oC and 101.3 kPa.

*It is noted that the Commonwealth of Australia has published a Notice of Intention to vary the NEPM (Ambient Air Quality). However, as that amendment has not been formalised this air assessment has only considered the 2015 standards, which were in force at the time of writing this air quality impact assessment.

When assessing BTEX as an indicator of VOCs, the National Environment Protection (Air Toxics) Measure 2011 and the New South Wales Environment Protection Authority assessment criteria (NSW EPA, 2016) are two relevant options.

The NEPM (Air Toxics) contains Monitoring Investigation Levels (MILs) that are used in the assessment of ambient hydrocarbon concentrations. The MILs that are relevant to VICPOP are shown in


Table 8-4. The NEPM (Air Toxics) sets out standards for long term (annual) averages because these are more readily related to human health effects than shorter term averages.

The New South Wales (NSW) Environment Protection Authority assessment criteria (NSW EPA, 2016) are relevant as they set out hourly average concentration assessment criteria. Therefore, the NSW EPA assessment criteria can be used to assist with interpretation of measured hourly average concentrations.


Table 8-4: NEPM Air Toxic Monitoring Investigation Levels and NSW EPA Assessment Criteria

Pollutant Averaging Period NEPM MIL NSW EPA (2016)

ppm (μg/Nm 3)2 ppm (μg/Nm 3)2

Benzene1 1-hour - - 0.009 29

Annual - average* 0.003 9.6 - -

Toluene1

1-hour - - 0.09 360

24-hours 1.0 3770 - -

Annual - average* 0.1 377 - -

Xylenes1

1-hour - - 0.04 190

24-hours 0.25 1085 - -

Annual - average* 0.2 868 - -

1 Benzene, Toluene and Xylene as BTEX components. 2 Equivalent concentration at 101 kPa and 25oC. 3 annual average concentration as the arithmetic mean concentration of 24-hour monitoring results.

*Note: The 8-year goal of the air toxics NEPM is to gather sufficient data nationally to facilitate the development of a standard.

Emissions Modelling

In the absence of specific air quality standards from the DWER, it is common practice for the NEPM (Ambient Air Quality) to be adopted for air quality impact assessments in WA. Therefore, to assess potential ground level concentrations (GLC) for the VICPOP, modelled predictions were assessed against the relevant NEPM (Ambient Air Quality) standards shown in Table 8-3.

Modelling for the existing VI emission sources and additional source emissions arising from the VICPOP’s turbine powered compressors and electrical generator were conducted following

submission of a Briefing Note (PE, 2012) to the DWER’s Air Quality Monitoring Branch and the subsequent advice from the DWER (refer to Section 2.2 of the Air Quality Assessment; Appendix 6).

The maximum predicted ground level concentrations for NOX (as NO2) for all existing sources on VI (including components of the VICPOP) are summarised in Table 8-5.

Data presented in the table resulted from the emissions modelling as part of the VICPOP Air Quality Assessment (Doc. Ref: JB-10-RI-014), undertaken on behalf of Santos WA by Pacific Environment Limited (PE), a copy of which has been included as Appendix 6. Although this modelling was undertaken in 2013, the plant configuration, emission sources and the NEPM criteria for NOX (Table 8-5) remains unchanged. Therefore the modelling of GLC of NOX is valid for VICPOP and this WAA.

Table 8-5: Predicted Air Emissions from VI under Routine Operating Conditions (Source: PE

(2013))

Averaging Period

Scenario Predicted Maximum Concentration NOX

1

(μg/Nm3)

NEPM Criteria NOX

1 (μg/Nm3)

Percentage of NEPM

Criteria (%)

1-hour Existing 213 246 86.6%

Existing Including VICPOP 214 246 87.0%

1-year Existing 75.3 62 121.5%

Existing Including VICPOP 75.7 62 122.1% 1NOX as NO2


From Table 8-5 it is apparent that:

The introduction of additional emissions due to the VICPOP turbines will result in an increase of 1 μg/Nm3 (equivalent to 0.4%) in the maximum predicted 1-hour NOX ground level concentration on VI (PE, 2013).

The maximum predicted 1-hour ground level concentrations of NOX for both the existing emissions and for emissions including the VICPOP are significantly (13%) lower than the NEPM NOX criteria (PE, 2013).

The ground level concentration of NOX attributable to the introduction of the additional emission sources associated with the VICPOP, is predicted to result in an insignificant increase of 0.4 μg/Nm3 (equivalent to 0.6%) in the annual average on VI (PE, 2013).

It should be noted that the 1-hour ground level concentrations are very conservative for reasons described below.

For the annual predicted ground level concentrations for NOX, the model prediction is that the maximum will be above the NEPM criteria of 62 μg/Nm3. However it should be noted that this is entirely due to the very conservative emission rates used in the model based upon the following:

The existing power generators (EG-6001 and EG-6002), will after completion of the VICPOP have a utilisation factor of 4% (approx.) but were modelled at 100% utilisation.

The existing black start power generators (EG-1 and EG-2) have a utilisation factor of 2% (approx.) but were modelled at 100% utilisation.

The existing sales gas compressor (K-6401-C) has a utilisation factor of 12% (approx.) but was modelled at 100% utilisation.

The existing gas lift compressors (K-11A and K-11B) have a utilisation factor of 50% (approx.) but were modelled at 100% utilisation.

The shipping pumps (G-101A, G-101B and G-101C) have a utilisation factor of 2% (approx.) but were modelled at 100% utilisation.

The fire water pumps (P-910A and P-910B) have a utilisation factor of 2% (approx.) but were modelled at 100% utilisation.

This very conservative modelling method results in annual emissions significantly in excess of actual annual emissions. This in turn results in predicted ground level concentrations significantly higher than what would actually occur. The key aspect of the annual ground level concentrations is that the introduction of additional VICPOP emission sources is predicted to result in an insignificant increase, of approximately 0.4 μg/Nm3, in the annual average (PE, 2013).

Stack Emission Monitoring

Santos WA intends to undertake a program of turbine flue gas sampling and analysis of the turbine equipment that is the subject of this WAA. The sampling program will be conducted during the VICPOP commissioning period (not exceeding 90 days).

The flue gas sampling and analysis regime will rely on and include the following:

Use of pre-fitted flue gas sampling points specified by Santos WA on the flue gas exhaust stacks for both the compressor turbines and the generator turbine and as installed (i.e. required sampling points) during turbine package fabrication by Solar Turbines.

Engagement by Santos WA of an independent and accredited third party to develop the sampling regime, undertake the turbine flue gas sampling on site, manage the sample analysis at a National Association of Testing Authorities approved laboratory and to prepare the required stack emission monitoring report for Santos WA.

Sampling is to be undertaken so as to be representative of the compressor turbines and the generator turbine normal operating conditions.

Sampling to include NO2, CO, SO2, BTEX and particulates (PM10).

Sample results are to be compared to the relevant emission criteria as presented in Table 8-2.


Summary

The emission control and assessment measures that have been implemented for the management of the atmospheric emissions (i.e. routine, non-routine and fugitive) originating from within the VICPOP works area indicate that combustion emissions will be reduced to ALARP. This conclusion is supported by the following:

The turbine combustion emission control measures as outlined in Section 8.1.2.

The predicted maximum 1-hour NOX concentrations as modelled and summarised in Section 8.1.4 and shown to be below the NEPM criteria.

The relatively insignificant routine emissions from compressor dry gas seals as described in Section 8.1.1.2.

The proportionately low level of non-routine emissions (i.e. gas flaring) due to the relatively small containment volumes within the VICPOP process pipework as described in Section 8.1.1.3.

The minor to insignificant level of fugitive emissions as described in Section 8.1.1.4

Therefore, in accordance with the Santos WA risk matrix, the risks associated with atmospheric emissions (combustion) are considered to be low and acceptable.

8.2 Atmospheric Emissions (Dust)


Vehicle traffic within the VICPOP works area during operations has the potential to create atmospheric dust.

Management Controls

Measures to control dust emissions during operations include the following:

The VICPOP works area will be paved in all areas requiring mobile equipment access.

During operations, mobile equipment access will be limited to that required for scheduled and routine maintenance only.

Vehicles, other than mobile equipment, will not be allowed to enter the VICPOP area as is the current access limitation within the ESJV gas plant area.

Risk Assessment

The measures to be implemented for the control of air borne dust during VICPOP operations will ensure that there will be no significant increase in dust levels. Therefore, in accordance with the Santos WA risk matrix, the risks associated with atmospheric emissions (dust) were assessed as being low and acceptable.

8.3 Noise and Vibration Emissions


Operations within the VICPOP will increase ambient noise and vibration levels.

Management Controls

Measures to control noise and vibration during operations include the following:

Selection of rotating engines (i.e. turbine powered) which have inherently low vibration levels rather than reciprocating machines.

Selection of fully enclosed turbine engines with integral noise attenuating lagging fitted throughout each enclosure.


Risk Assessment

The additional noise emissions due to VICPOP operations will represent a marginal increase to the existing ambient levels and therefore, in accordance with the Santos WA risk matrix, noise risks during operations are considered to be low and acceptable.

Vibration emissions due to VICPOP operations are considered to be insignificant and therefore, in accordance with the Santos WA risk matrix, vibration risks during operations are considered to be low.

8.4 Light Emissions


VICPOP operations that rely on the use of fixed lighting within process areas, as required for personnel safety at night, may present light spill to sensitive environmental receptors (e.g. marine turtle nesting beaches).

Management Controls

A number of measures to control light emissions during operations will be implemented including the following:

Lighting required for operations and maintenance will comply with the requirements of Santos WA’s

Lighting Management Plan (Doc. Ref: EA-60-RI-153).

Lighting within the VICPOP works area will comply with the Process Facility Outdoor Illumination Plan (Doc. Ref: JB-10-RE-044).

Lighting within the VICPOP operational areas will be switched off unless lights are required for routine inspections (the areas will normally be unoccupied at night).

The electrical switch room has been designed without windows.

Manual light switches will be located throughout the operational areas enabling operators to turn lights on/off.

Lighting within the operational areas will be monitored and controlled via the existing constantly manned central control room (i.e. the VI Control Building).

Filters (typically amber) will be fitted to all fluorescent tubes to minimise energy transmitted in wavelengths below 560 nm (light in the 450 to 500 nm range is most visible to turtles).

Diffusers and shields will be fitted to all lights in elevated locations to prevent direct light (i.e. light fixture filament) visibility from turtle nesting beaches.

Lights will be installed horizontally to the floor to contain the light within the confines of plant within the operational areas.

Lighting for the VICPOP operational areas has been modelled to project and illustrate the extent of direct light and the potential for light spill to sensitive environmental receptors.

Any lighting that has the potential to be visible from breeding marine turtles will be ALARP (as verified by turtle experts), and combined with on-going light surveys and marine turtle population monitoring.

Risk Assessment

Lighting impacts and the proposed light spill mitigation measures to be implemented during VICPOP operations have been considered by the EPA, the DMIRS and DOTEE as summarised in Table 5-1.

Santos WA has a commitment to on-going programs light spill monitoring and turtle biology monitoring designed to ensure that there are no long term significant impacts to marine turtles.

Light emissions arising from VICPOP operations will be ALARP and therefore, in accordance with the Santos WA risk matrix the risks associated with light spill during operations that may affect sensitive environmental receptors (i.e. turtle nesting beaches) were assessed as being medium and acceptable.


8.5 Discharges to Water


During VICPOP operations, oil-contaminated water arising from storm events and equipment wash-down is typically produced as run-off from bunded areas, drains and equipment skid pans. Run-off is typically contaminated with oils and greases, effluents, detergents and surfactants. Non-routine events, such as shutdowns and unplanned maintenance, can also result in the generation of increased levels of contaminated wash-down water.

Run-off resulting from paved trafficable surfaces (e.g. paths and roadways) resulting from storm events has the potential to present residual oil and sediment into drainage lines and ultimately into near-shore waters.

Management Controls

A number of measures to limit and prevent discharges to water during VICPOP operations will be implemented including the following:

The module sumps are to be of monolithic construction with no joints between the floor and walls. The concrete specified is a silica fume mix that has improved strength, increased resistance to hydrocarbons and reduced permeability over conventional high strength Portland cement mixes.

