Neath Port Talbot Sandfields Secondary School

BREEAM Ene04 LZC Feasibility Study

Submitted by AECOM 1 Callaghan Square Cardiff CF10 5BT

Neath Port Talbot Sandfields Secondary School Low & Zero Carbon Technologies Feasibility Study Report for BREEAM 2014 Ene04

October 2016

Neath Port Talbot – Sandfields School – BREEAM Ene04 LZC Feasibility Study Report Page ii

BREEAM Ene04 LZC Feasibility Study Report October 2016

Prepared by: ..................... Checked by: ....................... Jacob Loh Jonathan Milne Graduate Sustainability Consultant Mechanical Engineer

Approved by: ....................... Simon Hartley Regional Director

Rev No Comments Checked by Approved by Date

0.1 - 0.3 Internal drafts for QA JM

1.0 Final draft pending client feedback JM SH 25/10/16

1 Callaghan Square, Cardiff, CF10 5BT, United Kingdom T +44 (0)2920 674600 www.aecom.com Job No: 60486628 Date created: 25/10/2016

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Limitations

This document has been prepared in accordance with the scope of AECOM Ltd.’s (AECOM) appointment with AHR and their appointment with Swansea University (Client) and is subject to the terms of that appointment. It is addressed to and for the sole and confidential use of AECOM’s client. AECOM accepts no liability for any use of this document other than by its client and only for the purposes for which it was prepared and provided. No person other than the client may copy (in whole or in part) or rely on the contents of this document, without the prior written permission of the Company Secretary of AECOM. Any advice, opinions, or recommendations within this document should be read and relied upon only in the context of the document as a whole. The contents of this document do not provide legal or tax advice or opinion.

The conclusions and recommendations contained in this Report are based upon information provided by others and upon the assumption that all relevant information has been provided by those parties from whom it has been requested and that such information is accurate. Information obtained by AECOM has not been independently verified by AECOM, unless otherwise stated in the Report.

The methodology adopted and the sources of information used by AECOM in providing its services are outlined in this Report. The work described in this Report was undertaken in the period stated and is based on the conditions encountered and the information available during the said period of time. The scope of this Report and the services are accordingly factually limited by these circumstances.

Where assessments of works or costs identified in this Report are made, such assessments are based upon the information available at the time and where appropriate are subject to further investigations or information which may become available.

AECOM disclaim any undertaking or obligation to advise any person of any change in any matter affecting the Report, which may come or be brought to AECOM’s attention after the date of the Report.

Certain statements made in the Report that are not historical facts may constitute estimates, projections or other forward-looking statements and even though they are based on reasonable assumptions as of the date of the Report, such forward-looking statements by their nature involve risks and uncertainties that could cause actual results to differ materially from the results predicted. AECOM specifically does not guarantee or warrant any estimate or projections contained in this Report.

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Neath Port Talbot – Sandfields School – BREEAM Ene04 LZC Feasibility Study Report


Contents

1 Executive Summary ............................................................................................................................................... 4

1.1 Baseline energy consumption, cost and GHG emissions 4 1.2 Impact of feasible LZCs 5 1.3 Recommendations 5

2 Introduction ............................................................................................................................................................ 8

2.1 Scope of work 8 2.2 Site information 9 2.3 Exclusions and clarifications 10

3 Baseline scenario ................................................................................................................................................ 11

3.1 Baseline building services 11

4 Shortlisting LZCs ................................................................................................................................................. 12 5 Solar Photovoltaics ............................................................................................................................................. 13

5.1 Introduction 13 5.2 Key considerations 13 5.3 System sizing and cost / benefit 14

5.3.1 Summary 14

6 Solar Thermal Hot Water ..................................................................................................................................... 15


6.3.1 Summary 16

7 Biomass Heating System .................................................................................................................................... 17


7.3.1 Summary 20

8 Ground Source Heat Pump (GSHP) .................................................................................................................... 21

8.1 Introduction 21 8.2 Key Considerations 22 8.3 System sizing and cost / benefit 22

8.3.1 Summary 23

9 Air Source Heat Pump (ASHP) ............................................................................................................................ 24

9.1 Introduction 24 9.2 Key Considerations 24 9.3 System sizing and cost / benefit 25

9.3.1 Summary 26

10 Summary .............................................................................................................................................................. 27

10.1 Overall conclusions and recommendation 29 10.2 Notes on costings 29

11 Appendix .............................................................................................................................................................. 30

11.1 Site information 30 11.2 Baseline energy consumption 30 11.3 Biomass (Wood Pellets) – System sizing and cost / benefit 31



1 Executive Summary

This report presents the findings of a low and zero carbon energy technologies (LZCs) desktop feasibility study carried out

by AECOM for the Sandfields secondary school by Seaway Parade, Port Talbot, SA12 7PA. The building is one of the two

proposed new schools by the Neath Port Talbot Council.

This study contributes towards the BREEAM 2014 Ene04 credit. This credit can only be achieved if a local LZC technology

is specified for the building / development in line with the recommendations of this feasibility study, and that this results in

a meaningful (typically at least 5%) reduction in regulated carbon dioxide equivalent (CO2e) emissions or energy use,

compared with the baseline energy demand. Depending on the impact of any installed LZCs there may be additional

credits available from Ene01. The final credit(s) awarded will be based on the as-built BRUKL document and as such

cannot be guaranteed until this document has been produced.

1.1 Baseline energy consumption, cost and GHG emissions

Design-stage calculations of the expected energy demands are based on the provided gross internal floor area (GIFA) in

the post-tender and are calculated using industry standard energy benchmarks1.

Following some analysis and calculations to allow for other known factors as described in the report, Table 1 shows the

expected energy demands for the buildings used in this study. The diagrams in Figure 1 demonstrate that although electric

utilities account for only 21% of total consumption, it makes up for just over half of the total consumption cost and 37% of

total emissions; therefore, the biggest improvements in cost and emissions can be made in the electric utility.

Table 1 – Summary of overall expected energy consumption, cost, and GHG emissions

Utility Consumption

(kWh p.a.) Cost (£ p.a.) GHG emissions (tCO2e p.a.)

Electricity 248,000 26,000 102

Gas (Total) 930,000 23,700 171

Gas (Hot water) 97,164 2,476 18

Gas (Space heating) 832,836 21,224 153

OVERALL TOTALS 1,178,000 49,700 273

Figure 2 – Utilities’ proportions of the overall energy consumption, cost, and GHG emissions

1 CIBSE TM46: 2008



1.2 Impact of feasible LZCs

A wide range of LZCs were initially considered; then a shortlist of potentially feasible LZCs were analysed in further detail

via calculations. Table 3 and the charts on the following pages show the potential impact of the shortlisted LZCs.

1.3 Recommendations

Based upon the indicative results provided within this report it is recommended that the use of solar photovoltaics is

considered further:

No significant constraints were identified to the deployment of solar photovoltaics;

Solar photovoltaics offer the greatest level of whole life cost / benefit of all the technologies;

Solar photovoltaics offer the highest level of greenhouse gas emission savings, relative to base case of gas

boilers;

Solar photovoltaics yield the quickest simple payback period, of approximately nine years

Solar photovoltaics would therefore be the recommended technology to achieve the targeted BREEAM 2014 Ene04 /

Ene01 credit(s), providing that all site constraints and other key considerations can be met or overcome.

The final credits awarded will need to be based on the as-built BRUKL document and as such cannot be guaranteed until

this document has been produced.



Table 3 – Summary of cost/benefit analysis of LZCs

No. LZC Feasible Sizing principleNet annual

revenue (£ p.a.)

Fuel Cost

saving (%)

GHG

emissions

saving

(tCO2e p.a.)

GHG saving

(%)CAPEX (£)

Simple

payback

(years)

Whole life

cost / benefit

(£ spent /

lifetime £

saved)

£ capex / annual

tCO2e saved (£/tCO2e

p.a.)

Recommended?

1Connection to district

heat network (DH)

No; A nearby network is proposed, but none is known to be currently

operating. Allowance for future connection to a district heating scheme

(space for PHX etc.) should be given.

-- -- -- -- -- -- -- -- -- --

2Combined heat &

power (CHP)

No; heat demand profiles inadequate for installation of CHP unit. Run

hours not expected to exceed 4,500hrs/annum required to achieve

commercial viability (Carbon Trust)

% of thermal energy to be met by

CHP, and typical CHP load factor.-- -- -- -- -- -- -- -- --

3Tri-generation (Tri-

gen)

No; localised cooling assumed on-site; too small to be viable for cooling

export. Likely capital costs excessive for the amount of cooling needed.-- -- -- -- -- -- -- -- -- --

4Solar photovoltaic

panels (PV)Yes; Could be installed on Sandfields building roof. % of available roof area. £27,252 54.8% 85.2 31.2% £233,300 8.6 £311,740 £2,700 YES

5Solar thermal hot

water (STHW)Yes; Could be installed on Sandfields building roof.

