Carb-Fix (CO 2 fixation into basalt) Experiment at Hellisheiði Geothermal Plant, Iceland

1. Carb-Fix (CO2 fixation into basalt) Experiment at Hellisheiði Geothermal Plant, Iceland by Hólmfríður Sigurðardóttir Project Manager Reykjavik Energy Contact: holmfridur.sigurdardottir@or.is

2. Jan 2006 Wally Broecker invited by President of Iceland to give a lecture on climate change” Workshop in Reykjavík January 16th -17th 2006 Cooperation University of Iceland - www.raunvis.hi.is Columbia University - www.ldeo.columbia.edu CNRS in France - www.cnrs.fr Reykjavík Energy – www.or.is The Future • CO2 strapped from the atmosphere The Beginning

3. Ingvar Sigurðsson • Basalt is igneous rock formed during volcanic eruptions • Can be glassy and/or crystalline • Basalt contains about 10 weight% CaO which can be used for carbon fixation

4. Bedrock > 90% basaltic Excellent infrastructure for experiment at Hellisheiði plant Ample supply of fresh water, CO2 gas and dissolvable basalts Group of scientist, engineers and craftsmen Fundamental equations describing rate of basalt dissolution Study may prove the feasibility of CO2 fixation projects elsewhere Why Iceland? Basalt Sigfús Már Pétursson Sigfús Már Pétursson Guðmundur Lárusson

5. Icelanders ~3.7 Mt CO2 /yr (figures from 2004) Energy from fossil fuel 52% Industrial processes 25% Agriculture 14% Waste 5% Geothermal energy 4% Geothermal power plants (450 MW): 20-40 g CO2/kWh Comparison of CO2 emission from different energy sources in the USA (Bloomfield et al. 2003) Natural gas: 599 g CO2/kWh Oil: 893 g CO2/kWh Coal: 955 g CO2/kWh Magma: ~ 2 Mt CO2 /yr Iceland - CO2 Emission Sigfús Már Pétursson Sigurður R Gíslason

6. Fumaroles Hot spring areas, fumaroles Recharge by cold ground-water Upflow zone 280-320 °C Lateral outflow zone, 220-280 °C 350-400 °C Deep inflow zone Alteration cap Supercritical convection 600-1000 °C Heat conduction and natural CO2 release Outer boundary: 100 °C/km and constant pressure Solidifying magma Natural Processes

7. CO2 Captured Naturally in Hellisheiði Depth (meters above sea level)

8. CO2 in geothermal steam from wells at Hellisheiði CO2 fully dissolved in fresh water and injected down to 400-800 m Add calcite to the alteration cap Alteration cap Gretar Ívarsson Heat conduction and natural CO2 release Solidifying magma

9. Gas injected fully dissolved in water into target zone 1 kg/s of CO2 from condensers Groundwater Target zone for CO2 sequestration identified at 400-800 m depth 400 kg/s of steam, gas and water from deep and hot (>240 °C) geothermal wells Hellisheiði geothermal power plant Sigfús Már Pétursson

10. The gas mixture: 0,5 % of the steam is geothermal gas Gas mass% CO2 83 H2S 16 CH4 N2 ~1 H2 ~13 l/s of water to dissolve 1 kg/s CO2 at 25°C and 40 bar ~ 10 kg basalt to react with 1 kg/s CO2 Sigfús Már Pétursson

11. An initial tracer test at the target zone for CO2-injection Nature of the groundwater system Flow-patterns and flow-rates Large dispersion Matrix permeability – not through fractures Large surface area for chemical reactions Ensure that a potentially leaky site is not selected Tracer Tests Guðmundur Lárusson Gretar Ívarsson

12. Compression, refrigeration and distillation: 98% CO2 and 2% H2S as a liquid H2 ,possibly applicable as fuel Estimated cost: 1MW/yr of electricity needed for the process and injection 1% of the electricity production at Hellisheiði geothermal plant CO2 Separated from the Gas Mixture Sigurður R Gíslason

13. Bedrock and Boreholes HN-4 HK-31 CO2 injection well - HN-2 Fresh water - HN-1 Casing Lavaflows Hyaloclastite formations Upper level of alteration minerals Bedrock temperature Flow direction

14. The Process Injection well: CO2 fully dissolved in fresh water pH increases Low pH: 3-4 Dissolution of basalt  release of Ca2+ and other ions Precipitation of calcite • Reservoir may gradually clog up with calcite scaling • Natural process in high-temperature systems

15. Law and regulations Prevention of contaminating groundwater Health and safety Planning act, Nature conservation law Operating permits Environmental impacts Surface: Perturbation of pristine areas, visual impacts, suffocation etc. Subsurface: Metal mobilization, groundwater contamination etc. Air: Leakage of CO2 back to the atmosphere Site monitoring and verification Regulatory Frameworks Reykjavik Energy

16. Soil CO2 flux – before and after injection Tracers and chemical analysis Geophysical signals Resistivity Gravity Site Monitoring National Energy Authority

17. Extensive basalt shields worldwide Global Significance

18. Extensive basalt shields worldwide Mineral stable for thousands or millions of years The experiment will address whether mineral storage of CO2 in basalts is a global alternative The project may demonstrate that “zero emission” geothermal power plants are possible New technology for strapping CO2 from the atmosphere – sequestration projects can be operated at “best” geological conditions Global Significance