The turbines will be fitted with an on-line demineralised water wash capability so that washing products (water and dust particulates) will pass through the combustion process and be discharged as vapour.

The proposed VICPOP equipment modules and the electrical transformer compound will incorporate integral collection pans and containment sumps that will provide for the containment of wash-down products and also provide secondary containment for chemicals and hazardous materials (e.g. turbine lubricating oil and transformer cooling oil) within the installed plant.

The containment sumps will be routinely pumped out by the gas plant utility operators using a Wilden pump or similar as is current practice.

The module pan and sump arrangements are to be connected to a closed drain system that will discharge into a downstream Humeceptor oily water separator. The oil retained and separated by the Humeceptor will be routinely pumped out by the gas plant utility operators using a Wilden pump or similar as is current practice. The liquid Humeceptor and containment sump waste products are then treated via the existing corrugated plate interceptor (CPI) plant that reduces entrained hydrocarbons to a level of approximately 30 ppm, after which the separated hydrocarbon liquid is recycled into the condensate stabilisation process and treated water pumped to the PFW treatment system for eventual disposal into depleted petroleum reservoirs.

The VICPOP operational area’s roads and paved access paths will incorporate a storm water

drainage system separate and distinct from the closed drain system described above. Collected storm water will discharge into a separate downstream Humeceptor oily water separator. The oil retained and separated by the Humeceptor is routinely pumped out by the gas plant utility operators and be treated as described above.

The storm water drainage scheme will be adequately sized based upon the 20 year average return interval (ARI) event of 140 mm of rainfall over a 24 hour period.

Both the closed drain Humeceptor and the storm-water drain Humeceptor will discharge to an existing HDPE lined sediment retention / evaporation pond. If sufficient VICPOP water run-off quantities are generated by a storm event, discharge will occur from the pond into the existing drainage lines on the lease land adjacent to the ESJV gas plant. The retention pond is sized to allow settlement of and to prevent carry over sediment prior to discharge into existing drainage lines within the Santos WA lease area.

An extensive network of groundwater monitoring bores exists across the VI, including process areas. Groundwater sampling and laboratory analysis will be undertaken in accordance with the VI Hub Operations Environment Plan (Doc. Ref: EA-60-RI-186) which includes reference to


procedures for groundwater sampling and testing as is applicable to the existing array of monitoring sites within the Santos WA lease area.

Risk Assessment

Any carry-over of residual hydrocarbons or sediment from the drainage schemes that service the VICPOP operations area will be insignificant and together with the existing robust groundwater monitoring regime, the operational residual risks associated with discharges to water that may affect sensitive environmental receptors were assessed as being low and acceptable.

8.6 Discharges to Ground


VICPOP operations may from time to time require localised coating applications on steel and pipework for the purposes of maintenance and this may result in localised coating overspray to ground.

Faulty maintenance on equipment has the potential to create leaks resulting in a discharge to ground.

There is the potential for compressor lubricating oil spills, transformer oil spills or other equipment spills to discharge to ground.

Management Controls

A number of measures to limit and prevent discharges to land during VICPOP operations will be implemented including the following:

Maintenance of mobile equipment (e.g. cranes) to ensure hydraulic lines and engine sumps are competent and without evidence of leaks.

Provision of spill kits within the VICPOP operations area to facilitate immediate clean-up.

Machinery servicing (oil change and lubrication) to be conducted only within designated areas outside the VICPOP operations area.

The use of rotary devices for metal preparation rather than grit blasting (as a potential source of ground contamination) for the purposes of substrate preparation prior to coating applications.

The use of screens and ground sheets to prevent paint spray contamination of the ground surface.

Risk Assessment

Discharges to ground arising from VICPOP operations will be insignificant and therefore, in accordance with the Santos WA risk matrix, the risks associated with these discharges were assessed as being low and acceptable.

8.7 Solid Non-hazardous Wastes

Waste Description

VICPOP operations will produce quantities of scrap piping and metal, packaging and pallets arising from maintenance work. Domestic and putrescible waste will also be generated from the operational workforce accommodated on VI.

Management Controls

The measures to manage solid non-hazardous waste resulting from VICPOP operations are the same as those presented in Section 7.6.2.

Risk Assessment

On the basis that existing solid waste management processes on VI are effective the risk of non-compliant storage and handling of solid waste originating from VICPOP operations is considered to be


insignificant and therefore, in accordance with the Santos WA risk matrix, the risks associated with solid waste management were assessed as being low and acceptable.

8.8 Liquid Non-hazardous Wastes

Waste Description

Sewage and greywater will be produced throughout VICPOP operations however it should be noted that the VICPOP will not require any change to the existing accommodation capacity on VI.

Management Controls

The measures to manage liquid wastes (sewerage and greywater) resulting from VICPOP operations are the same as those presented in Section 7.7.2.

Risk Assessment

On the basis of the proposed mitigation measures the risks associated with liquid waste management arising from VICPOP operations were assessed as being low and acceptable.

8.9 Hazardous Wastes

Waste Description

Hazardous waste will be generated from VICPOP operations. Typical hazardous wastes will include solvents, waste paints and the lubricating oils and oil filters as required for the turbines.

Management Controls

The measures to manage hazardous wastes resulting from VICPOP operations are the same as those presented in Section 7.8.2.

Risk Assessment

The control measures to be implemented for the management of hazardous wastes associated with VICPOP operations indicate that the risks are ALARP condition for storage and handling will be achieved and therefore, in accordance with the Santos WA risk matrix, the risks associated with hazardous waste management were assessed as being medium and acceptable.

9 Environmental Management

Santos WA manages all operations in accordance with the Santos WA Environmental Management Policy (Refer to Appendix 5) and will fulfil its commitments and the management measures required as a result of the applications made (Refer to Section 2.2) and the associated commitments detailed in the VICPOP Commitments Register (Doc. Ref: JB-10-HI-001) for the construction phase of the VICPOP. These include regulatory requirements, company standards and project commitments, including any VICPOP specific environmental approval conditions.

The VICPOP will undertake construction and operations in compliance with the existing VI Hub Operations Environment Plan (Doc. Ref: EA-60-RI-186) that was revised in September 2014. In addition Santos WA has prepared a CEMP bridging to the current approved VI Hub Operations EP (Doc. Ref: WA-60-RI-186) that will be submitted to DMIRS for approval prior to the commencement of construction.

An integral part of the implementation of the VICPOP is the provision of environmental awareness information to all personnel involved in the works. As a minimum, the environmental induction package will ensure workers are made aware of the environmental sensitivities of VI and the VICPOP


environmental management requirements. Induction materials will be tailored to be appropriate for a number of different groups of workers.

The Santos WA assurance schedule will include audits against the VICPOP Commitments Register to verify compliance.

In respect of matters that are the subject of the WAA, Santos WA will produce an environmental compliance document which will be submitted to the DWER following completion of the works. The compliance document will provide verification that the works have been completed in accordance with the conditions of the Works Approval.

10 Works Approval Fee

The works approval fee calculation is based on:

Assumed cost of works = $270 million

Fee Units for a facility that is more than $100,000,000 = 1405 units

Works Approval Fee = 1405 units x $40.60 per unit (on or from 1 July 2018) = $57,043

11 Conclusion

Santos WA has undertaken a comprehensive risk assessment of the emissions, discharges and wastes arising from the VICPOP construction and operations phases.

On the basis that the identified management controls will be implemented, it has been concluded that the ALARP requirement in respect of residual risks has been met and that there should be no impediment to the granting of a Works Approval for the VICPOP works as presented herein. It should also be noted that a Works Approval was previously granted for VICPOP and that the works have been substantially progressed. No significant changes to the project have been made since 2014.

The conclusions resulting from the atmospheric emissions modelling described within the VICPOP Air Quality Assessment (PE, 2013) as conducted on behalf of Santos WA may be summarised as follows:

The introduction of additional emissions due to the VICPOP turbines will result in an increase of 1 μg/Nm3 (equivalent to 0.4%) in the maximum predicted 1-hour NOX ground level concentration on VI (PE, 2013).

The maximum predicted 1-hour ground level concentrations of NOX for both the existing emissions and for emissions including the VICPOP are significantly (13%) lower than the NEPM NOX criteria (PE, 2013).

The ground level concentration of NOX attributable to the introduction of the additional emission sources associated with the VICPOP, is predicted to result in an insignificant increase of 0.4 μg/Nm3 (equivalent to 0.6%) in the annual average on VI (PE, 2013).

Based upon the predicted NOX values, Santos WA is of the view that the supporting documentation (this document), together with the implementation of the proposed turbine flue gas monitoring regime are sufficient for the grant of Works Approval for the intended VICPOP works.


12 References

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Astron Environmental Services December 2011. Varanus and Bridled Island Annual Vegetation Monitoring Report, Prepared for Apache Energy Limited. Perth, WA.

Astron Environmental Services December 2019. Quadrant Environmental Monitoring Program Varanus and Airlie Islands Seabird Monitoring Annual Report 2019, Prepared for Santos WA Energy Ltd. Perth, WA.

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Brooke, M. De L. 2004. Albatrosses and petrels across the world. Oxford University Press, Oxford.

Department of Environment and Conservation, 2007, Management Plan for the Montebello/Barrow Islands Marine Conservation Reserves 2007-2011 – Management Plan No. 55

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Department of Sustainability, Environment, Water, Population and Communities (SEWPaC), 2012c. Species Group Report Card – Marine Reptiles. Available from: http://www.environment.gov.au/coasts/marineplans/north-west/pubs/north-west-marine-plan.pdf

Department of Sustainability, Environment, Water, Population and Communities (SEWPaC), 2012e. Green turtle (Chelonia mydas). Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available from: http://www.environment.gov.au/coasts/species/turtles/green.html

Department of Sustainability, Environment, Water, Population and Communities (SEWPaC), 2012f. Onychoprion anaethetus— Bridled Tern. Department of Sustainability, Environment, Water, Population and Communities, Canberra, ACT. Available from: http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=814

Dethmers, K.M., D. Broderick, C. Moritz, N. Fitzsimmons, C. Limpus, S. Lavery, S. Whiting, M. Guinea, R.I.T. Prince and Kennett, R. 2006. The genetic structure of Australasian Green Turtles (Chelonia mydas): exploring the geographical scale of genetic exchange. Molecular Ecology. 15:3931-3946.

Environmental Protection Authority (EPA), 2010. Environmental Assessment Guideline for Protecting Marine Turtles from Light Impacts. No 5. May 2010.

Halfmoon Biosciences 2012. Seabird Impact Assessment for VI Works, Report Prepared for Apache Energy Limited. Perth, WA.

Kolluru, R. V. 1994. Environmental Strategies Handbook – A Guide to Effective Policies and Practices. McGraw-Hill.

LeProvost Semenuik and Chalmer. 1988. Harriet Field Development Triennial Environmental Report. Unpublished Report to Bond Corporation Pty Ltd, October 1988.

Limpus, C.J., 2002 - Western Australian Marine Turtle Review. A study commissioned by Western Australian Department of Conservation and Land Management, October 2002.

London. WNI 1995. Preliminary report on ambient and non-cyclonic design criteria for the Stag location. WNI Science & Engineering. December 1995.

Marchant, S & Higgins, PJ (eds) 1990. Handbook of Australian, New Zealand and Antarctic birds, volume 1: ratites to ducks, part A: ratites to petrels, Oxford University Press, Melbourne.

http://www.environment.gov.au/coasts/marineplans/north-west/pubs/north-west-marine-plan.pdf



http://www.environment.gov.au/coasts/species/turtles/green.html

http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=814

http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=814


NSW EPA 2016. Approved Methods for the Modelling and Assessment of Air Pollutants in New South Wales. NSW Environmental Protection Authority. Sydney, NSW.

Nicholson, L.W. 2002. Breeding strategies and community structure in an assemblage of tropical seabirds on the Lowendal Islands, Western Australia. Unpublished PhD Thesis, Murdoch University, Perth Western Australia.

