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ANNEX 1 UPDATEIEA-GIA ExCo Meeting, Taupo, 30th April, 2015

Geothermal Environmental Tasks

Chris Bromley

GNS Science, WairakeiResearch Centre, Taupo,

New Zealand

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Task Descriptions

A. Impacts on natural features

B. Discharge and reinjection problems (chemicals, gas, subsidence)

C. Methods and costs of adverse impact mitigation, (successful policies and strategies)

D. Sustainability

Participating countries

Annex 1 : Australia,

Iceland, Italy, Japan,

Mexico, New Zealand,

Norway, Switzerland &

the United States

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Outcomes from previous Annex 1 Meetings

1. Review tables of best practice procedures and

risks: environmental priorities for participants

2. Compilation of outputs, fact sheets, a reference

list : draft structure (for GIA website)

3. US – guidelines to streamline approvals

4. Japan – development protocols in national parks

5. Iceland – sustainability modelling, protocol,

deep roots (new annex)

6. New Zealand – subsidence, spring protection &

feature/system ranking

7. Other tasks and other people ?

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Highlights of WGC2015 presentations on

environmental and social topics from IEA-GIA

member countries : Switzerland, France,

Japan, Canada, NZ, & Iceland

Sessions: 3E, 4E, 5E, 6D, 9D, 10D

Sustainability sessions :Sessions 7J , 19C

Bromley, Axelsson and Mongillo “Sustainable and

environmentally sound development strategies

addressed through international collaboration.” 05000

Axelsson et al, “Renewability Assessment of

Reykjanes”, 16008

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Summary of Subsidence anomalies in NZ

geothermal fields

5

NZ Geothermal subsidence summary

Field & bowl Total Max rate Year max Current rate

m mm/yr yr mm/yr

Wairakei Valley 15 500 1974 50

Ohaaki West 6 400 1994 170

Tauhara- Spa Valley 3 110 2005 110

Tauhara- Crown Rd 1 60 2004 20

Kawerau 0.75 50 2012 50

Mokai (injection) 0.2 30 2009 10

Rotokawa (injection) 0.2 50 2007 10

Ngawha 0.03 3 2012 3

Bromley et al “Subsidence : an Update on New Zealand

Geothermal Deformation Observations and

Mechanisms” paper 02021

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Repeat infrared surveys to map changes

1989 1998 2013

Reeves, Bromley & Milloy, (WGC)

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Sustainable Use Flowchart

a ‘snakes and ladders’ approach from

Bromley and Axelsson paper 05000

1. Exploration & Resource

Assessment

2. Initial Capacity for Staged Approach

3. Natural-State Simulation Model

6. DecideTiming of Multiple Stage

Expansions

5. Calibrate Reservoir Model

4. Produce & Monitor Reservoir Response

7. Expand & Stimulate Reservoir

Response

8. Achieve Enhanced Hot

Recharge

9. Apply Adaptive Reinjection Strategy

12. Decide Long-Term Strategy :

Rotate(heat-grazing)

11. Make-up Drilling Options: in or out

10. Refine Simulations (loop back to 6 or 9);

13. Refine Resource Boundary Conditions

14. Improve Simulations (loop

back to 11)

15. CELEBRATE SUCCESS!

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Annex compendium of recent outputs• 2012-13 Meetings (& reports) in Oslo, Pisa, Mexico,

Philippines

• IEA-GIA convened “Environmental Mitigation

Workshop” Taupo, New Zealand, 15-16 June 2012

• Papers on subsidence, monitoring heat-flux by

satellite & infrared (WGC2015 papers)

• Chapter on ‘Geothermal Power’ in Renewable

Energy book, with focus on sustainability

• Thesis on sustainability protocol (indicators )

• Presentations & papers in Italy, Germany, China,

New Zealand, & Iceland, dealing with environmental

and sustainability or modelling issues.

• Special Issues, workshops, encyclopedia, websites

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Sustainability ProtocolIceland/NZ/Kenya PhD project.

Ranking of Indicators of Project Sustainability:

environmental, economic & social (summary)

See WGC2015 paper 05020 Shorthall and Davidsdottir

session 7J

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Work Plan in support of 2013-2018 Strategic Plan

Task A. Impacts on Natural Features – establish protocols and methods of

drilling/producing/injecting deep beneath protected areas with negligible

surface impact.

Task B. Discharge and Reinjection Problems – mitigate deposition/

corrosion; document results of subsidence mitigation by injection;

investigate biochemical remediation/ treatment of condensates; monitor

casing integrity to protect groundwater.

Task C. Methods and Costs of Adverse Impact Mitigation – rank geothermal

systems for protection status using appropriate categories & criteria;

streamline EIA timeframes by standardising common issues and good

practice procedures through programmatic approach; itemize experience

and best practice options for cooling, stimulation and make-up water

resource issues for EGS projects.

Task D. Sustainability – publish more case studies; investigate permeability

changes with time & interference between neighbouring systems; design &

test a geothermal sustainability protocol; plan make-up production from

recharge zones & improve the use of tracers for predictive modelling of

long-term reservoir performance

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Annex 1 : developing some new ideas1- methods of drilling/producing/injecting deep beneath protected

areas with negligible surface impact

2- subsidence mitigation by injection – documenting results,

separating different mechanisms;

3- EGS stimulation chemicals and proppants - methods of

avoiding groundwater contamination ;

4- biochemical remediation/treatment of condensates ;

5- monitoring of casing integrity to protect groundwater

6- ranking of geothermal systems for protection/ preservation/

research /limited/ development : using appropriate categories and

criteria.

7- EIA timeframe streamlining by standardising common issues

and good practice procedures

8- cooling, stimulation and make-up water resource issues

9- use of Tracers to monitor and manage sustainable reservoir

performance and long term reinjection

NEW DIRECTIONS.. ?

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Discussions on Sustainability

• Sustainable utilisation : improve reservoir knowledge;

advanced modelling tools

• Temperature changes - cold inflows, dual tracer tests

(volume & area), boundary conditions, coupled modelling-

(MT, seismicity, deformation, gravity), EGS models (heat

recovery), supercritical conditions, Tough-react

(dissolution/ deposition), fracture propagation, long-term

thermo-elastic effects, strain & fracturing characteristics

• Social, environmental, economic & reservoir sustainability

protocols

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Thank You