EGU23-7705, updated on 11 Jan 2024
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Assessing carbon mineralization using an integrated approach at the Nesjavellir geothermal field, Iceland

Deirdre Clark1, Kjartan Marteinsson1, Gunnar Þorgilsson1, Iwona Galeczka1, Helga Helgadóttir1, Sandra Snæbjörnsdóttir2, Bergur Sigfusson2, and Sveinborg Gunnarsdóttir1
Deirdre Clark et al.
  • 1Iceland GeoSurvey, Kópavogur, Iceland (
  • 2Carbfix hf., Kópavogur, Iceland

The Nesjavellir high-temperature geothermal field in Iceland was chosen as part of the GECO H2020 project to further demonstrate the Carbfix method of carbon mineralization. In this method, geothermal power plant emissions of CO2 and H2S are captured using condensed steam, and subsequently co-injected with separated geothermal water into the subsurface where they mineralize in the form of carbonate and sulfide minerals. This technology has already been successfully shown to be a safe and cost-effective approach to reduce gas emissions from the nearby Hellisheiði geothermal power plant in SW Iceland.

An integration of geology, reservoir and geochemical models were used to evaluate the future injection of CO2 and H2S at the Nesjavellir site. These models include reservoir parameters such as the relative permeability and porosity of different stratigraphic layers as well as the locations of feedzones. Tracer tests and well temperature and pressure logs were used to calibrate single porosity and dual porosity TOUGH2 flow models. A 1-D flow reactive transport model was then created using TOUGHREACT and the parameters from the flow models and calibrated using chemical compositions of the reservoir background fluid and separated water, the proposed gas injection fluid chemistry and available bulk rock chemistry and lithological data from borehole reports. Results from this integrated approach offer possible controls on the flow, impacts of the CO2-H2S injection, and estimate the potential storage capacity of carbon mineralization within the Nesjavellir geothermal reservoir.

How to cite: Clark, D., Marteinsson, K., Þorgilsson, G., Galeczka, I., Helgadóttir, H., Snæbjörnsdóttir, S., Sigfusson, B., and Gunnarsdóttir, S.: Assessing carbon mineralization using an integrated approach at the Nesjavellir geothermal field, Iceland, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7705,, 2023.