Pacific Environment Limited, 2012. VICP – Dispersion Modelling. Briefing Note prepared for Apache Energy Limited. Perth, WA.

Pacific Environment Limited, 2013. Varanus Island Compressor Project – Air Quality Assessment (JB-10-RI-014). Report prepared for Apache Energy Limited. Perth, WA.

Parsons Brinckerhoff, (2005) Groundwater monitoring event. Apache Energy lease area. Varanus Island. WA. Draft Report. Prepared by Parsons Brinckerhoff Australia Pty Ltd, Subiaco, for Apache Energy Limited. Perth, WA.

Parsons Brinckerhoff, 2012. Investigations of Soils Associated with the Main Bund on Varanus Island WA, Report Prepared for Apache Energy Limited. Perth, WA.

Pendoley, K.L. 2005. Sea Turtles and the Environmental Management of Industrial Activities in North West Western Australia, PhD Thesis, Murdoch University, Australia. 310pp.

Pendoley Environmental 2011. Varanus Island Marine Turtle Monitoring Program. Report prepared for Apache Energy Limited. Perth, WA.

Pendoley Environmental 2012. Varanus Island Facility Upgrade Desktop Assessment of Potential Impacts to Marine Turtles. Report prepared for Apache Energy Limited. Perth, WA.

Pendoley Environmental 2013. Varanus Island Marine Turtle Monitoring Program 2013/13 Season. Report prepared for Apache Energy Limited. Perth, WA.

Pendoley Environmental 2019. Varanus and Airlie Island Shearwater Monitoring Annual Report 2018/19. Report prepared for Santos Limited. Perth, WA.

Pendoley Environmental 2019. Varanus Island Turtle Monitoring: Annual Report 2018/19. Report prepared for Santos Limited. Perth, WA.

Phoenix Environmental Sciences 2012a. Short-Range Endemic Invertebrate Fauna Survey and Subterranean Fauna Desktop Review of the Varanus Island Fill Project. Report Prepared for Apache Energy Limited. Perth, WA.

Phoenix Environmental Sciences 2012b. Vertebrate Fauna Survey for Varanus Island Fill Project. Report Prepared for Apache Energy Limited. Perth, WA.

Prince R.I.T. 1994. Status of the Western Australian Marine Turtle Populations: The Western Australian Marine Turtle Project 1986–1990. Report prepared for the Queensland Department of Environment and Heritage and Australian Nature Conservation Agency.

Semeniuk Aug 1992. Monitoring of Terreatrial Vegetation, Lowendal Island Group, Harriet Oil Field Development – Results of Survey, V&C Semeniuk Research Group.

Sinclair Knight Mertz 2008. Apache Varanus Island Mars Gas Turbine Upgrade. Report Prepared for Apache Energy Limited. Perth, WA.

SSE 1991. Normal and extreme environmental design criteria. Campbell and Sinbad locations, and Varanus Island to Mainland Pipeline. Volume 1. Prepared for Hadson Energy Limited by Steedman Science and Engineering. Report E486. March 1991.

SSE 1993. Review of oceanography of North West Shelf and Timor Sea regions pertaining to the environmental impact of the offshore oil and gas industry. Vol I prepared for Woodside Offshore Petroleum and the APPEA Review Project of Environmental Consequences of Development Related to the Petroleum Production in the Marine Environment: Review of Scientific Research, Report E1379, October 1993.


Whiting, S.D., Guinea, M.L. and Pike, G.D. 2000. Sea turtle nesting in the Australian Territory of Ashmore and Cartier Islands, Eastern Indian Ocean. In: Sea Turtles of the Indo-Pacific-Research Management and Conservation. (ed N. Pilcher and G. Ismail). ASEAN Academic Press LTD, London.

Woodside, 2006 - Pluto LNG Development - Draft Public Environment Report / Public Environmental Review EPBC Referral 2006/2968 Assessment No. 1632 December 2006.


Appendix 1 – Varanus Island Emission Points to Air


Existing Varanus Island Emission Points to Air

Emission Discharge Point Emission

Point Height (m)

Discharge Point Location as shown in Varanus Island Emission Points to Air

NOX, PM, Acrolein

HJV Centaur Compressor (CM-11.301) 13 Discharge point A1

HJV Centaur Compressor (CM-11.301) 13 Discharge point A2

NOX, PM

ES Power Generator (EG-6001) 5 Discharge point A3



NOX, PM, Acrolein

Centaur Driven Produced Water Pump (G-306) Gas Turbine

7.5 Discharge point A6

Taurus 60 (K-11A) Gas Turbine 11 Discharge point A7

Taurus 60 (K-11B) Gas Turbine 11 Discharge point A8

Taurus T70 (K-12) Gas Turbine 12 Discharge point A9

NOX

ESJV - Taurus A (K-6401-A) Gas Turbine 13 Discharge point A10

ESJV - Taurus B (K-6401-B) Gas Turbine 13 Discharge point A11

ESJV - Taurus C (K-6401-C) Gas Turbine 13 Discharge point A12

Mars 100 ESJV Sales Gas Compressor (K-6401-D)

20 Discharge point A13

NOX, PM, Acrolein

Saturn Generator (PGI-9) 9 Discharge point A14

Saturn Generator (PGI-10) 9 Discharge point A15

NOX, PM Black start Diesel Generator (EG-1) 6 Discharge point A16

Black start Diesel Generator (EG-2) 6 Discharge point A17

NOX, PM, CO, Benzene, n-hexane

HJV Elevated Flare (F-101) 35 Discharge point A18

HJV Ground Flare (F-100) 15 Discharge point A19

ESJV Elevated Flare (V- 6542) 33 Discharge point A20

ESJV Ground Flare (V-6541) 8 Discharge point A21

H2S Amine Train Vent 1 (AV1) 24 Discharge point A22

Amine Train Vent 2 (AV2) 24 Discharge point A23

Proposed VICPOP Emission Points to Air

Emission Discharge Point Emission

Point Height (m)

Discharge Point Location as shown in Varanus Island Emission Points to Air

NOX

Mars 100 ESJV Inlet Gas Compressor (K-0302)


Mars 100 ESJV Inlet Gas Compressor (K-0402)


Centaur C40 (G-9001) Gas Turbine Generator



Appendix 2 – VICPOP Process Flow Diagrams


Appendix 3 – Solar Turbines Data Sheets


Appendix 4 – Santos WA Risk Matrix

Category Description and Response

High Risk Reduction of risk required

Medium Risk Reduction of risk required based on ALARP principal

Low Risk Deemed acceptable based on standard risk controls in place


Appendix 5 – Santos Environmental Policy


Appendix 6 – VICP Air Quality Assessment (PE Report - 2013)

REPORT

VARANUS ISLAND COMPRESSION PROJECT

(VICP) – AIR QUALITY ASSESSMENT (DOC REF:

JB-10-RI-014) – REV 0

Apache Northwest Pty Ltd

Job No: 7042

20 August 2013

www.pacific-environment.com

http://www.pacific/

JB-10-RI-014 Varanus Island Compressor Project - Air Quality Assessment Rev0 ii

Apache Northwest Pty Ltd | Job Number 7402

PROJECT TITLE: Varanus Island Compression Project (VICP) – Air

Quality Assessment (Doc Ref: JB-10-RI-014) – Rev 0

JOB NUMBER:

7042

PREPARED FOR:

Apache Northwest Pty Ltd

APPROVED FOR RELEASE BY:

Jon Harper

DISCLAIMER & COPYRIGHT:

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located at www.pacific-environment.com © Pacific

Environment Operations Pty Ltd ABN 86 127 101 642

DOCUMENT CONTROL

VERSION DATE PREPARED BY REVIEWED BY

1 28/6/2013 Sean Lam, Peter D‘Abreton Jon Harper

2 26/7/2013 D Tuxford Jon Harper

3 20/8/2013 Jon Harper Jon Harper

Pacific Environment Operations Pty ABN 86 127 101 642

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JB-10-RI-014 Varanus Island Compressor Project - Air Quality Assessment Rev0 iii


DISCLAIMER

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JB-10-RI-014 Varanus Island Compressor Project - Air Quality Assessment Rev0 iv


CONTENTS

1 EXECUTIVE SUMMARY 1

2 INTRODUCTION 3 2.1 Background 3 2.2 Scope of Work 3

3 CLIMATE 4

4 AIR QUALITY GUIDELINES 8

5 EMISSIONS ESTIMATION 9 5.1 Emission Sources 9 5.2 Emission Parameters 10

5.2.1 Existing scenario 10 5.2.2 Future scenario 11 5.2.3 Cumulative scenario 12

5.3 Modelling Methodology 13 5.3.1 TAPM 13 5.3.2 Merging Multiple Stacks 14 5.3.3 Modelling Flares 15 5.3.4 NOX to NO2 Conversion 16

6 METEOROLOGICAL MODELLING 18 6.1 Wind 18 6.2 Atmospheric Stability 18 6.3 Mixing Height 20 6.4 Model Validation 21 6.5 Statistical Measures of Model Performance 24

6.5.1 Geometric Mean 24 6.5.2 Geometric Variance 24 6.5.3 Skill_r 24 6.5.4 Skill_v 25 6.5.5 Model Bias 25 6.5.6 Fraction Bias 25 6.5.1 Root Mean Square Error (RMSE) 26 6.5.2 Index of Agreement 26

7 MODEL RESULTS 28 7.1 Varanus Island 28

7.1.1 Existing 29 7.1.2 Expansion 30

7.2 Cumulative 32 7.2.1 Existing 32 7.2.2 Expansion 34

8 CONCLUSION 37

9 REFERENCES 39

TABLES

Table 4-1: NEPM Air quality goals relevant to this study 8

Table 5-1: Source characteristics - Existing 9

Table 5-2: Source characteristics – Future (additional to Existing scenario) 10

Table 5-3: Emission characteristics – Existing scenario 11

Table 5-4: Emission characteristics – Future scenario (additional to existing scenario) 12

JB-10-RI-014 Varanus Island Compressor Project - Air Quality Assessment Rev0 v


Table 5-5: Emission characteristics – Cumulative scenario (additional to existing and future scenario) 12

Table 5-6: TAPM Specifications for 2010 Simulations 14

Table 5-7: Buoyancy enhancement factor 15

Table 5-8: Flare parameters for modelling (source: Apache Northwest Pty Ltd) 16

Table 6-1: Mesoscale model benchmarks (after Emery et al, 2001; Teschke et al, 2001) 27

Table 6-2: Results of statistical test: Summer 27

Table 7-1: Maximum predicted ground level concentrations of NO2 on modelled grid for Varanus Island

28

Table 7-2: Maximum predicted ground level concentrations on modelled grid for the cumulative

scenario 32

FIGURES

Figure 3-1: Monthly rainfall for Barrow Island -1967 to 2000 (source: Bureau of Meteorology) 4

Figure 3-2: Monthly temperature for Barrow Island - 1967 to 2000 (source: Bureau of Meteorology) 5

Figure 3-3: Monthly relative humidity for Barrow Island - 1967 to 2000 (source: Bureau of Meteorology) 5

Figure 3-4: Climate wind roses for Barrow island for 9 am (upper) and 3 pm (lower) – 1999 to 2013

(source: Bureau of Meteorology). 7

Figure 6-1: Annual (top left), 9am (top right) and 3 pm (bottom) wind roses at Varanus Island for 2010 19

Figure 6-2: Frequency distribution of Pasquill-Gifford stability class at Varanus Island for 2010 20

Figure 6-3: TAPM derived hourly mixing height statistics for Varanus Island for 2010 21

Figure 6-4: Scatter plot of hourly modelled versus measured u-component of wind 22

Figure 6-5: Scatter plot of hourly modelled versus measured v-component of wind 22

Figure 6-6 Scatter plot of hourly modelled versus measured temperature 23

Figure 6-7 Frequency plot of hourly modelled versus measured temperature 23

Figure 7-1 Maximum predicted 1-hour NO2 ground level concentrations for the existing scenario

(Varanus Island) (µg/m3) 29

Figure 7-2 Predicted annual averaged NO2 ground level concentrations for the existing scenario


Figure 7-3 Maximum predicted 1-hour NO2 ground level concentrations for the expansion scenario


Figure 7-4 Predicted annual averaged NO2 ground level concentrations for the expansion scenario



(cumulative) (µg/m3) 33

Figure 7-6 Predicted annual average NO2 ground level concentrations for the existing scenario






JB-10-RI-014 Varanus Island Compressor Project - Air Quality Assessment Rev0 1


1 EXECUTIVE SUMMARY

Apache Energy Limited (Apache) owns and operates a gas processing facility on Varanus Island

located off the Pilbara Coast in Western Australia (WA). This facility provides between 35 and 40% of

WA‘s domestic gas supply. To ensure that production rates are not unduly influenced Apache is

seeking to install two additional inlet gas compressors and an additional power generator at this

facility.