To provide 100% of HWS demand in

summer£20,090 40.4% 31.8 11.6% £222,700 11.1 £179,100 £7,000 NO

6 Wind turbines (WT)

No; As a general rule, a wind speed of less than 4.9 m/s is not

considered to be sufficient to make wind a viable energy source (Natural

Energy). The average wind speeds at the Sandfields school site (SA12

7PA) is 3.4 m/s at 10m agl (NOABL).

-- -- -- -- -- -- -- -- -- --

7Biomass boilers

(Biomass)Yes; assumed sufficient space in plantroom for plant / fuel store etc.


Biomass, and typical Biomass load

factor.

£7,417 31.3% 64.8 23.7% £111,922 13.0 -£661 £1,727 NO

8Air source heat pump

(ASHP)

Yes; It is assumed that there is sufficient space for an ASHP externally or

in the plant room.

Multiples of 58kW ASHP units from

Daikin to provide 75-90% of space

heating demand

£948 1.9% 1.8 0.7% £171,645 Never -£157,429 £93,235 NO

9Ground source heat

pump (GSHP)

Yes; It is assumed that there is sufficient space for a GSHP externally or

in the plant room.200kW £16,908 34.0% 0.95 0.3% £224,769 12 £44,417

Greater than

£100,000NO

10Water source heat

pump (WSHP)No; No existing suitable waterway nearby. -- -- -- -- -- -- -- -- -- --

11Hydroelectric

generation (Hydro)No; No existing suitable waterway nearby. -- -- -- -- -- -- -- -- -- --



0.0% 0.0% 0.0%

31.2%

11.6%

0.0%

23.7%

0.7% 0.3% 0.0% 0.0%0%

5%

10%

15%

20%

25%

30%

35%

DH CHP Tri-gen PV STHW WT Biomass ASHP GSHP WSHP Hydro

%

GHG emissions saving as % of baseline

0 0 0

8.6

11.1

0

13.0

£0

12

0 0 0

2

4

6

8

10

12

14


ye

ars

Simple payback

£0 £0 £0

£2,700

£7,000

£0

£1,727£236,453 £0 £0

£0

£1,000

£2,000

£3,000

£4,000

£5,000

£6,000

£7,000

£8,000


£/t

CO

2e

p.a

.

£ capex / annual emissions saved

£236,453

£93,235

£0 £0 £0

£311,740

£179,100

£0

-£661

-£157,429

£44,417£0 £0

-£200,000

-£100,000

£0

£100,000

£200,000

£300,000

£400,000

(£ s

pe

nt

/ li

feti

me

£ s

ave

d)

Whole life cost / benefit



2 Introduction

This report presents the findings of a low and/or zero carbon energy technologies (LZCs) desktop feasibility study carried

out by AECOM for the Sandfields Secondary School at Baglan Bay, Neath Port Talbot.

The project is a new secondary school building which will house a mixture of general teaching classrooms, design and

technology classrooms, science laboratories, rooms for the arts, an auditorium and a large sports hall. Due to this LZC

study being carried out at a very early stage of planning, there are no M&E services strategy reports available and

therefore there is no information on the Mechanical, Electrical and Public Health Service Systems. However, it has been

assumed from a discussion between the MEP team that heating throughout the school will be provided by underfloor

heating.

This study contributes towards the BREEAM 2014 credit available for part of Ene042 for the project. This credit can only be

achieved if a local LZC technology is specified for the building / development in line with the recommendations of this

feasibility study, and that this results in a meaningful (typically at least 5%) reduction in regulated carbon dioxide

equivalent (CO2e) greenhouse gas emissions or energy use, compared with the baseline energy demand. Depending on

the impact of any installed LZCs there may be additional credits available from Ene01. The final credit(s) awarded will be

based on the as-built BRUKL document and as such cannot be guaranteed until this document has been produced.

The study is based on the estimated load requirements of the building (baseline energy demand) and engineering

calculations for relevant LZCs. The study was conducted by individuals who have acquired substantial expertise or a

recognised qualification for undertaking assessments, designs and installations of low or zero carbon solutions in the

commercial buildings sector and who are not professionally connected to a single low or zero carbon technology or

manufacturer.

This report contains rounded numbers for ease of reading and in line with limitations of accuracy. Sometimes the

rounding produces small (negligible) differences between different tables, which should be ignored.

2.1 Scope of work

This report has been structured in accordance with the requirements and guidance of BREEAM 2014 Ene04, to provide an

investigation into the viability of eligible LZC energy sources for the proposed development.

Initially an estimated baseline energy demand, energy cost, and regulated greenhouse gas (GHG) carbon dioxide

equivalent (CO2e) emissions will be calculated for the relevant part(s) of the proposed development. Then the energy and

cost impact of potentially suitable LZCs will be evaluated against this baseline.

The following LZCs will be considered:

1. Connection to district heat network (DH)

2. Combined heat and power (CHP)

3. Tri-generation (Tri-gen)

4. Solar photovoltaic panels (PV)

5. Solar thermal hot water (STHW)

6. Wind turbines (WT)

7. Biomass boilers (Biomass)

8. Air source heat pump (ASHP)

9. Ground source heat pump (GSHP)

10. Water source heat pump (WSHP)

11. Hydroelectric generation (Hydro)

After an initial consideration of basic constraints, a shortlist of potentially feasible LZCs will be created. The remaining

LZCs which are deemed unfeasible at this stage will not be considered further. For each of the shortlisted LZCs the

following issues will be addressed in further detail:

Introduction

Site / land use

Local planning

Noise / vibration impact

Feasibility of exporting heat / electricity

Incentives & grants

System sizing and cost / benefit

Finally, a recommendation will be made based on the results of the analysis.

2 BREEAM UK Refurbishment and Fit-out 2014 - Technical Manual

http://www.breeam.com/ndrefurb2014manual/#06_energy/ene04.htm%3FTocPath%3D6.0%2520Energy%7C_____4



2.2 Site information

The Sandfields Secondary School is by the Seaway Parade, which is situated in Neath Port Talbot, just south of the new

school, Ysgol Bae Baglan, as indicated in Figure 2 below. The school is a two level building meant to serve approximately

650 students aged 11-16. Majority of the school classrooms are dedicated to general teaching, but also includes spaces

especially for the arts (art, music, drama), design and technology, maths/IT, and science (e.g. laboratories). Additionally,

the school has a large sports hall, a main hall/auditorium, and an activity/dance studio. At this early concept design stage,

it has been assumed that underfloor heating is applied throughout the school building.

Figure 2 – Site plan

Table 4 - Site information

Site information

Building name Sandfields Secondary School

Address Seaway Parade, Neath Port Talbot

Location type Town - urban

Primary function(s) General Teaching

Approx. heated floor area (m2) 6,200

Table 5 – Overview of key building services

Overview of key proposed building services systems

Primary heating system LTHW gas-fired condensing boilers on ground floor

Space heating emitters Underfloor heating

Space cooling TBC (likely to have local VRF to I.T. and Server Rooms)

Hot water Gas fired water heaters

Ventilation Primarily naturally ventilated

Lighting Modern LED system

Key constants used in the study are shown in Table 6 – Key constants used in this study. The unit charges are based on

design-stage assumptions of the electricity and gas demands, and have been taken from quarterly prices of fuels

purchased for non-domestic customers from the Department of Energy & Climate Change.

Sandfields School

Ysgol Bae Baglan



Table 6 – Key constants used in this study

2.3 Exclusions and clarifications

The following exclusions and clarifications apply to the study:

The study was primarily desktop-based.

The majority of site information was based on the post-tender received and calculations.

Energy consumptions were based on CIBSE Energy Benchmarks.

The LZCs have been assessed based on the data provided and engineering principles.

No design work has been undertaken for the various LZCs – instead this study only provides an initial indication

of the potential viability and possible impact.

Capital costs are indicative only based on recent projects, published guidance, etc. but have not been reviewed

by a quantity surveyor. All costs exclude VAT, and do not allow for any main contractor overheads, prelims or

profit, nor do they include any contingency.

Energy & emissions costs

Item Value Units Source

Electricity (normal) 10.47 p/kWh Table 3.4.1

Electricity export 4.85 p/kWh OFGEM latest tariff levels

Gas 2.549 p/kWh Table 3.4.1

Carbon Reduction Commitment (CRC) 16.1 £ / tCO2e Gov.uk cost allowance with year 16/17

Emission factors


Electricity 0.41205 kgCO2e/kWh GHG Conversion Factors (UK Gov)

Gas 0.18400 kgCO2e/kWh GHG Conversion Factors (UK Gov)

Wood Chips 0.01600 kgCO2e/kWh SAP 2012 table 12

Wood Pellets 0.03900 kgCO2e/kWh SAP 2012 table 12

Heating systems


Boilers seasonal efficiency 88.2% % M&E design team / tech. spec.



3 Baseline scenario

The expected energy demand (baseline energy demand) of the building was calculated through the use of energy

benchmarks. The gross internal floor area (GIFA) of Sandfields School was confirmed as 6200m2. The benchmark

category of “Schools and Seasonal Public Buildings” was applied to the entire GIFA to derive an energy demand for the

proposed development. The total baseline energy demand of the building is calculated to be circa 1,178,000 kWh p.a.

