CO2-Plume Geothermal
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CO2-Plume Geothermal (CPG) is a proposed technology that combines Carbon Capture and Storage (CCS) with geothermal energy extraction, utilising CO2 itself as a geothermal energy extraction fluid.[1][2][3]
Technology
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First, CO2 would be injected in deep and naturally permeable reservoirs, just like in CCS, where the CO2 would be heated by the surrounding hot rocks. At a nearby location, production wells would then extract the geothermally heated supercritical CO2 back to the land surface,[4] where it would be expanded in a CO2 turbine to generate electricity.[5] The CO2 would then cooled and condensed back to a dense phase and re-injected into the reservoir, closing the cycle and enabling all CO2 to be permanently sequestered.[1] CPG has the potential to generate over twice the power of conventional, water-based geothermal systems for similar conditions:[6] while the specific heat capacity of CO2 is less than that of water, the significantly lower dynamic viscosity of CO2 would enable higher overall energy extraction rates.[7]
Over 14 peer reviewed publications have been published on CPG as of 2024 since its invention by Martin Saar and Jimmy Randolph in 2011.[8][clarification needed]
Relation to CCS projects
[edit]As the subsurface reservoir cools due to geothermal heat extraction, the density of CO2 in the subsurface increases, enabling a larger mass to be stored for a given formation.[9] Other identified impacts of CPG on CCS include increased control over CO2 volumetric sweep, reduced carbon intensity of storage due to renewable energy production, additional monitoring data from production wells, flexibility to repurpose producer wells to injectors, avoiding injector downtime with associated halite deposition risks, and providing communities with power produced using CO2.[9]
Research needs
[edit]While existing equipment from CO2 EOR and CCS projects could be repurposed for CPG, new equipment is required, primarily lower temperature supercritical turbines and high-pressure CO2 cooling and condensing units.[5]
References
[edit]- ^ a b Randolph, Jimmy; Saar, Martin O. (2011). "Combining geothermal energy capture with geologic carbon dioxide sequestration". Geophysical Research Letters. 38 (10). Bibcode:2011GeoRL..3810401R. doi:10.1029/2011GL047265.
- ^ Norouzi, Amir Mohammad; Fatemeh, Rabbani; Fowler, Neil; Gluyas, Jon; Niasar, Vahid; Ezekiel, Justin; Babaei, Masoud (Dec 27, 2022). "CO2-plume geothermal: Power net generation from 3D fluvial aquifers". Applied Energy. 332. doi:10.1016/j.apenergy.2022.120546. Retrieved 9 August 2024.
- ^ Chen, Mingjie; Nikoo, Mohammad Reza; Al-Maktoumi, Ali; Izady, Azizallah; Rajabi, Mohammad Mahdi Rajabi (17 December 2022). "The impact of geological heterogeneity on coupled CO2 storage and geothermal extraction in inclined reservoirs". Journal of Hydrology. 617. doi:10.1016/j.jhydrol.2022.128950. Retrieved 9 August 2024.
- ^ Ezekiel, Justin; Adams, Benjamin M; Saar, Martin O.; Ebigbo, Anomie (2022). "Numerical analysis and optimization of the performance of CO2-Plume Geothermal (CPG) production wells and implications for electric power generation". Geothermics. 98. doi:10.1016/j.geothermics.2021.102270.
- ^ a b Schifflechner, Christopher; de Reus, Adriaan Jasper; Schuster, Sebastian; Villasana, Andreas Corpancho; Brillert, Dieter; Saar, Martin O.; Spliethoff, Harmut (2024). "Paving the way for CO2-Plume Geothermal (CPG) systems: A perspective on the CO2 surface equipment". Energy. 305. doi:10.1016/j.energy.2024.132258. Retrieved 9 August 2024.
- ^ Adams, Benjamin M.; Kuehn, Thomas H.; Bielicki, Jeffrey M.; Randolph, Jimmy B.; Saar, Martin O. (15 February 2015). "A comparison of electric power output of CO2 Plume Geothermal (CPG) and brine geothermal systems for varying reservoir conditions". Applied Energy. 140: 365–377. doi:10.1016/j.apenergy.2014.11.043. ISSN 0306-2619. Retrieved 9 August 2024.
- ^ Brown, Donald W. (2000). "A hot dry rock geothermal energy concept utilizing supercritical CO2 instead of water" (PDF). Proceedings of the Twenty-Fifth Workshop on Geothermal Reservoir Engineering. 25: 233–238.
- ^ "CPG Consortium". Retrieved 15 May 2024.
- ^ a b Saar, Martin. "How CCS can benefit from CO2-Plume Geothermal (CPG)" (PDF). Caprock Integrity & Gas Storage Symposium. Swisstopo. Retrieved 15 May 2024.