Pacific Environment Limited (PEL) has been engaged by Apache to determine the potential impact

of the use of the two additional turbine powered compressors and an additional power generator to

support the Varanus Island Compression Project (VICP). This potential impact to be determined is

based on the changes to air emissions and the relative significance of the change in emissions.

Discussions with the AQMB determined that regional photochemical smog modelling is not

necessary as localised atmospheric modelling should be adequate to demonstrate the potential

impact of the very minor increase in NO2 resulting from the project. It is also agreed that the increase

in SO2 emissions is insignificant due to the low sulfur content of the fuel gas and that any increase in

VOC‘s is also insignificant due to the high exit temperature of the turbines.

For the purpose of this assessment only normal operations have been modelled and not upset

conditions such as emergency shutdown as this is an existing facility that is not increasing capacity.

Emissions from upset conditions will not change beyond that previously modelled as there is no

increase in production capability.

Previous atmospheric modelling for operational changes at Varanus Island have used the Victorian

EPA Gaussian plume model AUSPLUME and have concentrated solely on changes to ground level

concentrations of pollutants on the island itself. As the WA DEC had previously noted concerns

about the applicability of this model the CSIRO model TAPM (version 4) was used which is consistent

with other atmospheric studies in the region.

A review by Apache also determined that the emission sources modelled in the previous 2008

assessment were out of date and were subsequently updated. Using this data four scenarios were

modelled to assess potential impacts from the proposed development namely:

Existing scenario: Current emissions from the Apache operations on Varanus Island;

Future scenario: Current emissions together with the equipment from VICP;

Cumulative existing scenario: Current emissions from the Apache operation on Varanus

Island together with existing and proposed emissions on Barrow Island; and

Cumulative future scenario: The future Apache operations on Varanus Island (post-VICP)

together with existing and proposed emissions on Barrow Island.

The results of the modelling for the Varanus Island operations as a standalone facility determined

that the introduction of the additional emissions associated with VICP would only result in an

increase of 1µg/m3 in the maximum predicted 1-hour ground level concentrations.

For the annual average the model predicted that the maximum will be above the NEPM criteria of

62µg/m3. This is primarily due to the very conservative emission rates used in the model whereby all

sources are assumed to be operating all the time. This is an incorrect assumption as sources, such as

those outlined below, will be operating at much lower frequencies:

The ESJV reciprocating gas engines have a pre-VICP utilisation of 90% and a post-VICP of 4%

though they have been modelled for both scenarios (pre and post) with a utilisation of 100%;

The black start diesel generators have a pre-VICP utilisation of 2% and a post-VICP of 2% and they

have been modelled for both scenarios (pre and post) with a utilisation of 100%;



One of the Taurus Gas Turbines has a pre and post VICP utilisation of 12% and has been modelled

for both scenarios (pre and post) with a utilisation of 100%;

The Taurus T60 gas turbines have a pre and post VICP utilisation of 50% and have been modelled

for both scenarios (pre and post) with a utilisation of 100%;

The three shipping pumps, which have a pre and post VICP utilisation of 2%, have been modelled

for both scenarios (pre and post) with a utilisation of 100%; and

The two fire water pumps, which have a pre and post VICP utilisation of 2%, have been modelled

for both scenarios (pre and post) with a utilisation of 100%

This results in annual emissions well in excess of actual annual emissions which in turn results in

predicted annual ground level concentrations that are significantly higher than what would actually

occur. The main point to notice with the annual ground level concentrations is the introduction of

the expansion is only predicted to result in an insignificant increase (0.4µg/m3) in the annual

average.

For the cumulative scenario that model is predicting a minor increase of 1µg/m3 in the maximum

predicted 1-hour ground level concentrations. The model is also predicting an insignificant increase

of 0.3µg/m3 in the maximum annual NO2 concentration.



2 INTRODUCTION

2.1 Background


located off the Pilbara Coast in Western Australia (WA). This facility provides between 35 and 40 % of

WA's domestic gas supply. Apache needs to install two additional inlet gas compressors and an

additional power generator to ensure that production rates are not unduly influenced.

Pacific Environment Limited (PEL) has been engaged by Apache, to determine the potential impact

of the use of two additional turbine powered compressors and an additional power generator to

support the Varanus Island Compression Project (VICP). This potential impact to be determined is

based on the changes to air emissions and the relative significance of the change in emissions.

Previous atmospheric modelling for operational changes at Varanus Island have used the Victorian

EPA Gaussian plume model AUSPLUME and have concentrated solely on changes to ground level

concentrations of pollutants on the island itself. It is noted that the WA Department of Environment

and Conservation (DEC) raised concerns about the applicability of AUSPLUME in 2008 which was the

last atmospheric study completed on the operations at Varanus Island. For the current (2013)

assessment it is proposed to use the Commonwealth Scientific and Industrial Research Organisation

(CSIRO) model TAPM (The Air Pollution Model) version 4 which is consistent with other atmospheric

studies in the region.

2.2 Scope of Work

This project has consisted of three components. The first component is the preparation of a briefing

note to the WA DEC outlining the anticipated change in emissions from Varanus Island to determine

their requirements with respect to regional modelling. The remaining two components depended on

the WA DEC response on whether regional scale modelling is required or if just localised modelling is

sufficient.

As per the proposal, PEL has already completed the following activities:

Compiled a briefing note to the WA DEC Air Quality Management Branch (AQMB) outlining the

reason for the introduction of the two new compressors and the generator, potential change in

emissions of oxides of nitrogen (NOX), sulfur dioxide (SO2) and volatile organic compounds

(VOC). The aim of the briefing note is to inform the WA DEC that the increase in emissions is

minor and that cumulative regional photochemical modelling is not required;

Along with representatives of Apache PEL attended a meeting with personnel from the WA DEC

AQMB to determine the level of modelling that is required.

Based on the meeting with AQMB, it has been agreed that regional photochemical smog modelling

is not necessary as localised atmospheric modelling is already adequate to demonstrate the

potential impact of the additional turbo machinery proposed for the VICP. It is also agreed that the

increases in SO2 and VOC emissions are minor, only the emission of NOx is required in the modelling.

The specific activities that will be undertaken by PEL in the final part of this assessment include:

Local modelling: Model the existing and future emissions from the Apache operations on

Varanus Island to determine the potential change in ground level concentrations; and

Prepare a report containing the methodology and results of the modelled scenarios.



3 CLIMATE

Varanus Island is situated approximately 69 km WNW off the Pilbara coast of Western Australia.

Rainfall is low throughout the region and quite variable (Figure 3-1). Annual totals vary from 200 -

450mm, with many years without significant rainfall. The lower totals are typical of the years where

tropical cyclone effects are less frequent. Most of the summer rain comes from scattered

thunderstorms and the occasional tropical cyclone. A secondary peak in the monthly rainfall occurs

in May/June as a result of rainfall caused by tropical cloud bands which intermittently affect the

area mostly in these months. These events can also produce low maximum temperatures particularly

away from the coast. The number of thunderstorms average 20-30 per annum over most of the area

but 15-20 is more common near the coast. Almost all storms occur in the summer.

Figure 3-1: Monthly rainfall for Barrow Island -1967 to 2000 (source: Bureau of Meteorology)

The Pilbara region contains some of Australia's consistently hottest places, though the coast is 2-3°C

cooler but usually more humid due to the sea breezes. Winter maximum temperatures are

mild/warm with temperatures in the 23-27°C range in the south. Minimum temperatures range from

25°C in midsummer to 12°C in July near the coast (Figure 3-2).

January to March are the warmest months with average maximum temperatures of approximately

33°C. Winters are warm with average minimum temperatures of 17°C and maximum temperatures of

24°C in July.



Figure 3-2: Monthly temperature for Barrow Island - 1967 to 2000 (source: Bureau of Meteorology)

The long term humidity statistics in Barrow Island at 9 am and 3 pm are presented in Figure 3-3. This

figure shows that the humidity is consistent throughout the year, reflecting the effect of marine air

masses and seabreezes.

Figure 3-3: Monthly relative humidity for Barrow Island - 1967 to 2000 (source: Bureau of Meteorology)



The wind speed at 9 am averages 24 km/h (7 m/s) for the year, with June and November being the

windiest months on average. Wind speed at 3 pm also averages 24 km/h (7 m/s) with October to

January being the windiest months in the afternoon.

Average (1999 - 2013) wind roses for Barrow Island at 9 am and 3 pm are shown in Figure 3-4. The

morning (9 am) wind directions are predominantly from the east to southwest (approximately 80% of

the time), while afternoon winds (3 pm) are predominantly from the west to southwest and northeast

(approximately 83% of the time).



Figure 3-4: Climate wind roses for Barrow island for 9 am (upper) and 3 pm (lower) – 1999 to 2013

(source: Bureau of Meteorology).



4 AIR QUALITY GUIDELINES

This assessment considers the emissions that are associated with fuel combustion. A list of potential

substances has been screened for appropriateness to include in the assessment of the proposal. The

screening process for each substance considers whether the substance is emitted from the

proposal‘s specific activities, and if so, the quantity of substance emitted. Based on the outcome of

the screening process, the substance‘s emissions were either quantified and considered in dispersion

modelling, or quantified but considered insignificant and not included in the dispersion modelling.

Based on this analysis, oxides of nitrogen are considered to be the relevant emission for assessment.

Oxides of sulfur have been excluded from the assessment given the low sulfur content of fuel being

sourced.

The National Environment Protection Council (NEPC), now incorporated into the Environment

Protection and Heritage Council (EPHC), developed the Ambient Air Quality NEPM in 1998. In 2000,

the Western Australia Department of Environmental Protection (DEP) adopted the Ambient Air

Quality NEPM standards for general application to air quality management (WA EPA, 2001).

Consequently, predicted ambient ground-level concentrations will be assessed against these

standards. The relevant Air NEPM standards are listed in Table 4-1.

Table 4-1: NEPM Air quality goals relevant to this study

Species Averaging

Time ppm g/m3

Number of allowable exceedences

(under the NEPM)

NO2 1 hour 0.12 246 1 day a year

1 year 0.03 62 None



5 EMISSIONS ESTIMATION

5.1 Emission Sources

A review by Apache of the emission sources utilised in the previous modelling assessment (SKM 2008)

determined that they were out of date and were subsequently required to be updated. The current

emission sources for the Apache Varanus Island operations are listed in Table 5-1.

As well as containing the name and type of each emission source Table 5-1 also lists the operational

utilisation factor both before and after the proposed Varanus Island Compressor Project (VICP) for

each unit. This factor represents the percentage of time each year that each emissions source is

expected to be operational per year. Also presented in this table is the modelling utilisation factor

(UF) which highlights that even sources with a proposed utilisation of only 4%, such as the power

generation units ESJV-6001/6002, were modelled as operating continually (100%). This ensured that

the modelling process was very conservative.


conditions such as emergency shutdown or cold start up. The reason for this is that this is an existing

facility that is installing two additional turbine powered compressors and a single generator to

maintain capacity. Emissions from upset conditions will not change beyond that previously modelled

as there is no increase in production capability. As stated previously the modelling process is already

very conservative and the resulting increase in emissions from the upgraded facility is very low.