Table 7 – Summary of overall energy consumption, cost, and GHG emissions

Utility Consumption

(kWh p.a.) Cost (£ p.a.) GHG emissions (tCO2e p.a.)

Electricity 248,000 26,000 102

Gas (Total) 930,000 23,700 171

Gas (Hot water) 97,164 2,476 18

Gas (Space

heating) 832,836 21,224 153

OVERALL

TOTALS 1,178,000 49,700 273

3.1 Baseline building services

Table 8 – Key parameters of proposed building services


LTHW flow/return temperatures

40 / 30 °C Advised by M&E design team

Boilers seasonal efficiency 88.2% % Referred to current industry standards based on previous AECOM energy models

Peak space heating demand 627 kWth Advised by M&E design team

Peak hot water demand 73 kWth Advised by M&E design team

Electricity will be supplied and metered at low voltage, so there are no transformer losses to account for on-site.

Figure 3 – Utilities’ proportions of the overall expected energy consumption and cost

From the above charts, electricity is only 21% of the power consumption but accounts for 52% of the total consumption cost. To minimise this electricity cost, renewable energies that create electricity such as Solar Photovoltaics or Combined Heat and Power (CHP) would be beneficial. However, further calculations will show us the most cost effective and emission saving technology.



4 Shortlisting LZCs

The following table provides reasoning for the shortlisted LZCs to be investigated further in this study.

Table 9 – Reasoning for shortlisting of LZCs

No. LZC Feasible Additional notes


heat network (DH)

No; A nearby network is proposed, but none

is known to be currently operating. Allowance

for future connection to a district heating

scheme (space for PHX etc.) should be

given.

--

2Combined heat &

power (CHP)

No; heat demand profiles inadequate for

installation of CHP unit. Run hours not

expected to exceed 4,500hrs/annum required

to achieve commercial viability (Carbon

Trust)

--

3 Tri-generation (Tri-gen)

No; localised cooling assumed on-site; too

small to be viable for cooling export. Likely

capital costs excessive for the amount of

cooling needed.

--

4Solar photovoltaic

panels (PV)

Yes; Could be installed on Sandfields

building roof.Competes with STHW for roof space

5Solar thermal hot water

(STHW)

Yes; Could be installed on Sandfields

building roof.Competes with PV for roof space


No; As a general rule, a wind speed of less

than 4.9 m/s is not considered to be

sufficient to make wind a viable energy

source (Natural Energy). The average wind

speeds at the Sandfields school site (SA12


--

7Biomass boilers

(Biomass)

Yes; assumed sufficient space in plantroom

for plant / fuel store etc.--


(ASHP)

Yes; It is assumed that there is sufficient

space for an ASHP externally or in the plant

room.

Building is assumed to be heated entirely

through underfloor heating. The ASHP would

then provide heat to the underfloor heating

system.

9Ground source heat

pump (GSHP)

Yes; It is assumed that there is sufficient

space for a GSHP externally or in the plant

room.

GSHP could provide heat to the underfloor

heating system of the building.

10Water source heat

pump (WSHP)No; No existing suitable waterway nearby. --

11Hydroelectric

generation (Hydro)No; No existing suitable waterway nearby. --



5 Solar Photovoltaics

5.1 Introduction

Solar photovoltaic (PV) systems convert energy from the sun into direct current (DC) electricity through the use of semi-

conductor cells connected together and mounted into modules. Modules are connected to an inverter that converts DC

into alternating current (AC), enabling integration with the normal grid supply. If the output of a PV system exceeds the

building demand at any time, the surplus electricity can then be exported to the grid.

PV technologies can be categorised into monocrystalline, polycrystalline and amorphous silicon (thin film) systems.

Monocrystalline cells are the most efficient, with a conversion efficiency of 15-20% (the fraction of incident solar energy

that is converted into electricity). Amorphous silicon is the least efficient (6-8%). Installed costs of these technologies are

commensurate with their performance, and monocrystalline is the most expensive of the three. A fourth variety, hybrid,

utilises both thin film and polycrystalline silicon to improve performance.

Various options exist, most normally being fixed to sloping or flat roofs; but also can be incorporated into building facades,

glass roof structures and solar shading devices (often at much greater cost). Careful consideration of the building’s design

features and the budgetary concerns of the development are required when deciding which type of installation might be

the most appropriate.

PV modules can also be equipped with tracking systems, which allow the modules to follow the course of the sun. This

can potentially increase electricity production compared with modules at a fixed azimuth and inclination, but can be an

expensive addition, usually reserved for larger scale installations.

This section considers the potential cost / benefit of a standard roof-mounted monocrystalline PV installation.

5.2 Key considerations

No. Item Details

1 Site / land use

The Sandfields building has four main large roof spaces, each pitched at 3 degrees. The

roof above the Sports Hall roof and Boiler Room & Kitchen sections would be most suitable

for the PV Panels because those parts are south facing. The PV would be mounted on tilted

stands fixed to the roof structure, and oriented facing south. From current drawings, there is

no area allocated to equipment, therefore it is assumed that the whole roof area will be

available.

2Local

planning

No local planning constraints have been identified that would prohibit the use of a PV

system here, however this should be confirmed if this option is pursued.

3

Noise /

vibration

impact

There are no noise or vibration impacts associated with the operation of PV. The only

components which produce noise are the inverters, and it is typically comparable to that

generated by a desktop PC.

4

Feasibility of

exporting heat

/ electricity

It is unlikely that the building electricity demand would fall below the output of a PV system

at this site during daytimes (ie. when the system could be generating). Nevertheless, it is

feasible that electricity could be exported should the situation arise.

5Incentives &

grants

The latest applicable feed-in-tariff rates have been incorporated into our cost / benefit

calculations.



5.3 System sizing and cost / benefit

The roof area of the Sandfields building is assumed to be the same as the ground floor area despite the 3° inclines of the

roofs. However, the floor areas of each room were not included in the floor plans provided in the post-tender. Since the

sports and main halls are two stories high, the roof area is assumed to be half of the total floor area excluding the halls,

plus the floor areas of the halls themselves.

5.3.1 Summary

On the basis of these calculations, solar PV could achieve approx. 32% reduction on regulated baseline GHG emissions,

with a payback period of 8.6 years. Assuming a lifetime of 20 years the lifetime profit would be £311,740; however there is

a large capital cost of £233,300. If the capital cost is too large then a small initial amount of panels could be bought, and

then increased as funds became available. A smaller PV system could be installed in combination with a STHW system,

but given the difference in cost / benefit we have worked on the basis that this would not be pursued.

Energy & system parameters

No. Item Value Units Source

1 Total available roof area 3,500 m2 Approximated from drawings and GIFA of 6200

specified in Post Tender

2 PV panels coverage factor 40% % 40-60% typical coverage for flat roof

3 Area of active PV 1,400 m2 [1] x [2]

4 PV active area per unit output 6.6 m2/kWp Advised by solar installer

5 PV system peak output 212.1 kWp [3] ÷ [4]

6 PVGIS annual electricity generation 206,818 kWh p.a. [7] x [5]

7 PVGIS annual generation per kWp 975 kWh p.a. / kWp PVGIS Map

8 Expected electricity export 0 kWh p.a. PV kWp is lower than expected daytime demand

GHG emissions impact

9 Electricity GHG emission factor 0.41205 kgCO2e/kWh GHG Conversion Factors (UK Gov)

10 Annual GHG emissions saving 85.2 tCO2e p.a. ([6] x [9]) ÷ 1000

11 CRC cost of allowances £16.10 £/tCO2e Gov.uk cost allowance with year 16/17

12 Annual CRC saving £1,372 £ p.a. [10] x [11]

OPEX & revenue

13 Electricity average unit charge 10.47 p/kWh Table 3.4.1

14 Value of generated electricity £21,650 £ p.a. [6] x [13] ÷ 100

15 Electricity export rate 4.85 p/kWh OFGEM latest tariff levels

16 Value of exported electricity £0 £ p.a. [8] x [15] ÷ 100

17 Expected feed-in tariff rate 2.70 p/kWh OFGEM latest tariff, 50-250 kWp higher rate

18 Value of feed-in tariff £5,580 £ p.a. [6] x [17] ÷ 100

19 Estimated annual maintenance cost £1,350 £ 1 day for contractor + materials

20 Net annual revenue £27,252 £ p.a. [14] + [16] + [18] + [12] - [19]

CAPEX

21 PV installed cost per kWp £1,100 £ / kWp Average of recent quotes for similar system sizes

22 Estimated PV system capital cost £233,300 £ [5] x [21]

Payback & life-cycle cost effectiveness ratio

23 Simple payback period 8.6 years [22] ÷ [20]

24 Lifetime of system 20 years Duration of feed-in-tariff payments

25 Lifetime net revenue £545,040 £ [20] x [24]

26 Whole life cost / benefit £311,740 £ [25] - [22]

27 £ capex / annual tCO2e saved £2,700 £/tCO2e [22] ÷ [10]

No. LZC

Net annual

revenue (£

p.a.)

