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Review of CO₂-Plume and CO₂-Based Geothermal Systems: Progress, Thermodynamics, and Field-Scale Challenges
Alireza BIGDELI, Yusuf PAMUKCU, Coşkun ÇETIN, Gökhan KARCIOGLU, Cenk TEMIZEL
[Istanbul University-Cerrahpasa, Turkey]
The implementation of geothermal energy generation and Carbon Capture Utilization and Storage (CCUS) technologies opens the door to a new pathway to long term, baseload renewable energy The potential for the use of geothermal energy generation along with Carbon Capture Utilization and Storage (CCUS) technologies creates a pathway to a renewable energy source capable of providing baseload power and to store CO2 long-term. The author discusses the development of geothermal systems that are operated using CO2 as the working fluid. There are two primary approaches: CO2-Enhanced Geothermal Systems (CO2-EGS) that operate within crystalline basement rock; and CO2-Plume Geothermal (CPG) that operates in sedimentary aquifers. The authors have compared the thermophysical properties of supercritical CO2 (scCO2) to those of water. The authors noted that a self-sustaining thermosiphon effect generated by the large temperature/density gradient of scCO2 was an important consideration when comparing the thermosiphon effect's ability to minimize parasitic pump loads by allowing the thermosiphon effect to either completely or significantly decrease parasitic pump loads. The authors identified the transition from theoretical application to practical deployment of CPG technology can be difficult because of the many barriers to overcome that occur as a direct result of interactions between the various subsurface elements. Therefore, the authors have included extensive discussion on geochemistry topics including salt precipitation in the capillary regime through simulations and mineral dissolution effects on the increase of porosity through Damköhler and Péclet numbers. Additionally, the authors evaluated the risk of failure of wellbore integrity caused by exposure to carbonic acid, including the degradation of Portland cement and the corrosion of steel. The authors evaluated techno-economic models (genGEO) that indicate that CPG can achieve a competitive levelized cost of electricity (LCOE) when paired with carbon credits, including the US 45Q tax credit. The authors evaluated field data from the SECARB Cranfield test and GreenFire Energy's closed-loop demonstration at Coso to validate the accuracy of their numerical model of CPG versus actual performance in the field, and demonstrated the differences between open and closed-loop system performance.
Topic: Reservoir Engineering