Table 5-1: Source characteristics - Existing

Name Tag No. Type

UF

(Pre

VICP)

UF

(Post

VICP)

Modelling

Utilisation

Factor

Power Generation

ESJV-6001 EG-6001 Reciprocating Gas Engines

(685 kW)

90% 4% 100%

ESJV-6002 EG-6002 90% 4% 100%

ESJV-6003 EG-6003 Centaur C40 Gas Turbine (3

MW) 96% 96% 100%

HJV-GT09 PGl-9 Saturn Gas Turbines (765 kW)

96% 96% 100%

HJV-GT10 PGl-10 96% 96% 100%

Black start Diesel Gensets EG-1 Reciprocating Diesel Engines

2% 2% 100%

Black start Diesel Gensets EG-2 2% 2% 100%

Turbine Driven Process Equipment

ESJV-SGCa K-6401-A

Taurus Gas Turbines (5.2 MW)

96% 96% 100%

ESJV-SGCb K-6401-B 96% 96% 100%

ESJV-SGCc K-6401-C 12% 12% 100%

ESJV-SG K-6401-D Mars 100 Gas Turbine (10.0 MW

at 30o C) 96% 96% 100%

HJV-SGC301 CM-11.301 Centaur Gas Turbines (2.33

MW)

96% 96% 100%

HJV-SGC302 CM-11.302 96% 96% 100%

HJV-SGCK12 K-12 Taurus T70 Gas Turbine (6.0

MW) 96% 96% 100%

GLC-K11A K-11A Taurus T60 Gas Turbines (4.0

MW)

50% 50% 100%

GLC-K11B K-11B 50% 50% 100%

WIP-G306 G-306 Centaur Gas Turbine (765 kW) 96% 96% 100%



Name Tag No. Type

UF

(Pre

VICP)

UF

(Post

VICP)

Modelling

Utilisation

Factor

Miscellaneous Equipment

Shipping pump G-101A

Diesel (295 kW)

2% 2% 100%

Shipping pump G-101B 2% 2% 100%

Shipping pump G-101C 2% 2% 100%

Other Processes Resulting in Emissions

New fire water pump (west) P-910A Diesel 2% 2% 100%

New fire water pump (east) P-910B Diesel 2% 2% 100%

HJV Elevated Flare F-101 Gas 100%

HJV Ground Flare F-100 Gas 100%

The proposed sources to be installed as part of the VICP are listed in Table 5-2 along with the

expected utilisation of the equipment and the utilisation used in this dispersion study.

Table 5-2: Source characteristics – Future (additional to Existing scenario)

Name Tag

No. Type Comment

UF

(Pre

VICP)

UF

(Post VICP)

Modelling

Utilisation

Factor

Power Generation

VICP Generator G-9001 Centaur C40 Gas

Turbine

Commencing

operation Q1

2015

96% 100%

Turbine Driven Process Equipment

VICP inlet compressor K0302 Mars 100 Gas

Turbine (10.5 MW

at 30°C)

Commencing

operation Q1

2015

96% 100%

VICP inlet compressor K0402 96% 100%

5.2 Emission Parameters

In order to assess potential impacts from the proposed development, four scenarios were modelled,

namely:

Existing scenario: Current emissions from the Apache operations on Varanus Island (see

Table 5-1);

Future scenario: Current emissions together with the equipment from VICP (see Table 5-1

and Table 5-2);

Cumulative existing scenario: Current emissions from the Apache operation on Varanus

Island together with existing and proposed emissions on Barrow Island; and



The emission summary for these scenarios is shown in the following sections.

5.2.1 Existing scenario

Emission characteristics for the existing scenario are presented in Table 5-3.



Table 5-3: Emission characteristics – Existing scenario

Source Tag Easting (m) Northing (m) Stack

Height

(m)

Internal

Stack

Radius

(m)

Temp

(K)

Exit

Velocity

(m/s)

NOX (as

NO2)

Emission

Rate (g/s)

ESJV-6001 EG-6001 351912 7715747 5 0.15 787 9.0 1.30

ESJV-6002 EG-6002 351915 7715750 5 0.15 787 9.0 1.30

ESJV-6003 EG-6003 351916 7715771 13 0.618 726 31.2 3.28

HJV-GT09 PGl-9 351980 7715820 9.2 0.55 805 30.0 0.78

HJV-GT10 PGl-10 351980 7715820 9.2 0.55 805 30.0 0.78

Black start Diesel Gensets EG-1 351912 7715747 6 0.10 782 106.6 2.33

Black start Diesel Gensets EG-2 351915 7715750 6 0.10 782 106.6 2.33

ESJV-SGCa K-6401-A 351914 7715783 13 0.8 573 23.0 4.42

ESJV-SGCb K-6401-B 351924 7715794 13 0.8 573 23.0 4.42

ESJV-SGCc K-6401-C 351942 7715813 13 0.82 573 21.9 4.42

ESJV-SG K-6401-D 351947 7715782 20.08 0.9 426 33.8 0.77

HJV-SGC301 CM-11.301 351970 7715855 13 0.7 573 24.0 3.18

HJV-SGC302 CM-11.302 351956 7715840 13 0.70 573 24.0 3.18

HJV-SGCK12 K-12 351950 7715829 12.1 0.71 543 34.4 7.91

GLC-K11A K-11A 352019 7715768 10.9 0.5 793 25.1 3.73

GLC-K11B K-11B 352035 7715752 10.9 0.5 793 25.1 3.73

WIP-G306 G-306 351984 7715764 7.5 0.5 731 47.5 3.18

Shipping pump G-101A 352044 7715772 3 0.15 793 46.3 1.54

Shipping pump G-101B 352040 7715776 3 0.15 793 46.3 1.54

Shipping pump G-101C 352037 7715779 3 0.15 793 46.3 1.54

New fire water pump (west) P-910A 351834 7715556 3.83 0.10 841 57.0 1.79

New fire water pump (east) P-910B 351840 7715556 3.83 0.10 841 57.0 1.79

HJV Elevated Flare F-101 351727 7715778 56.4 4.04 1273 20 5.7

HJV Ground Flare F-100 351716 7715727 40.2 73.8 1273 0.1 8.2

Note: Coordinates are provided as GDA 94 Zone 50

5.2.2 Future scenario

Emission characteristics for the future scenario (additional to the existing) are presented in Table 5-4.

This data was obtained from the technical specifications for the Mars and Centaur turbine

specifications as provided by Solar Turbines. It is recommended that stack testing be completed

during commissioning to confirm the emission parameters, including the emission rate of NO2.



Table 5-4: Emission characteristics – Future scenario (additional to existing scenario)

Name Tag Easting (m) Northing (m)

Stack

Height

(m)

Internal

Stack

Radius (m)

Temp

(K)

Exit

Velocity

(m/s)

NOX (as

NO2)

Emission

Rate (g/s)

VICP Generator G-9001 351895 7715692 9.8 0.57 726 8.8 0.76

VICP inlet compressor K0302 351812 7715795 12.8 1.3 772 16.2 2.06

VICP inlet compressor K0402 351798 7715780 12.8 1.3 772 16.2 2.06


5.2.3 Cumulative scenario

Emissions from Gorgon Gas Development on Barrow Island have also been included in this

assessment to determine the potential cumulative impact (SKM, 2005). Characteristics of these

emissions sources are presented in Table 5-5.

Table 5-5: Emission characteristics – Cumulative scenario (additional to existing and future scenario)

Easting (m) Northing (m) Stack Height

(m)

Internal Stack

Radius (m) Temp (K)

Exit

Velocity

(m/s)

NOX (as

NO2)

Emission

Rate (g/s)

Barrow Island (WA Oil)

332000 7697000 30.0 1.98 777 20.2 25.3

333200 7697045 30.0 1.98 777 20.2 25.3

Gorgon Gas Development (Chevron)

338372 7700255 40.0 2.25 692 34.5 17.9

338418 7700255 40.0 2.25 692 34.5 17.9

338464 7700255 40.0 2.25 692 34.5 17.9

338850 7700040 40.0 2.25 423 14.9 16.7

338850 7700040 40.0 2.25 423 14.9 16.7

338850 7700040 40.0 2.25 423 14.9 16.7

338850 7700040 40.0 2.25 423 14.9 16.7

338485 7700135 40.0 1.10 448 20 10

338485 7700135 40.0 1.10 448 20 10




5.3 Modelling Methodology

5.3.1 TAPM

The Air Pollution Model, or TAPM, is a coupled three dimensional meteorological and air pollution

model produced by the CSIRO Division of Atmospheric Research. It was released in late 1999.

The meteorological component of TAPM is an incompressible, non-hydrostatic, primitive equation

model. The model solves the momentum equations for horizontal wind components, the

incompressible continuity equation for vertical velocity, and scalar equations for potential virtual

temperature and specific humidity of water vapour, cloud water/ice, rain water and snow. Cloud

microphysical processes, turbulence kinetic energy, eddy dissipation and radiative fluxes are also

included (Hurley, 2008a).

The air pollution component of TAPM uses the predicted meteorology and turbulence from the

meteorological component and consists of:

A Eulerian Grid Module (EGM) to solve prognostic equations for the mean and variance of

concentration.

A Lagrangian Particle Module (LPM) to represent near-source dispersion more accurately.

A Plume Rise Module to account for plume momentum and buoyancy effects for point sources.

A Building Wake Module allows plume rise and dispersion to include wake effects on

meteorology and turbulence.

Gas-phase photochemical reactions based on the Generic Reaction Set, gas- and aqueous-

phase chemical reactions for sulfur dioxide and particles, and a dust mode for total suspended

particles (PM2.5, PM10, PM20 and PM30).

Wet and dry deposition (Hurley, 2008).

A number of changes have been made to the latest version of TAPM (V4). These include inter alia:

A global vegetation Leaf Area Index (LAI) database (monthly climatology) at 2-minute spatial

resolution has been added to the default databases.

A new surface layer scheme that includes an improved approach for very stable low wind

regimes has been incorporated into the model.

A new surface scheme that overcomes a number of limitations of the old surface scheme.

Two TAPM (V4) runs were performed for this study: The first coarse resolution simulation was to assess

cumulative (existing and expansion) impacts and the second, finer resolution run was to assess local

(existing and expansion) impacts due to emissions from the Apache facility in isolation. Modelling

was performed for the year 2010, and the TAPM specifications for this run were as listed in Table 5-6.



Table 5-6: TAPM Specifications for 2010 Simulations

Parameter Cumulative Apache VICP Only

Start date 31 Dec 2009 31 Dec 2009

End date 31 Dec 2010 31 Dec 2010

No. horizontal grid points per grid 40 x 40 30x30

No. vertical levels (nz) 20 20

Highest model level stored in output files nz-4 nz-4

No. grids 4 5

Horizontal grid spacing (meteorology) 30km, 10km, 3km and 1km 30km, 10km, 3km, 1km and 300m

Horizontal grid spacing (pollution) 75m

Centre latitude 20 43‘ S 20° 38.4‗ S

Centre longitude 115 28.5‘ E 115° 34.5‘ S

Local grid x co-ordinate at centre 340828 m E 351783 m N

Local grid y co-ordinate at centre 7707120 m E 7715647 m N

V4 TAPM land surface scheme Yes Yes

Non-hydrostatic pressure No No

Rain processes Yes Yes

Prognostic TKE and eddy dissipation Yes Yes

Emission File Yes Yes

The modelling input (including *.pse) files are provided electronically.

5.3.2 Merging Multiple Stacks

A plume released into an atmospheric cross flow undergoes mixing and dilution with the ambient air

due to complex turbulence processes. As a consequence the concentration of the contaminant will

vary in space and time, even for a steady state release. When plumes are released in close proximity

to each other there is an added complexity due to the potential interaction and merging of the

plumes, which may increase plume rise significantly through reduced entrainment and increased

buoyancy, (Hanna et al., 1982).

Briggs (1974) developed an empirical enhancement factor (EN) to account for increased plume rise.

The EN is defined as the ratio of the plume rise from N stacks to that from one stack (Hanna et al.,

1982, Manins et al., 1992):

3/1

1

S

SNEN

where

2/3

3/1

)1(6

hN

xNS

x is spacing between stacks and h is the final rise of a buoyant plume (Briggs, 1974). In TAPM the

buoyancy enhancement factor is considered and is input by the user (see Hurley, 2008b).