Cost

saving

(%)

GHG emissions

saving (tCO2e

p.a.)

GHG

saving

(%)

CAPEX (£)

Simple

payback

(years)

Whole life cost /

benefit (£ spent /

lifetime £ saved)

£ capex / annual

tCO2e saved

(£/tCO2e p.a.)

4Solar photovoltaic

panels (PV)£27,252 54.8% 85.2 31.2% £233,300 8.6 £311,740 £2,700



6 Solar Thermal Hot Water

6.1 Introduction

Solar thermal hot water (STHW) systems convert energy from the sun into heat for domestic hot water. Solar thermal

collectors are typically connected to a circulating closed loop of fluid (normally water or glycol mix) which is used to raise

the temperature of a hot water cylinder via a heating coil. Normally the hot water cylinder also contains a LPHW heating

coil connected to the main building heating system to provide top-up as necessary. Alternatively a separate STHW hot

water tank can be installed to pre-heat incoming water for a main indirect LPHW-fed or direct gas-fired HWS storage tank.

STHW collectors are normally either ‘flat plate’ or ‘evacuated tube’ type. Evacuated tube are more efficient at converting solar radiation into useful heat, however are more costly. CIBSE Knowledge Series guide 15 advises a typical energy output of around 400 kWhth p.a. per m

2 of active solar thermal collector area, understood to be for flat-plate collectors.

Domestic systems are generally sized to give a reasonably high ‘solar fraction’ (the fraction of annual hot water demand

which is supplied by the solar thermal system). However, for a non-domestic installation since the hot water demand is

usually larger, a high solar fraction would often require an unfeasible number of solar thermal collectors to be installed.

Instead for a non-domestic installation the solar fraction can be used to dictate an amount of roof area / solar collector

area which is considered reasonable for the site.

STHW collectors can be fixed to pitched or flat roofs. Avoiding over-shading is important but not as important as in PV

design. Other considerations include ensuring adequate access and locations for pipe-runs, location of circulation pump

equipment, expansion vessels, and hot water cylinders if required. Also, if there is no hot water demand for a period in the

summer, the system design needs to be able to deal with an overheating risk and prevent possible boiling of the working

fluid. This can be achieved via a number of methods including ‘draindown’ and/or expansion vessels.

This section considers the potential cost / benefit of a standard roof-mounted flat-plate STHW installation.


No. Item Details

1 Site / land use

The Sandfields building has pitched roofs which may be most suitable for STHW, which would be mounted on tilted stands, typically fixed to the roof structure. The cost / benefit calculations below indicate the maximum possible size taking into account relevant constraints and considerations such as access, maintenance, over-shading, etc. Could be installed alongside a PV system, however the PV system active area would be reduced in that case.

2 Local planning

No local planning constraints have been identified that would prohibit the use of a STHW system here, however this should be confirmed if this option is pursued.

3 Noise / vibration impact

There are no noise or vibration impacts associated with the operation of STHW. The only components which produce noise would be the circulation pump and it is typically located in a plant room or back of house area.

4

Feasibility of exporting heat / electricity

Exporting heat from a normal STHW system is not viable due to the relatively low amount of energy generated, and the likely high cost of installing heat export infrastructure.

5 Incentives & grants

The latest applicable renewable heat incentive tariff rates have been incorporated into our cost / benefit calculations.




6.3.1 Summary

The simple payback of the calculated STHW is one of the longest at just over 11 years. Additionally, the CAPEX for the

proposed system size is also one of the greatest. The expected GHG emissions impact is just less than that of Combined

Heat and Power, yielding a small saving of 11.6%. The large CAPEX, long payback, and relatively small GHG savings,

makes STHW an unattractive LZC solution. As mentioned in the PV section summary, a combination of a PV system and

STHW system is not pursued due to the difference in cost / benefit.

Energy & system parameters


1 Expected daily hot water demand 10,550 litres / day CIBSE Guide A: Table 6.2.; BSRIA: RoT - Table 22

2 STHW output per unit panel active area 45 litres / m2 Typical for flat-plate collectors *

3 Active solar thermal collector area 234 m2 [1] ÷ [2]

4 Active area % of gross panel area 90% m2 Typical for flat-plate collectors

5 Gross STHW collector area 260 m2 [3] ÷ [4]

6 Total available roof area 3,500 m2 Approx. from drawings

7 STHW collectors % of total roof 7% % [5] ÷ [6]

8 Selected gross STHW collector area 260 m2 Revised after comparison with available roof area

9 Annual solar insolation 1,300 kWh / m2 PVGIS map

10 Collector to solar store efficiency 50% % Typical for STHW allowing for losses

11 Annual solar thermal collector output 152,400 kWhth p.a. [8] x [4] x [9] x [10]

12 Boilers seasonal efficiency 88.2% % M&E design team / tech. spec.

13 Annual gas saving 172,800 kWh p.a. [11] ÷ [12]

GHG emissions impact

14 Gas GHG emission factor 0.1840 kgCO2e/kWh GHG Conversion Factors (UK Gov)

15 Annual GHG emissions saving 31.8 tCO2e/kWh ([13] x [14]) ÷ 1000

16 CRC cost of allowances £16.10 £/tCO2e Gov.uk cost allowance with year 16/17

17 Annual CRC saving £512 £ p.a. [15] x [16]

OPEX & revenue

18 Gas unit charge 2.55 p/kWh Table 3.4.1

19 Value of avoided gas £4,405 £ p.a. [13] x [18] ÷ 100

20 Expected renewable heat incentive rate 10.28 p/kWh OFGEM latest tariff

21 Value of renewable heat incentive £15,670 £ p.a. [11] x [20] ÷ 100

22 Estimated annual maintenance cost £500 £ 1 day for contractor + materials

23 Net annual revenue £20,090 £ p.a. [19] + [21] + [17] - [22]

CAPEX

24 STHW installed cost per m2 active £950 £ / m

2 Typical cost incl. all components (CIBSE KS15)

25 Estimated STHW system capital cost £222,700 £ [8] x [4] x [24]

Payback & life-cycle cost effectiveness ratio

26 Simple payback period 11.1 years [25] ÷ [23]

27 Lifetime of system 20 years Typical for gas-fired CHP

28 Lifetime net revenue £401,800 £ [23] x [27]


30 £ capex / annual tCO2e saved £7,000 £/tCO2e [25] ÷ [15]

* Average summer 5 peak sunshine hours/day x 1 kWth/m2, 50% eff iciency for STHW collectors to solar store, 50°C w ater temperature uplif t.

No. LZC

Net annual

revenue (£

p.a.)

Cost

saving

(%)

GHG emissions

saving (tCO2e

p.a.)

GHG

saving

(%)

CAPEX

(£)

Simple

payback

(years)

Whole life cost /

benefit (£ spent /

lifetime £ saved)

£ capex / annual

tCO2e saved

(£/tCO2e p.a.)

5Solar thermal hot

water (STHW)£20,090 40.4% 31.8 11.6% £222,700 11.1 £179,100 £7,000



7 Biomass Heating System

7.1 Introduction

Biomass is normally considered a carbon neutral fuel, as the carbon dioxide emitted during burning has been (relatively)

recently absorbed from the atmosphere by photosynthesis and no fossil fuel is involved. However this report takes into

account the carbon emissions associated with the sourcing, processing and transportation of the biomass; a CO2 emission

factor of 0.039kgCO2/kWh3

has therefore been assumed for wood pellets, and 0.016kgCO2/kWh3 for wood chip.

Wood from forests, urban tree pruning, farmed coppices or farm and factory waste can be burnt directly to provide heat in

buildings. Most of these wood sources are commercially available in the form of wood chips or pellets, which makes

transport and handling on site easier.

Biomass pellets are denser and have a higher calorific value than biomass woodchips15 and as such a smaller fuel store

can be designed to serve the same heat demand if wood pellets are chosen. However, the benefit of woodchip fuel is that

although it is bulkier, less efficient to burn and potentially more problematic than pellets, its price per unit energy of heat

generated is typically less than that of biomass pellets.

Systems are typically fed automatically by screw-drives from fuel hoppers and incorporate gas firing and automatic de-

ashing. Systems are also designed to burn without emitting smoke in order to comply with the Clean Air Act.

Unlike solar and wind renewable energy sources, biomass fuel is not abundant and free. When comparing costs, wood

chips and pellets are becoming progressively more competitive compared to increasing gas prices. However, biomass

prices are known to fluctuate due to various market forces.

The most common application of biomass heating is one or more boilers in a sequenced (multi-boiler) installation that

includes an alternative fuel boiler (such as a gas boiler), to provide security of heat supply.