A number of stacks at the Varanus Island facility are close to each other, resulting in the potential for

plumes to merge. The buoyancy enhancement factors were calculated for each source based on

the above equations, and are presented in Table 5-7 below.

Table 5-7: Buoyancy enhancement factor

Source ID Enhancement Factor (EN)

Existing

ESJV-6001 1.09

ESJV-6002 1.09

ESJV-6003 1.01

HJV-GT09 1.26

HJV-GT10 1.26

EG-1 1.21

EG-2 1.21

ESJV-SGCa 1.23

ESJV-SGCb 1.23

ESJV-SGCc 1.20

ESJV-SG 1.18

HJV-SGC301 1.20

HJV-SGC302 1.20

HJV-SGCK12 1.23

GLC-K11A 1.18

GLC-K11B 1.18

WIP-G306 1.00

G-101A 1.19

G-101B 1.19

G-101C 1.21

P-910A 1.15

P-910B 1.15

Future

G-9001 1.00

K0302 1.24

K0402 1.24

5.3.3 Modelling Flares

As stated in Section 5.1 upset conditions, such as emergency shutdown, have not been modelled in

this assessment and therefore only emissions from the normal operations of flares have been

calculated.

Plume rise from flares is modelled similarly to point sources (e.g. stacks), with the exception of the

necessity to calculate release height as an effective release height and stack parameters to match

the (radiative-loss reduced) buoyancy flux (USEPA, 1992; OME, 2005).

Due to the high temperatures of flares, the effective release height is:



where Hsl = effective flare height (m), Hs = stack height above ground (m) and Hr = net heat

release rate (K/s), calculated by:

where V = flare volumetric flow rate (m3/s), fi the volume fraction of each gas component, H i the net

heating value of each component (J/g-Mol) and Fr the fraction of radiative heat loss (0.55%

according to the USEPA, 1992).

The equivalent flare diameter is estimated to account for plume buoyancy by solving for r in the

following equation (OME, 2005).

where Vs is stack exit velocity (m/s), Ts is stack temperature (K), T is ambient temperature, g is gravity

and F is buoyancy flux, given by:

As a worst-case scenario, it was assumed that flares operated simultaneously and continuously. The

parameters utilised in the plume rise modelling are presented in Table 5-8.

Table 5-8: Flare parameters for modelling (source: Apache Northwest Pty Ltd)

Source ID

Stack

Height

(m)

Temperature1

(K)

Exit

Velocity at

flare tip1

(m/s)

Effective2

flare Height

(m)

Effective

Flare

diameter

(m)

Heat

release

rate

(MJ/s)

NOX (as

NO2)

Emission

Rate (g/s

HJV Elevated

Flare F-101 35.2 1,273 20 56.4 4.04 197.3 5.7

HJV Ground

Flare F-100 15.0 1,273 20 40.2 73.8 282.8 8.2

1. USEPA, 1992 2. Note that this effective flare height is to account for the very high thermal buoyancy

5.3.4 NOX to NO2 Conversion

One of the most common atmospheric chemistry issues regulatory modellers are required to address

is estimating NO2 from modelled NOx concentrations. The amount of NO2 in the exhaust stream as it

is released from combustion sources is in the order of 5-10% of the NOx. To compensate for the

transformation of NO to NO2 that occurs after the exhaust gases are discharged, modellers have

adopted the following methods to estimate nitrogen dioxide concentrations:

Total Conversion (or USEPA Tier 1) Method:

o In this conservative screening approach, predicted ground-level concentrations of total

NOx are assumed to exist as 100% NO2.

USEPA Tier 2 analysis:

o Assumes a 75% conversion of NOx to NO2 (USEPA, 2005).

Tier 3 analysis, including:



o Ozone limited method (OLM):

- The OLM is based on the assumption that approximately 10% of the NOx emissions are

generated as NO2 (AE, 2003). If the ozone concentration is greater than 90% of the

predicted NOx concentrations, all the NOx is assumed to be converted to NO2 otherwise

NO2 = O3 + 0.1* NOx.

o Ambient Ratio Method (ARM) a:

- If there is at least one year of monitoring data available for NOx and NO2 within the

airshed, an empirical NOx /NO2 relationship can be derived and used as an alternative

to the ozone limiting method (AE, 2003; USEPA, 2005; BCME, 2008). However, a site

specific ratio derived from maximum impact data can only be used to estimate NO2

impacts at receptors located within the same distance of the source as the source-to-

monitor distance (USEPA, 2005).

While TAPM uses a semi-empirical chemistry mechanism option (i.e. GRS) to determine NO2 formation, it

was decided to model NOx emissions as passive tracers and to use the OLM to estimate NO2

concentrations. Monitored and modelled ozone concentrations of 43 and 128 µg/m3 for annual

average and 1-hour maximum respectively were used to estimate NO2 concentrations (DEP, 2002;

CSIRO, 2004).

a A sophisticated methodology for the application of the ARM is provided in BCME (2008).



6 METEOROLOGICAL MODELLING

Meteorological data for 2010 was generated internally by TAPM. Features of the meteorology are

described below.

6.1 Wind

Wind speed and direction are highly important influences on plume dispersion. Wind direction

dictates the direction in which the plume travels. Thus, over a long period, the temporal variation of

wind directions determines the spatial pattern of average ground level concentrations. Wind speed

influences the initial dilution of the plume as it leaves the source and also affects plume rise, with

higher wind speeds resulting in smaller plume rise. Broadly, higher wind speeds result in lower ground

level concentrations.

The TAPM wind roses for 2010 are shown in Figure 6-1. The annual average wind rose shows a

dominance of south-westerly and easterly winds. Generally, the wind roses at 9am and 3pm show

similar to the climatological wind roses for Barrow Island (see Figure 3-4).

6.2 Atmospheric Stability

An important aspect of plume dispersion is the level of turbulence in the atmospheric boundary

layer. Turbulence acts to dilute or diffuse a plume by increasing the cross-sectional area of the

plume due to random motions. As turbulence increases, the rate of plume dilution, or diffusion,

increases. Weak turbulence limits diffusion and is a critical factor in causing high plume

concentrations downwind of a source.

Turbulence is related to the vertical temperature gradient, the condition of which determines what is

known as stability, or thermal stability. For traditional dispersion modelling using Gaussian plume

models, categories of atmospheric stability are used in conjunction with other meteorological data

to describe the dispersion conditions in the atmosphere. The best known stability classification is the

Pasquill-Gifford scheme, which denotes stability classes from A to F. Class A is described as highly

unstable and occurs in association with strong surface heating and light winds, leading to intense

convective turbulence and much enhanced plume dilution, as the strong turbulence acts to quickly

spread the plume apart. At the other extreme, class F denotes very stable conditions associated with

strong temperature inversions and light winds, such as commonly occur under clear skies at night

and in the early morning. Under these conditions plumes can remain compact and relatively

undiluted for considerable distances downwind. Intermediate stability classes grade from

moderately unstable (B), through neutral (D) to slightly stable (E). Whilst classes A and F are closely

associated with clear skies, the neutral class D is linked to windy and/or cloudy weather, and short

periods around sunset and sunrise when surface heating or cooling is small.

The frequency distribution of estimated PG stability classes presented in Figure 6-2 gives an idea of

the degree of modelled turbulence of the atmosphere over Varanus Island. The data show a

relatively low proportion of A and B (unstable) and E and F (stable) class. Stability class C and D

dominate, occurring for 55% of the time. This is consistent with the oceanic location of the site.



Figure 6-1: Annual (top left), 9am (top right) and 3 pm (bottom) wind roses at Varanus Island for 2010



Figure 6-2: Frequency distribution of Pasquill-Gifford stability class at Varanus Island for 2010

6.3 Mixing Height

Mixing height is defined as a temperature inversion or statically stable layer of air capping the

atmospheric boundary layer where an emitted or entrained tracer will be mixed by turbulence

(Beyrich, 1997). It is often associated with, or measured by, a sharp increase of temperature with

height (inversion), a sharp decrease of water-vapour, a sharp decrease in turbulence intensity and a

sharp decrease in pollutant concentration.

Mixing height is variable in space and time, and typically increases during fair-weather daytime over

land from tens to hundreds of metres around sunrise up to 1–4 km in the mid-afternoon, depending

on the location, season and day-to-day weather conditions.

Two different types of temperature inversion frequently develop and may lead to air pollution

episodes. These are:

radiation or surface inversions that form overnight through rapid cooling of the ground and

surface air layers; and

subsidence inversions that form at various heights above the ground due to subsiding air

associated with the anticyclone.

Radiation inversions are usually short-lived and rarely persist beyond mid-morning. Subsidence

inversions may persist for up to six days while the associated anticyclone is in the vicinity. Short

periods of severe air pollution can occur with radiation inversions but sustained pollution events result

from subsidence inversions.

The frequency of mixing heights in the meteorological dataset developed for this study is shown in

Figure 6-3. As expected, simulated mixing heights are lower during the night and early morning hours

(< 200 m), increasing after sunrise to under 400 m (90 percentile of 750 m) by mid-afternoon. This

pattern of a small diurnal cycle is again consistent with the oceanic location.



Figure 6-3: TAPM derived hourly mixing height statistics for Varanus Island for 2010

6.4 Model Validation

The accuracy of TAPM in generating meteorology for the dispersion model was assessed by

comparing selected modelled variables against corresponding hourly data measured at the Bureau

of Meteorology station at Barrow Island. Figure 6-4 to Figure 6-7 presents hourly measured and

corresponding modelled wind components and temperature for January 2010 – December 2010.

Figure 6-4 shows a comparison between hourly average measured and modelled u-component of

windb. The model tends to under predict westerly wind components (+ve values) more than easterly

components (-ve).

The scatter plot of modelled versus measured hourly v-componentc of wind is shown in Figure 6-5.

Through visual inspection, it is obvious that the model significantly under predicts this wind

component. Note the anomalous pattern aligned to zero for monitoring data for both u- and v-

components. This is most likely a function of the stalling speed / restart threshold of the Bureau of

Meteorology anemometer at Barrow Island.

Figure 6-6 and Figure 6-7 shows scatter plot and frequency plot of measured and corresponding

modelled temperature, respectively. Although the model slightly under predicts maximum

temperature and over predicts minimum temperatures, it generally performs adequately for this

parameter.

b U component represents the east-west component of the wind

c V component represents the north-south component of the wind



Figure 6-4: Scatter plot of hourly modelled versus measured u-component of wind

Figure 6-5: Scatter plot of hourly modelled versus measured v-component of wind



Figure 6-6 Scatter plot of hourly modelled versus measured temperature

Figure 6-7 Frequency plot of hourly modelled versus measured temperature



6.5 Statistical Measures of Model Performance

A more objective method to evaluate model performance is through the use of statistical tests that

have been developed for this purpose. These tests are, inter alia, geometric mean, geometric

variance, model bias, fraction bias, normalised mean square error, root mean square error, Skill_v, Skill_r,

index of agreement and the coefficient of correlation.

6.5.1 Geometric Mean

The geometric mean is a type of mean or average, which indicates the central tendency or typical

value of a set of numbers. The MG test is given by:

Where:

O = the average observed (measured) value

P = the average predicted (modelled) value

A model is considered to be acceptable if the geometric mean is between 0.7 and 1.3 (Chang and

Hanna, 2004).

6.5.2 Geometric Variance

The geometric variance test is given by:

Where:

O = the average observed (measured) value

P = the average predicted (modelled) value

A model is considered to be acceptable if the geometric variance is less than 1.6 (Chang and Hanna,

2004).

6.5.3 Skill_r

The Skill_r test is the ratio of RMSE to observed standard deviation:

Skill rN

P O

O

i ii

N

std

_

( )

1 2

1

Where:

N = the number of pairs of data

Oi = the observed (measured) value for the i-th hour



Pi = the predicted (modelled) value for the i-th hour

Ostd = the standard deviation of measured data.

A model is considered to be predicting with skill if the RMSE is less than the standard deviation of the

observations (Skill_r <1) (Pielke, 1984; Hurley, 2000).

6.5.4 Skill_v

Skill vP

Ostd

std

_

Where:

Pstd = the standard deviation of predicted data

Ostd = the standard deviation of observed data.

A model is considered to be predicting with skill if the standard deviations of the predictions and

observations are the same (Skill_v = 1) (Pielke, 1984; Hurley, 2000).

6.5.5 Model Bias

The model bias (MB) is the mean error and is given by:

n

iii PO

nMB

1

1

Where:

n = the number of pairs of observed data

Oi = the observed value for the i-th hour

Pi = the predicted value for the i-th hour

The ideal value for the bias is zero.

6.5.6 Fraction Bias

The fraction bias (FB) is a normalised index of model performance and is expressed by:

PO

POFB

2

Where:

O = the average observed values

P = the average predicted values



The FB varies between +2 and –2 and has an ideal value of zero. FB values of ±0.67 correspond to a

prediction within a factor of 2.

6.5.1 Root Mean Square Error (RMSE)

The Root mean Square Error is given by:

n

iii PO

nRMSE

1

21

Where:

N = the number of pairs of data

Oi = the observed (measured) value for the i-th hour

Pi = the predicted (modelled) value for the i-th hour

While the ideal RMSE value is 0, large errors in a small section of the data may produce a large RMSE

even though errors may be small elsewhere.

6.5.2 Index of Agreement

The index of agreement (IOA) is the measure of how well the model estimates departure from the

observed mean matches cases by case, the observations departure from the observed mean:

n

iii OOOP

RMSENIOA

1

2

2

1

Where:

n = the number of pairs of observed data

Oi = the observed value for the i-th hour

Ōi = the mean observed value

The ideal value for IOA is one.

A set of benchmarks were set for mesoscale model evaluation by Emery et. al (2001) and Teschke et. al

(2001). These are listed in the table below:



Table 6-1: Mesoscale model benchmarks (after Emery et al, 2001; Teschke et al, 2001)

Parameter Test Benchmark

Wind Speed

Gross Error 2 m/s

BIAS ± 0.5 m/s

IOA 0.6

Temp

Gross Error 2 K

BIAS ± 0.5 K

IOA 0.8

Wind Direction Gross Error 30 °

BIAS 10 °

The results of the statistical model verification are shown in Table 6-2. Temperature meets most of the

validation benchmarks or statistical criteria. The model does not pass all the performance criteria or

statistical measures for wind speed. This is confirmed when the wind components are assessed.

For wind direction the validation benchmarks listed in Table 6-1 are met. Overall, it can be statistically

concluded that TAPM simulates wind direction and temperature with an acceptable degree of skill,

but does not perform as well for wind speed.

Table 6-2: Results of statistical test: Summer

MG GV MB FB Skill_v Skill_r r IOA Gross Error

Ideal

Score

0.7-1.3 <1.6 See

Table

6-1

±0.67 <1.0 0 1 See

Table

6-1

1 and See

Table 6-1

Temp. 0.98 1.00 -1.11 -0.02 0.82 0.38 0.85 0.72 1.72

Wind Spd. 1.73 1.35 3.01 0.54 0.61 2.38 0.76 0.74

u-comp 2.38 2.11 2.31 0.81 0.60 0.77 0.87 0.82

v-comp 1.04 1.00 0.27 0.04 0.50 0.14 0.78 0.79

Wind Dir. 0.36 18.75



7 MODEL RESULTS

The results of the atmospheric dispersion modelling using the emission parameters outlined in Section 5.2

and the model setup outlined in Section 5.3 are contained in the following sections.

7.1 Varanus Island

The maximum predicted ground level concentrations for NO2 for both the existing and proposed VICP

scenarios are presented in Table 7-1. From this table it is apparent that the introduction of the additional

sources associated with VICP are predicted to result in a minor increase in the maximum predicted 1-

hour ground level concentrations.

Table 7-1: Maximum predicted ground level concentrations of NO2 on modelled grid for Varanus Island

Averaging Period Scenario Maximum

(µg/m3)

Criteria

(µg/m3)

Percentage of

Criteria


Expansion 214 246 87.0%

Annual Existing 75.3 62 121.5%

Expansion 75.7 62 122.1%

For the annual predicted ground level concentrations the model is predicting that the maximum will be

above the NEPM criteria of 62 µg/m3. However it should be noted that this is primarily due to the very

conservative emission rates used in the model whereby all sources are modelled as occurring for every

hour of the year. The utilisation factor for each existing emission source is contained within Table 5-1

and is outlined below for sources with low utilisation:

The ESJV reciprocating gas engines have a pre-VICP utilisation of 90% and a post-VICP of 4% though

they have been modelled for both scenarios (pre and post) with a utilisation of 100%

The black start diesel generators have a pre-VICP utilisation of 2% and a post-VICP of 2% and they

have been modelled for both scenarios (pre and post) with a utilisation of 100%

One of the Taurus Gas Turbines has a pre and post VICP utilisation of 12% and has been modelled


The Taurus T60 gas turbines have a pre and post VICP utilisation of 50% and have been modelled for

both scenarios (pre and post) with a utilisation of 100%

The three shipping pumps, which have a pre and post VICP utilisation of 2%, have been modelled


The two fire water pumps, which have a pre and post VICP utilisation of 2%, have been modelled for

both scenarios (pre and post) with a utilisation of 100%

This results in annual emissions well in excess of actual annual emissions. This in turn results in predicted

ground level concentrations significantly higher than what would actually occur. The main point to

notice with the annual ground level concentrations is the introduction of the expansion is only

predicted to result in an insignificant increase in the annual average.



7.1.1 Existing

The maximum predicted 1-hour NO2 ground level concentrations for the existing scenario (Varanus

Island only) are presented in Figure 7-1 and the maximum predicted annual average NO2 ground level

concentrations for the existing scenario (Varanus Island only) are presented in Figure 7-2. Note again

that the emission rates used in this assessment for Varanus Island are extremely conservative and would

not represent the true emissions from the facility, especially on an annual basis, and hence do not

accurately reflect the true ground level concentrations in the immediate region.


(Varanus Island) (µg/m3)



Figure 7-2 Predicted annual averaged NO2 ground level concentrations for the existing scenario


7.1.2 Expansion

The maximum predicted 1-hour NO2 ground level concentrations for the expansion scenario (Varanus

Island only) are presented in Figure 7-3 and the predicted annual average NO2 ground level

concentrations for the expansion scenario (Varanus Island only) are presented in Figure 7-4. Again it is

important to note that the emission rates used in this assessment for Varanus Island are extremely

conservative and would not represent the true emissions from the facility, especially on an annual basis,

and hence do not accurately reflect the true ground level concentrations in the immediate region.



7.2 Cumulative

The maximum predicted cumulative ground level concentrations for NO2 for both the existing and

proposed VICP scenarios are presented in Table 7-2. This scenario includes from the existing WA Oil

emissions on Barrow Island along with the emissions from the Chevron Gorgon facility which is currently

under construction. From this table it is apparent that the introduction of the additional sources

associated with VICP are predicted to result in a minor increase in the maximum predicted 1-hour

ground level concentrations.

The model is also predicting an insignificant increase in the maximum annual NO2 concentration.

When the annual average NO2 ground level concentration presented in Table 7-2 is compared to that

presented in Table 7-1 it is apparent that there has been a reduction in the maximum predicted

concentration. This is primarily due to the larger but coarser grid used for the cumulative modelling.

The previous comment regarding the very conservative emission rates used in the model are still valid

(Section 7.1).

Table 7-2: Maximum predicted ground level concentrations on modelled grid for the cumulative

scenario

Averaging Period Scenario Maximum

(µg/m3)

Criteria

(µg/m3)

Percentage of

Criteria


Expansion 183 246 74.4%

Annual Existing 55.3 62 89.2%

Expansion 55.6 62 89.7%

7.2.1 Existing

The maximum predicted 1-hour NO2 ground level concentrations for the existing cumulative scenario

are presented in Figure 7-5 and the maximum predicted annual average NO2 ground level

concentrations for the existing cumulative scenario are presented in Figure 7-6. Note again that the

emission rates used in this assessment for Varanus Island are extremely conservative and would not

represent the true emissions from the facility, especially on an annual basis, and hence do not

accurately reflect the true ground level concentrations in the immediate region.




(cumulative) (µg/m3)



Figure 7-6 Predicted annual average NO2 ground level concentrations for the existing scenario


7.2.2 Expansion

The maximum predicted 1-hour NO2 ground level concentrations for the cumulative expansion

scenario are presented in Figure 7-7 and the predicted annual average NO2 ground level

concentrations for the cumulative expansion scenario are presented in Figure 7-8. Again it is important

to note that the emission rates used in this assessment for Varanus Island are extremely conservative

and would not represent the true emissions from the facility, especially on an annual basis, and hence

do not accurately reflect the true ground level concentrations in the immediate region.



8 CONCLUSION


located off the Pilbara Coast in Western Australia (WA). This facility provides between 35 and 40 % of

WA's domestic gas supply. To ensure that production rates are not unduly influenced Apache is seeking

to install two additional inlet gas compressors and an additional power generator at this facility.

Pacific Environment Limited (PEL) has been engaged by Apache, to determine the potential impact of

the use of the two compressors additional turbine powered compressors and an additional power

generator to support the Varanus Island Compression Project (VICP). This potential impact to be

determined is based on the changes to air emissions and the relative significance of the change in

emissions.

Discussions with the AQMB determined that regional photochemical smog modelling is not necessary

as localised atmospheric modelling should be adequate to demonstrate the potential impact of the

very minor increase in NO2 resulting from the project. It is also agreed that the increases in SO2 and

VOC emissions are insignificant.

Previous atmospheric modelling for operational changes at Varanus Island have used the Victorian EPA

Gaussian plume model AUSPLUME and have concentrated solely on changes to ground level

concentrations of pollutants on the island itself. As the WA DEC had previously noted concerns about

the applicability of this model the CSIRO model TAPM (version 4) was utilised which is consistent with

other atmospheric studies in the region.


conditions such as emergency shutdown as this is an existing facility that is not increasing capacity.

Emissions from upset conditions will not change beyond that previously modelled as there is no increase

in production capability.

A review by Apache also determined that the emission sources modelled in the previous 2008

assessment were out of date and were subsequently updated. Using this data four scenarios were

modelled to assess potential impacts from the proposed development namely:

Existing scenario: Current emissions from the Apache operations on Varanus Island;

Future scenario: Current emissions together with the equipment from VICP;

Cumulative existing scenario: Current emissions from the Apache operation on Varanus Island

together with existing and proposed emissions on Barrow Island; and



The results of the modelling for the Varanus Island operations as a standalone facility determined that

the introduction of the additional emissions associated with VICP would only result in an increase of

1µg/m3 in the maximum predicted 1-hour ground level concentrations.

For the annual average the model predicted that the maximum will be above the NEPM criteria of

62µg/m3. This is primarily due to the very conservative emission rates used in the model whereby all

sources are assumed to be operating all the time. This is an incorrect assumption as some sources will

be operating at much lower frequencies. An example of this is the shipping pumps which will only be

operational for 2% each year. This results in predicted annual ground level concentrations that are

significantly higher than what would actually occur. The main point to notice with the annual ground

level concentrations is the introduction of the expansion is only predicted to result in an insignificant

increase (0.4µg/m3) in the annual average.



For the cumulative scenario that model is predicting a minor increase of 1µg/m3 in the maximum

predicted 1-hour ground level concentrations. The model is also predicting an insignificant increase of

0.3µg/m3 in the maximum annual NO2 concentration.



9 REFERENCES

AE 2003. Air Quality Model Guideline, Alberta Environment, Publication No. T/689, Canada

BCME 2008. Guidelines for Air Quality Dispersion Modeling in British Columbia, British Columbia Ministry of

Environment, Environmental Protection Division, Canada.