No. Item Details

1 Site / land use

The boiler room is assumed to be sufficient to accommodate the Biomass boiler and associated equipment. In addition to the boiler, space is also required for fuel storage. Biomass boilers are unable to quickly adjust their output to match current demand, hence biomass heating systems often incorporate a thermal store. The thermal store acts as a buffer to more successfully react to immediate changes in heat demand. Consideration should be given to the size and location of any thermal store and other associated equipment required. The site access would determine the limitation of the fuel delivery truck’s size.

2 Local planning

No local planning constraints have been identified that would prohibit the use of a Biomass boiler system here, however this should be confirmed if this option is pursued. Emissions from the biomass installation need to be monitored and controlled in order to reduce particle emissions and to meet any local constraints.


There are no noise or vibration impacts associated with the operation of Biomass installations. The only components which produce noise would be the circulation pump and it is typically located in a plant room or back of house area.

4 Feasibility of exporting heat / electricity

Exporting heat from a normal Biomass system is not viable due to the relatively low amount of energy generated, and the likely high cost of installing heat export infrastructure.

5 Incentives & grants The latest applicable renewable heat incentive tariff rates have been incorporated into our cost / benefit calculations.

3 Standard Assessment Procedure 2012 – Table 12




Sizing a biomass boiler


1 Rated Output [kW] 200 kW

2 Modulation 30% % Rule of thumb for Biomass systems

3 Minimum Output [kW] 60.0 kW [1] x [2]

RequiredEnergy of Biomass

4 SH & DHW Demand 930,000 kWh Baseline figue

5 Demand Met by System 465000 kWh [4] x 50%

6 Boiler Size 200 kW [1]

7 Efficiency of Boiler 80% % Typical for Biomass systems

8 Required Energy Delivered 581,250 kWh [5] ÷ [7]

Required Energy of Gas

9 Demand Met by System 465,000 kWh [4] - [5]

10 Boiler Size 700 kW See Baseline

11 Efficiency of Boiler 88.2% % See Constants

12 Required Energy Delivered 527,210.88 kWh [9] ÷ [11]

Fuel Required (Wood Chips)

13 Calorific Value 3.7 kWh/kg CIBSE KS10 Table 1

14 Fuel Required 157,094.59 kg [8] ÷ [13]

Sizing Fuel Store (Wood Chips)

15 Sized Peak Heat Load 200 kW [1]

16 Operating Hours 100 hours CIBSE Guide B section 1.6.3.4

17 Efficiency 80% % [7]


19 Density 200 kg/m³ CIBSE KS10 Table 1

20 Volume 33.8 m³ ([15]x[16])/[17]/[18]/[19]

Emissions Generated by Biomass Heating System

Gas

21 Emission Factor 0.184 kgCO₂/kWh See constants

22 Emissions Generated 97,005 kgCO₂ [12]x[21]

Wood Chips

23 Emission Factor 0.016 kgCO₂/kWh SAP 2012 Table 12


25 Total Emissions Generated 106,305 kgCO₂ [22]+[24]

Emissions Saved by Biomass

26 Base Scenario Emissions 171,117 kgCO₂ Baseline calculations

27 Emissions Saved 64,811.916 kgCO₂ [26]-[25]

28 Total Emissions 273,305.441 kgCO₂ Baseline calculations

29 Percentage Reduction 23.714% % [27]/[28]

30 CRC cost of allowances 16.1 £ / tCO2e Gov.uk cost allowance with year 16/17

31 Annual CRC saving 1043 £ p.a. [27]x[30]

Installation Cost

No. Part Price £ Source

32 Biomass boiler w/ ancillaries 50,132.50 £ scaled from previous quote

33 Biomass - buffer [litres] 10,000.00 £ £1 per litre, volume = 50 x rated output

34 Biomass - fuel store [m3] 36,220.05 £ scaled from previous quote

35 Gas boiler 700kW 15,569.18 £ See Constants

36 Total 111,921.73 £ [32]+[33]+[34]+[35]



Individual Fuel Cost

Gas

37 Cost £0.03 £/kWh

38 Annual Fuel Cost 13,443.88 £ [12]x[37]

Wood Chips

39 Cost £0.03 £/kWh Biomass Energy Centre


Renewable Heat Incentive


42 RHI Tier 1 1,314 Hours 8760 x 15%

43 Tier 1 kWh 262,800 kWh [41]x[42]

44 Tier 2 kWh 202,200 kWh [5]-[43]

45 Tier 1 Tariff 0.0524 £/kWh OFGEM


47 Tier 1 Revenue 13,770.72 £ [43]x[45]

48 Tier 2 Revenue 4,589.94 £ [44]x[46]

49 Annual RHI Revenue 18,360.66 £ [47]+[48]

Annual Cost of System

50 Maintenance Cost [Biomass] 4,400.00 £ AEA for DECC review

51 Maintenance Cost [Gas] £1,750.00 £

52 Total Cost 18,034.12 £ [38]+[40]+[50]+[51]-[49]-[31]

Base Scenerio Annual Cost (Gas Boiler Only)

53 Base Scenario Heating Cost 23,700.00 £ Baseline calculations

54 Maintenance Cost 1,751.50 £

55 Total Cost 25,451.50 £ [53]+[54]

Pay Back & life-cycle cost effectiveness ratio

56 Biomass Installation Cost 111,921.73 £ [36]

57 Base Scenario Cost 15,569.18 £ Cost of 700kW boiler

58 Simple Payback Cost 96,352.55 £ [56]-[57]

59 Annual Saving £7,417.38 £ [55]-[52]

60 Simple Payback [Years] 13.0 Years [58]÷[59]

61 Lifetime of system 15 Typical for Biomass systems

62 Lifetime of net saving 111,260.69 £ [59]x[61]

63 Whole life cost / benefit -661.04 £ [62]-[56]

64 £CAPEX / annual tCO2e saved £1,726.87 £ [56]÷([27]/1000)



7.3.1 Summary

Biomass systems using a wood pellet boiler and a wood chip boiler are compared to determine which system is more

advantageous. The simple payback period of the wood pellet biomass system is greater than its lifetime, whereas the

wood chip system has a simple payback of 13 years. The wood chip biomass boiler also outperforms the wood pellet

boiler in GHG emissions savings. Therefore the calculations of the wood chip biomass system are used to compare with

the other proposed LZC technologies. The GHG savings of the biomass system is the greatest of the proposed LZC

technologies, with a 23.7% reduction on baseline GHG emissions.

The operation and maintenance of biomass systems are more involved than the other considered LZC technologies.

Biomass systems require refuelling, which would involve fuel delivery and site access for the delivery truck; and feeding,

either by an automated process or manually by a caretaker. The quality of the fuel needs to be of a controlled standard,

otherwise the performance of the boiler may be reduced and damage may occur to the boiler or people. The year-round

availability of fuel is also crucial to the operation of biomass systems. Additionally, biomass systems and their flues require

regular servicing and maintenance in order to maintain the systems’ performance and efficiency. Any issues with one of

these criteria would hamper the feasibility of a biomass system; therefore a more detailed analysis of a biomass system on

site would be necessary if this technology is selected.

LZC

Net annual

revenue

(£ p.a.)

Cost

saving (%)

GHG

emissions

saving

(tCO2e p.a.)

GHG

saving (%)CAPEX (£)

Simple

payback

(years)

Whole life cost /

benefit (£ spent /

lifetime £ saved)

£ capex / annual

tCO2e saved

(£/tCO2e p.a.)

Wood

Chips£7,417 31.30% 65 23.7% 111,922£ 13 -£661 £1,727

Wood

Pellets£1,844 7.78% 51 18.8% 84,475£ Never -£56,816 £1,642



8 Ground Source Heat Pump (GSHP)

8.1 Introduction

Ground source heat pump [GSHP] systems consist of three main components namely:

A ground loop, which extracts heat from the ground via a network of buried pipes, installed either in vertical

boreholes or horizontal trenches. Pipes contain a working fluid which is a mixture of water and antifreeze, and is

circulated using a pump.

The heat pump unit itself, which uses a refrigerant to extract heat from the ground loop working fluid, via a heat

exchanger [the “evaporator”]. A compressor then raises the refrigerant to the required delivery temperature

[typically 30 to 50 C]; this heat is delivered into the distribution system via another heat exchanger [the

“condenser”].

The distribution system. This is the means by which heat is distributed around a building to provide space and

water heating. For heating, this can be under-floor heating, low temperature radiators or warm air.

In heating mode, the heat exchange fluid is pumped from the ground loop at 8-16°C and passes through the heat

exchange unit. Within the heat exchanger, the refrigerant expands and changes from liquid into gas. This absorbs heat

[latent heat of vaporization] from the fluid in the ground loop. Meanwhile the refrigerant is pumped to the compressor

where it is pressurized and superheated. This 'hot gas' releases the heat in the second ”sink‟ loop and warms the water in

the calorifier. As the refrigerant gas loses heat to the water in the calorifier, it condenses back into a liquid. The external

loop again provides the heat necessary to change the refrigerant back into a gas and the process is repeated. In cooling

mode, the same cycle is effectively reversed.