Beyrich, F 1997. Mixing height estimation from sodar data: A critical discussion. Atmos. Environ, 31:3941–

3953

Briggs G A 1974. Plume rise from multiple sources. In Cooling Tower Environment – 1974, S R Hanna and J

Pelks (Eds), University of Maryland Education Centre, 4-6 March 1974, NTIS CONF – 740302, pp161-179.

Chang, J., and S. Hanna, 2004: Air quality model performance evaluation. Meteor. Atmos. Phys., 87,

167–196.

CSIRO 2004. Summary of TAPM Verification for the Pilbara Region. A Report to the Department of

Environment, WA. March 2004.

DEP 2002. Monitoring of ambient air quality and meteorology during the Pilbara Air Quality Study.

Technical Series 113, Department of Environmental Protection, Perth, Western Australia, September

2002.

Emery, C., E. Tai, and G. Yarwood, 2001. ―Enhanced Meteorological Modeling and Performance

Evaluation for Two Texas Ozone Episodes‖, report to the Texas Natural Resources Conservation

Commission, prepared by ENVIRON, International Corp, Novato, CA.

Hanna, S.R., Briggs, G.A. and Hosker, R.P. 1982. Handbook on Atmospheric Diffusion, US Department of

Energy.

Hurley, P.J., 2000: Verification of TAPM meteorological predictions in the Melbourne region for a winter

and summer month. Aust. Met. Mag., 49, 97-107

Hurley P.J. 2008a. TAPM V4 User Manual. CSIRO Marine and Atmospheric Research Internal Report No 5.

October 2008.

Hurley, P. J. 2008b. The Air Pollution Model (TAPM) Version 4: User Manual. Aspendale: CSIRO

Atmospheric Research. (CSIRO Atmospheric Research internal paper; 25). 38 p

Manins, P.C., Carras, J.N. and Williams, D.L 1992. Plume Rise from Multiple Stacks, Clean Air, 26(2), 65-68.

OME 2005. Air Dispersion Modelling Guideline for Ontario, Ontario Ministry of the Environment, PIBS

5165e.

Pielke, R.A, 1984: Mesoscale Meteorological Modelling. Academic Press. Orlando, USA.

SKM, 2005: The Gorgon Gas Development Air Quality Assessment prepared for Chevron Texaco

Australia Pty Ltd

Tesche, T. W., D. E. McNally, C. A. Emery, and E. Tai, 2001: ―Evaluation of the MM5 Model Over the

Midwestern U.S. for Three 8-Hr Oxidant Episodes‖, prepared for the Kansas City Ozone Technical Work

Group, prepared by Alpine Geophysics, LLC, Ft. Wright, KY and ENVIRON International Corp., Novato,

CA.



US EPA 1992. Screening Procedures for Estimating the Air Quality Impact of Stationary Sources, United

States Environmental Protection Agency, EPA-454/R-92-019.

USEPA 2005. Appendix W to Part 51—Guideline on Air Quality Models, Environmental Protection Agency

Pt. 51, App. W. United Stated Environmental Protection Agency.

WA DEC 2001. Towards and Environmental Protection Policy (EPP) for ambient air quality in Wstern

Australia, Environmental Protection Authority.

Santos Ltd | Varanus Island Compression and Power Optimisation Project – Works Approval Supporting Document Page 82 of 82

Appendix 7 – Works Approval W5518/2013/1

1

Phillips, Nick

From:Sent: Monday, 11 November 2013 8:07 AMTo: Poor, SonyaCc: Wyeth, Harry; Project, VICompSubject: FW: VICP works approval questions (Response)Attachments: VICP Plant Area_Boundary Definition Points_Rev 0.xlsx

Hi Sonya, Thanks for your enquiries. Clarifications are as per the attached and as indicated in red below. Regards Nick

From: Poor, Sonya Sent: Friday, 8 November 2013 12:54 PM To: Phillips, Nick Cc: Wyeth, Harry Subject: VICP works approval questions Hi Nick, I am just reviewing the works approval application for the Varanus Island Compression Project. Can you please address the following:

‐ Coordinates for the premises boundary of the Varanus Island works area? Refer to coordinates as attached.

‐ How long does Apache require to commission the VICP under the works approval (we

generally give 3 months)? Three months is sufficient for the envisaged commissioning works.

‐ UHC page 56 is this unburnt hydrocarbons? Correct.

Thanks for your help. Update on application – currently at 41 days, once I have finished my review will go to Regional Leader for review, then Perth for review, then to Apache for comment prior to final issuing. Regards,

Sonya Poor Environmental Officer Industry Regulation - Pilbara Region

www.der.wa.gov.au

1

Phillips, Nick

From: Phillips, Nick Sent: Tuesday, 10 September 2013 4:11 PMTo: Poor, SonyaSubject: FW: Varanus Island Compression Project works approval questions [Apache

Response]Attachments: Solar Turbines_Combustion Technology Info.pdf

Importance: High

Hello Sonya Please find below the requested information in blue. Apache is ready to pay the DER invoice once received. We look forward to your reply on this matter. Kind Regards Nick Phillips Environmental Scientist

This email including any attachments contains confidential information. Only the intended recipient may access or use the information transmitted. If you are not the intended recipient please notify the sender by reply email and delete this email.

From: Poor, Sonya Sent: Friday, 6 September 2013 12:55 PM To: Hopkinson, Minh Cc: Phillips, Nick Subject: RE: Varanus Island Compression Project works approval questions This application will be placed on hold until the requested information is received. Regards,

Sonya Poor Environmental Officer Industry Regulation - Pilbara Region Department of Environment Regulation

From: Poor, Sonya Sent: Friday, 6 September 2013 12:50 PM To: 'Hopkinson, Minh' Cc: 'Phillips, Nick' Subject: Varanus Island Compression Project works approval questions

2

Hi, I am just reviewing Apache’s Varanus Island Compression Project works approval supporting documentation and have the following questions: P36 under the dot point Two HPDE lined: it states “use of clarified water from the slurry pits is not intended as a primary source of dust suppression water and the clarified water will be diluted with potable water prior to use”.

1) Use for what – dust suppression, should this read ‐ is intended as a primary source of dust suppression...?

No. Potable water will be the primary water source for dust suppression. Clarified water will be drawn from the slurry pits to maintain the design freeboard as the need arises. The clarified water will be diluted with potable water used for dust suppression. This process will be managed in accordance with the Department of Mines and Petroleum (DMP)‐approved Construction Environmental Management Plan (CEMP) and all ‘discharges’ will comply with the Environmental Protection (Unauthorised Discharge) Regulations. P38 – under stormwater and site drainage: Oily water separator (OWS) designed to capture and retain TSS down to 10µm and up to 98% of free oils from the inlet screen

2) what will the OWS treat total petroleum hydrocarbons down to (mg/L)?

The proposed Humeceptor OWS has performance characteristics as follows:

Upstream TPH11 Concentration2

(ppm)

Downstream TPH11

Concentration3

(ppm)

% Removal efficiency4

48 1.3 97.2%

1,946 8 99.6%

Notes

1. TPH = Total Petroleum Hydrocarbons.

2. Apache expects the upstream concentration of TPH entering the Humeceptor to vary between approximately 50ppm (routine operations as P90 event) and 2,000ppm (non‐routine operations as P10 event).

3. Downstream concentration is at the Humeceptor outlet.

4. Removal efficiencies are based upon continuous full (maximum) treatment flow rate to reflect relatively extreme field conditions.

5. The concentrations provided as ppm (by volume) are offered as the industry standard rather than mg/L that has inherent difficulties when dealing with upstream and downstream flows comprising variable specific gravities i.e. water and TPH.

Treated discharge water will be piped to the existing HDPE lined retention basin 1. what happens to the water from here?

The existing HDPE lined retention basin is effectively an evaporation basin. If sufficient water run‐off quantities are generated by a storm event, discharge will occur from the pond into the existing drainage lines on the lease land adjacent to the ESJV gas plant as is

3

currently the case. The retention pond is sized to allow settlement of and to prevent carry over sediment prior to discharge into existing drainage lines within the Apache lease area.

P63 states “the retention pond is sized to allow settlement..... prior to discharge into existing drainage lines within the Apache lease area” 2. is this in relation to the pond in Q3?

Yes.

3. is the water in the ponds tested prior (TPH etc) to discharge?

No. Discharge only occurs as overflow during a storm event.

P52 – washdown products from the concrete batching facility and trucks: States ...only if quality sampling is undertaken to confirm washdown water discharge is compliant with the EP (Unauthorised Discharges) Reg 2004 4. what about the Department of Water, Water Quality Protection Note 68 – Mechanical

equipment washdown, March 2006?

To clarify, the slurry pits will only contain water used to washout concrete agitators and delivery chutes, i.e. external surfaces and mechanical parts of agitator trucks will not be subject to washdown at this location. In reference to Table 1 in the protection note, Apache commits to a pH range of 5.5 to 8.5 and salinity level of less than 1800 uS/cm. No surfactants, petroleum hydrocarbons or BTEX will be in the washdown water; hence, these will not be tested. Apache does not plan to test for ‘other toxic soluble contaminants’ as stated in the table. Apache will, however, ensure compounds or solutions of cyanide, chromium, cadmium, lead, arsenic, mercury, nickel, zinc or copper are not discharged to the environment; as per the regulations. P56 8.1.2 Management controls ‐ dry‐low NOx burners within each turbine using Solar Turbine proprietary SoLoNOx technology to reduce NOx combustion emissions P78 shows explains how the SoLoNOx works ‐ 5. can you provide a brief description on the dry low NOx burners?

The attached overview prepared by Solar Turbines provides additional information on:

Gas turbine Combustion Systems & Emissions; and

Dry Low Emissions (DLE) Combustion.

Key points are that DLE combustion is achieved by: creating a lean pre‐mixed fuel supply (i.e. lowering the fuel air ratio), creating a lean combustion environment, eliminating combustion hot‐spots, lowering the combustion flame temperature and increasing the combustion residence time.

Previous advice I have received from the DER Process Industries Sector is that it is recommended that new plants should be able to meet best practice emission standards. 6. Will the compressors and generators be able to achieve the emissions standards from

the UK Environment Agency – How to comply with your environmental permit, additional guidance for Combustion Activities (EPR 1.01)?

Based upon turbine performance runs conducted for the Mars 100 (compressor engine) and the Centaur 40 (generator engine), as undertaken by Solar Turbine in June 2013, results were as follows:

SO2 NOx CO Notes

4

(mg/m3) Note 4

(mg/m3)Note 4

(mg/m3)Note 4

Emission Standards1

10 20‐50 100 None

Emission Criteria2

‐ 70 125 None

Mars 1003 – as per performance run.

<10 70

Note 5 92

The Mars 100 achieves the EPR 1.01 Annexure 1 – Emission Benchmarks for SO2 and CO. NOx value in excess by approximately 20 mg/m3. The Mars 100 meets the emissions criteria stated within the NSW Protection of the Environment Operations (Clean Air) Regulations 2010.

Centaur C403 – as per performance run.

<10 60

Note 5 92

The Centaur C40 achieves the EPR 1.01 Annexure 1 – Emission Benchmarks for SO2 and CO. NOx value in excess by approximately 10 mg/m3. The Centaur C40 also meets the emissions criteria stated within the NSW Protection of the Environment Operations (Clean Air) Regulations 2010.

Notes

1. EPR 1.01 Annexure 1 – Emission Benchmarks; UK Environment Agency.

2. NSW Protection of the Environment Operations (Clean Air) Regulations 2010.

3. Performance runs at 100% load and 11oC ambient (i.e. combustion inlet temperature).

4. Achievable concentrations, mg/m3, dry at 0oC, 101.3 kPa.

5. Actual NOx values are to be validated during turbine stack emissions monitoring as per Section 8.1.5 of Apache’s “Works Approval – Supporting Documentation” (Doc. Ref: JB‐10‐RG‐178)

From the Application Enquiry Form it stated that the WWTP would be upgraded ‐ Is this still going ahead? No. If so, please include information on:

expected treated wastewater quality;

sludge storage and disposal, including frequency of removal; and

will the WWTP operate in accordance with L6284/1992/9? Regards,

Sonya Poor Environmental Officer Industry Regulation - Pilbara Region

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