Heat pumps are especially well matched to under floor heating systems which do not require high temperatures. Using

large surfaces such as floors, as opposed to radiators, allows for a lower temperature heat transfer fluid. GSHPs use one

of the following types of external loop:

Open loop

Closed vertical loop

Closed horizontal loop

In an open loop system the thermal transfer fluid [water] does not return and is a 'once through' type system. This system

draws water from a well or lake, passes it through a heat exchanger in the building, and then discharges it. The site

contains no natural water resources that could be considered for this purpose, therefore open loop systems shall not be

considered further in this study.

A closed loop system, the most common, circulates the fluid through the loop field pipes. In a closed loop system there is

no direct interaction between the fluid and the earth; only heat transfer across the pipe.

A vertical closed loop field is composed of pipes that run vertically in the ground. A hole is bored in the ground, typically,

50-150m deep. Pipe pairs in the hole are joined with a U-shaped cross connector at the bottom of the hole. Vertical loop

fields are typically used when there is a limited area of land available.

Horizontal collectors are pipes buried in trenches in the ground, typically 0.5-2m deep; at this depth the ground

temperature fluctuates more significantly throughout the year, affecting the seasonal Coefficient of Performance [CoP] of

the system. The main thermal recharge for all horizontal systems in heating-only mode is provided for mainly by the solar

radiation to the earth’s surface. It is important not to cover the surface above the ground collector. The advantage of this

type of system is the simplicity of installation, but a larger area is required – approximately double the floor area that is to

be heated by the GSHP.

Due to the reduced output efficiencies of horizontal collectors, only a vertical borehole installation will be investigated

further in this report.



8.2 Key Considerations


No. Item Details

1 Site / land use

It is assumed the plant room will be sufficiently large to house the GSHP plant also the top

up gas boiler. It has also been assumed that bore holes required for the heat extraction

pipes will be created before the creation of the sports pitches. If taken further, it is

recommended that a thorough geological survey of the area be undertaken to establish the

suitability of a GSHP on the site. GSHP typically are only used in applications where the

flow/return temperatures are 40/30°C and as such are well suited for an under floor heating

system or oversized radiators.

2 Local planningNo local planning constraints have been identified that would prohibit the use of a GSHP

system here; however this should be confirmed if this option is pursued.

3Noise / vibration

impact

There are no noise or vibration impacts associated with the operation of GSHP. The only

components which produce noise would be the circulation pump and it is typically located in

a plant room or back of house area.

4

Feasibility of

exporting heat /

electricity

Exporting heat from a normal GSHP system is not viable due to the relatively low amount of

energy generated, and the likely high cost of installing heat export infrastructure.

5Incentives &

grants

The latest applicable renewable heat incentive tariff rates have been incorporated into our

cost / benefit calculations.

Baseload Energy


1 Heating Demand 734,561 kWh SH Consumption x Boiler Efficiency

2 Size of GSHP 200 kW Assumed size of system

3 Size of Top Up Gas Boiler 700 kW See Baseline

4 Size of Base Scenario Boiler 700 kW See Baseline

5 Demand met by GSHP 367,281 kWh [1] x 50% (assumed provision of GSHP)

6 Demand met by Gas Top Up 367,281 kWh [1]-[5]

Boreholes

7 Heat Extraction Rate 30 W/m

8 Length Required 6,667 m [2] x [7]

9 Depth of Borehole 80 m

10 Number of Boreholes 84.00 - [8] ÷ [9]

Annual energy used by GSHP

11 CoP 2 - Typical CoP for GSHP system of this size

12 Electricity Used 183,640 kWh [5] ÷ [11]

Gas Top Up Boiler


14 Gas Used 416,417.91 kWh [6] ÷ [13]

Emissions Generated by GSHP System

15 Carbon Emission Factor- Electricity 0.41205 kgCO₂/kWh GHG Conversion Factors (UK Gov)

16 Carbon Emission Factor- Gas 0.18400 kgCO₂/kWh GHG Conversion Factors (UK Gov)

17 Carbon Emited by GSHP 75.67 tCO₂ ([12] x [15])

18 Carbon Emited by Gas Top Up Boiler 76.62 tCO₂ ([14] x [16])

19 Total Carbon Emitted 152.29 tCO₂ [17] + [18]

Emissions Saved by GSHP System

20 Base Scenario Thermal Emissions 153 tCO₂ See Baseline

21 Emissions Saved 0.95 tCO₂ [20] - [19]

22 Percentage Reduction 0.62% % [21] ÷ [20]

GSHP Heating System Installation Cost

23 Capital Cost 1046 £/kW AEA Review of Technical Information on RH Technologies

24 GSHP 209,200 £ [2] x [23]



8.3.1 Summary

A ground source heat pump system supplying half the space heating demand would have a capital cost of £225,000. It

would have a simple payback period of 12.4 years and an overall cost benefit of almost £44,417. However, due to the

large electrical consumption of the GSHP system, the GHG emissions savings is only 1 tonne CO2e, which is only 0.3% of

the baseline. Therefore the £/tCO2e p.a. of the GSHP is the highest of all the LZC technologies studied.

25 Top Up Gas Fired Boiler 15,569.18 £ See Constants

26 Total GSHP System Cost 224,769 £ [24] + [25]

27 Baseline Gas Fired Boiler Cost 15,569 £ [4] x £/kW (at 650kW)


28 Electricity Fuel Cost £0.105 £/kWh See Constants

29 Natural Gas Fuel Cost £0.025 £/kWh See Constants

30 Annual Electricty Fuel Cost £19,227.14 £ [12] x [28]

31 Annual Natural Gas Fuel Cost £10,614.49 £ [14] x [29]

32 Total Annual Fuel Cost £29,841.63 £ [30] + [31]

33 Baseline Fuel Cost £21,223.88 £ See Baseline

34 Annual Fuel Cost Compared to Baseline £8,617.75 £ [32] - [33]


35 RHI Tier 1 1314 Hours Number of hours in year x 15%

36 Tier 1 Cons 262,800 kWh [2] x [35]

37 Tier 2 Cons 104,481 kWh [5] - [36]



40 Annual RHI Revenue 26,310.23 £ ([36] x [38]) + ([37] x [39])

CRC Saving

41 CRC cost of allowances £16.10 £/tCO2e GHG Conversion Factors (UK Gov)

42 Annual CRC saving £15 £ p.a. [21] x [41]

Annual Maintenance Cost

43 GSHP Annual Maintenance cost 4 £/kW AEA Review of Technical Information on RH Technologies

44 Gas Boiler Annual Maintenance Cost 2.5 £/kW Value used from previous projects

45 GSHP & Gas Boiler 2,550 £ ([2] x [43]) + ([3] x [44])

46 Base Scenario Gas Boiler 1,750 £ [4] x [44]

47 Total Saving Compare to base line 800- £ [46] - [45]

48 Annual Saving Compared to Baseline £16,908 £ [40] + [47] + [42] - [34]

Simple Payback

49 Payback Cost 209,200 £ [26] - [27]

50 Payback Time 12.4 years [49] ÷ [48]

Life Cycle Cost of GSHP system

51 Lifetime of GSHP system 15 years Lifetime of GSHP System

52 Lifetime net saving £253,617 £ [48] x [51]


54£ CAPEX / annual tCO₂e saved

Greater than

£100,000 £ [26] ÷ [21]

LZC

Net annual

revenue (£ p.a.)

Cost saving

(%)

GHG emissions

saving (tCO2e p.a.)

GHG saving

(%)

CAPEX (£)

Simple payback (years)

Whole life cost / benefit (£

spent / lifetime £ saved)

£ capex / annual tCO2e

saved (£/tCO2e p.a.)

GSHP £16,908 34.0% 1.0 0.3% 224,769 12.4 £44,417 £236,453



9 Air Source Heat Pump (ASHP)

9.1 Introduction

Air source heat pumps [ASHP] draw heat from the ambient outside air during the heating season and reject heat outside

during the summer cooling season. There are two types of commonly available air-source heat pumps, depending on the

heat distribution system in the building.

Air-to-air - The most common is the air-to-air heat pump. It extracts heat/coolth from the outside ambient air and

then transfers it to the building via an air conditioning system.

Air-to-water - The other type is the air-to-water heat pump, which is used in buildings with wet central heating

systems.

The current design proposal is for a wet central heating system, and therefore this report focuses exclusively on the

viability of air-to-water ASHPs. During the heating season, the heat pump takes heat from the outside air and transfers it to

the water in the wet distribution system. If cooling is provided during the summer, the process is reversed and the heat

pump extracts heat from the building.

The temperature of outdoor air is much less stable than that of earth below the ground surface. The CoP [coefficient of

performance] of a heat pump depends predominantly on the temperature difference between the internal environment and

external thermal reservoir, and therefore can significantly vary throughout the year. The seasonal efficiencies [CoPs] of

ASHPs are very susceptible to changes in outside air temperature, and are therefore typically less than those of GSHPs.

On a mild day, when external air temperatures are around 20ºC, an ASHP in heating mode can typically achieve a CoP of

circa 4. However in winter, as outdoor temperatures drop to below 0ºC, the CoP can approach 1.

Furthermore, because the air temperature may drop below 0ºC, moisture in the air may condense and form ice on the

external heat exchanger. This can reduce the heat transfer coefficient, and must be melted periodically using a “defrost

cycle‟ which warms up the external heat exchanger using energy to no useful gain inside the building.

Please note that this report assumes that the proposed ASHP shall be used in heating mode only4.

9.2 Key Considerations

No. Item Details

1 Site / land use

When used as space heating devices, ASHPs achieve their best CoPs when they operate on low flow and return temperatures [e.g. 40/30ºC]. This makes them particularly suitable for use with under floor heating system or with oversized radiators. Consideration should be given to the visual impact associated with any ASHP units installed on the roof.

2 Local planning No local planning constraints have been identified that would prohibit the use of a ASHP system here, however this should be confirmed if this option is pursued.


Consideration should be given to a potential increase in noise associated with an external ASHP.

4 Feasibility of exporting heat / electricity

Exporting heat from a normal ASHP system is not viable due to the relatively low amount of energy generated, and the likely high cost of installing heat export infrastructure.

5 Incentives & grants

The latest applicable renewable heat incentive tariff rates have been incorporated into our cost / benefit calculations.

4 BREEAM only considers ASHP as a renewable technology when used in heating mode/




Baseload Energy - ASHP


1 Heating Demand 734,561 kWh SH Consumption x Boiler Efficiency

2 Size of ASHP 232 kW 58 (kW) x 4, based on 58kW Daikin unit

3 Size of Top Up Gas Boiler 700 kW See Baseline

4 Size of Base Scenario Boiler 700 kW See Baseline

5 Demand met by ASHP 711,312 kWh [2] x 35% x 8760

6 Gas Top Up 23,249 kWh [1] - [5]

Annual Energy Generated - ASHP

7 CoP 2 Typical for ASHP systems

8 Electricity Consumed 355,656 kWh [5] ÷ [7]

Back Up Boiler

9 Gas Boiler Efficiency 88.2% % See Constants

10 Gas Consumption 26,360 kWh [6] ÷ [9]

Emissions Generated by ASHP System

ASHP

11 Energy Used 355,656 kWh [8]

12 Carbon Factor 0.41205 kgCO2/kWh GHG Conversion Factors (UK Gov)

13 Carbon Emitted 146,548 kgCO2 [11] x [12]

Gas Fired Boiler

14 Energy Used 26,360 kWh [10]

15 Carbon Factor 0.1840 kgCO2/kWh GHG Conversion Factors (UK Gov)

16 Carbon Emitted 4,850 kgCO2 [14] x [15]

Total

17 Carbon Emitted 151,398 kgCO2 [13] + [16]

Emissions Saved by ASHP

18 Base Scenario Emissions 153,239 kgCO2 See Baseline

19 ASHP Emissions 151,398 kgCO2 [17]

20 Emissions Saved 1,841 kgCO2 [18] - [19]

21 Percentage Reduction 0.01 % [20] ÷ [18]

Installation Cost

ASHP

22 Size of System 232 kW [2]

23 Installed Cost 156,076 £ Based upon a quote retrieved from Peter Read for UoR Athletics Pavilion, stating £39,019 for a 58kW Diakin system. We have 4x58kW systems

Gas Fired Boiler


24 Installed Cost 15,569 £ See Constants

Total

24 Installed Cost 171,645 £ [23] + [24]


Electricity

25 Fuel Used 355,656 kWh [8]

26 Cost 10.47 p/kWh Table 3.4.1

27 Annual Fuel Cost 37,237 £ [25] x [26]



9.3.1 Summary

The ASHP system has a capital cost of £171,645and net annual revenue of £948, which is a cost saving of ~2%

compared to baseline, and has a payback period longer than the assumed lifetime of the system. It has a similar GHG

emission saving to the GSHP system - 0.7% compared to the baseline scenario. The cause of the low GHG emission

savings for both GSHP and ASHP is due both systems using large amounts of electricity and electricity has a large carbon

emissions factor compared to natural gas.

Natural Gas

28 Fuel Used 26,360 kWh [10]

29 Cost 2.55 p/kWh Table 3.4.1

30 Annual Fuel Cost 672 £ [28] x [29]

Total

31 Annual Fuel Cost 37,909 £ [27] + [30]

Renewable Heat Incentive - ASHP


33 RHI Tariff 0.0254 £/kWh OFGEM Non-domestic RHI Tariffs

34 Demand met by ASHP 711,312 kWh [5]

35 Annual RHI Revenue 18,067 £ [33] x [34]

CRC Saving

36 CRC cost of allowances 16.1 £/tCO2e Gov.uk cost allowance with year 16/17

37 Annual CRC saving 30 £ p.a. [20] x [35]

Annual Costs of ASHP System Compared to the Base Scenario

38 Annual Fuel Cost 37,909 £ [31]

39 Base Scenario Fuel Cost 21,224 £ See Baseline

40 Annual Fuel Costs 16,685 £ [38] - [39]

41 ASHP & Gas Boiler System 2,214 £ [23] x 2.5 + [22] x 2

42 Base Scenario Maintenance Cost 1,750 £ [4] x 2.5

43 Annual Maintenance Saving -464 £ [42] - [41]

44 Annual Saving 948 £ [40] + [43] - [35]

Simple Payback - ASHP

45 Installation Cost 171,645 £ [24]

46 Base Scenario Cost 15,569 £ See Constants (for 700kW boiler)

47 Simple Payback Cost 156,076 £ [45] - [46]

48 Simple Payback Never Years [47] ÷ [44]

Life Cycle Cost of ASHP

49 Life of ASHP System 15 Years See Constants

50 Life Net Revenue 14,216 £ [49] x [44]

51 Whole Life Cost/Benefit -157,429 £ [50] - [24]

52 £ Capex/Annual tCO2e saved 93,235 £/tCO2 [24] ÷ [20]

No. LZC

Net annual

revenue (£

p.a.)

Cost saving

(%)

GHG emissions

saving (tCO2e

p.a.)

GHG

saving (%)CAPEX (£)

Simple

payback

(years)

Whole life cost /

benefit (£ spent /

lifetime £ saved)

£ capex / annual

tCO2e saved

(£/tCO2e p.a.)

7 ASHP £948 1.9% 1.8 0.7% £171,645 Never -£157,429 £93,235



10 Summary

The following table and charts summarise the results of this LZC study.

No. LZC Feasible Sizing principleNet annual

revenue (£ p.a.)

Fuel Cost

saving (%)

GHG

emissions

saving

(tCO2e p.a.)

GHG saving

(%)CAPEX (£)

Simple

payback

(years)

Whole life

cost / benefit

(£ spent /

lifetime £

saved)

£ capex / annual

tCO2e saved (£/tCO2e

p.a.)

Recommended?


heat network (DH)

No; A nearby network is proposed, but none is known to be currently

operating. Allowance for future connection to a district heating scheme

(space for PHX etc.) should be given.

-- -- -- -- -- -- -- -- -- --

2Combined heat &

power (CHP)

No; heat demand profiles inadequate for installation of CHP unit. Run

hours not expected to exceed 4,500hrs/annum required to achieve

commercial viability (Carbon Trust)


CHP, and typical CHP load factor.-- -- -- -- -- -- -- -- --

3Tri-generation (Tri-

gen)

No; localised cooling assumed on-site; too small to be viable for cooling

export. Likely capital costs excessive for the amount of cooling needed.-- -- -- -- -- -- -- -- -- --

4Solar photovoltaic

panels (PV)Yes; Could be installed on Sandfields building roof. % of available roof area. £27,252 54.8% 85.2 31.2% £233,300 8.6 £311,740 £2,700 YES

5Solar thermal hot

water (STHW)Yes; Could be installed on Sandfields building roof.

To provide 100% of HWS demand in

summer£20,090 40.4% 31.8 11.6% £222,700 11.1 £179,100 £7,000 NO


No; As a general rule, a wind speed of less than 4.9 m/s is not

considered to be sufficient to make wind a viable energy source (Natural

Energy). The average wind speeds at the Sandfields school site (SA12


-- -- -- -- -- -- -- -- -- --

7Biomass boilers

(Biomass)Yes; assumed sufficient space in plantroom for plant / fuel store etc.


Biomass, and typical Biomass load

factor.

£7,417 31.3% 64.8 23.7% £111,922 13.0 -£661 £1,727 NO


(ASHP)

Yes; It is assumed that there is sufficient space for an ASHP externally or

in the plant room.

Multiples of 58kW ASHP units from

Daikin to provide 75-90% of space

heating demand

£948 1.9% 1.8 0.7% £171,645 Never -£157,429 £93,235 NO

9Ground source heat

pump (GSHP)

Yes; It is assumed that there is sufficient space for a GSHP externally or

in the plant room.200kW £16,908 34.0% 0.95 0.3% £224,769 12 £44,417

Greater than

£100,000NO

10Water source heat

pump (WSHP)No; No existing suitable waterway nearby. -- -- -- -- -- -- -- -- -- --

11Hydroelectric

generation (Hydro)No; No existing suitable waterway nearby. -- -- -- -- -- -- -- -- -- --

Note: % savings are based on the baseline energy cost and GHG emissions used in this study. How ever, the % savings are different w hen compared w ith the BRUKL document. Further consideration of this is provided in the report.



0.0% 0.0% 0.0%

31.2%

11.6%

0.0% 0.0% 0.7% 0.3% 0.0% 0.0%0%

5%

10%

15%

20%

25%

30%

35%


%

GHG emissions saving as % of baseline

0 0 0

8.6

11.1

0 0 £0

12

0 0 0

2

4

6

8

10

12

14


ye

ars

Simple payback

£0 £0 £0

£2,700

£7,000

£0 £0 £236,453 £0 £0£0

£1,000

£2,000

£3,000

£4,000

£5,000

£6,000

£7,000

£8,000


£/t

CO

2e

p.a

.

£ capex / annual emissions saved

£236,453

£93,235

£0 £0 £0

£311,740

£179,100

£0£0

-£157,429

£44,417£0 £0

-£200,000

-£100,000

£0

£100,000

£200,000

£300,000

£400,000

(£ s

pe

nt

/ li

feti

me

£ s

ave

d)

Whole life cost / benefit



10.1 Overall conclusions and recommendation

Based upon the indicative results provided within this report it is recommended that the use of solar photovoltaics is

considered further:

No significant constraints were identified to the deployment of solar photovoltaics;

Solar photovoltaics offer the greatest level of whole life cost / benefit of all the technologies;

Solar photovoltaics offer the highest level of greenhouse gas emission savings, relative to base case of gas

boilers;

Solar photovoltaics yield the quickest simple payback period, of approximately nine years.

Solar photovoltaics would therefore be the recommended technology to achieve the targeted BREEAM 2014 Ene04 /

Ene01 credit(s), providing that all site constraints and other key considerations can be met or overcome.

The final credits awarded will need to be based on the as-built BRUKL document and as such cannot be guaranteed until

this document has been produced.

10.2 Notes on costings

a) All costs exclude value added taxes.

b) Energy costs and cost savings are based on the energy unit charges as presented in the report. Our study does

not allow for the effects of changing unit charges over time.

c) All CAPEX (capital costs) are based on 2014-15 UK prices and/or known indicators from published documents.

d) The OPEX (operating costs) figures refer to any estimated additional ongoing costs over and above the baseline.

e) The assessment of whole life costs and benefits excludes use of any discount rate, and does not allow for any

inflation or changes in real energy prices, nor does it allow for any degradation in system performance.

f) The calculations in this study EXCLUDE the effects of diminishing marginal returns (DMR). DMR means that

(where applicable) the impact of one project can be subtracted from the starting point of energy demand for

another project which would affect the same demand. A key aspect of applying this methodology is the selection

of the order in which the calculations and diminishing returns are applied. Therefore please note that if certain

technologies are applied in combination then the total impact may be less than the sum of individual impacts

shown for each measure.

g) The objective for this study was to identify and evaluate high-level opportunities for installation of LZCs for the

proposed development. The values presented are therefore indicative only, and any of the considered

technologies would require further investigation and design work before they can be implemented.



11 Appendix

This section contains additional supporting details and data.

11.1 Site information

The approximate heated area was assumed to be the expected gross internal floor area (GIFA) of 6,200m2. The entirety of

the GIFA was assigned to the energy benchmark category of “Schools and seasonal public buildings”. The calculated

values are an indication only, and should not be taken as accurate for the building; however they are sufficient for the

purposes of this study.

11.2 Baseline energy consumption

The following information shows calculations to derive the baseline consumption, from section 3.

Table 10 – Summary of expected energy consumption & GHG emissions

6,200

GHG emissions **

kWh/m2 kWh p.a. p/kWh £ p.a. kgCO2e/kWh tCO2e

Electricity 40 248,000 10.47 £26,000 0.41205 102

Gas 150 930,000 2.55 £23,700 0.18400 171

Cost *Utility

Schools and seasonal public buildings

Energy benchmarks

Total Consumption kWh p.a. Cost GHG emissions

Electricity 248,000 26,000 102

Gas (Total) 930,000 23,700 171

Gas (Hot water) 97,164 2,476 18

Gas (Space heating) 832,836 21,224 153

OVERALL TOTALS 1,178,000 49,700 273



11.3 Biomass (Wood Pellets) – System sizing and cost / benefit

The following information shows calculations for the Biomass wood pellet boiler to derive the cost, emissions savings, and

payback period of the wood pellet boiler, from section 8.3.1.

Sizing a biomass boiler


1 Rated Output [kW] 200 kW

2 Modulation 30% % Rule of thumb for Biomass systems

3 Minimum Output [kW] 60.0 kW [1] x [2]

RequiredEnergy of Biomass

4 SH & DHW Demand 930,000 kWh Baseline figue

5 Demand Met by System 465000 kWh [4] x 0.5

6 Boiler Size 200 kW [1]

7 Efficiency of Boiler 80% % Typical for Biomass systems

8 Required Energy Delivered 581,250 kWh [5] ÷ [7]

Required Energy of Gas

9 Demand Met by System 465,000 kWh [4] - [5]

10 Boiler Size 700 kW See Baseline


12 Required Energy Delivered 527,210.88 kWh [9] ÷ [11]

Fuel Required (Wood Pellets)


14 Fuel Required 123,670.21 kg [8] ÷ [13]

Sizing Fuel Store (Wood Pellets)


16 Operating Hours 100 hours CIBSE Guide B section 1.6.3.4

17 Efficiency 80% % [7]


19 Density 650 kg/m³ CIBSE KS10 Table 1

20 Volume 8.2 m³ ([15]x[100])/[17]/[18]/[19]

Emissions Generated by Biomass Heating System

Gas

21 Emission Factor 0.184 kgCO₂/kWh See constants


Wood Pellets

23 Emission Factor 0.039 kgCO₂/kWh SAP 2012 Table 12


25 Total Emissions Generated 119,674 kgCO₂ [22]+[24]

Emissions Saved by Biomass

26 Base Scenario Emissions 171,117 kgCO₂ Baseline calculations

27 Emissions Saved 51,443.166 kgCO₂ [26]-[25]

28 Total Emissions 273,305.441 kgCO₂ Baseline calculations

29 Percentage Reduction 18.823% % [27]÷ [28]

30 CRC cost of allowances 16.1 £ / tCO2e Gov.uk cost allowance with year 16/17

31 Annual CRC saving 828.235 £ p.a. [27]x[30]



Installation Cost

No. Part Price £ Source

32 Biomass boiler w/ ancillaries 50,132.50 £ scaled from previous quote

33 Biomass - buffer [litres] 10,000.00 £ £1 per litre, volume = 50 x rated output

34 Biomass - fuel store [m3] 8,773.43 £ scaled from previous quote

35 Gas boiler 700kW 15,569.18 £ See Constants

36 Total 84,475.12 £ [32]+[33]+[34]+[35]


Gas

37 Cost £0.02 £/kWh


Wood Pellets

39 Cost £0.04 £/kWh Biomass Energy Centre




42 RHI Tier 1 1,314 Hours 8760 x 15%

43 Tier 1 kWh 262,800 kWh [41]x[42]

44 Tier 2 kWh 202,200 kWh [5]-[43]



47 Tier 1 Revenue 13,770.72 £ [43]x[45]

48 Tier 2 Revenue 4,589.94 £ [44]x[46]

49 Annual RHI Revenue 18,360.66 £ [47]+[48]

Annual Cost of System

50 Maintenance Cost [Biomass] 4,400.00 £ AEA for DECC review

51 Maintenance Cost [Gas] £0.10 £

52 Total Cost 21,857.63 £ [38]+[40]+[50]+[51]-[49]-[31]

Base Scenerio Annual Cost (Gas Boiler Only)

53 Base Scenario Heating Cost 23,700.00 £ Baseline calculations

54 Maintenance Cost 1,751.50 £

55 Total Cost 25,451.50 £ [53]+[54]

Pay Back & life-cycle cost effectiveness ratio

56 Biomass Installation Cost 109,197.57 £ [36]

57 Base Scenario Cost 12,874.81 £ Cost of 450kW boiler

58 Simple Payback Cost 96,322.76 £ [56]-[57]

59 Annual Saving £3,593.87 £ [55]-[52]

60 Simple Payback [Years] Never Years [58]/[59]

61 Lifetime of system 15 Typical for Biomass systems

62 Lifetime of net saving 53,908.03 £ [59]x[61]

63 Whole life cost / benefit -55,289.54 £ [62]-[56]

64 £CAPEX / annual tCO2e saved £2,122.68 £ [56]x([27]/1000)

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Neath Port Talbot Sandfields Secondary School

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