A case study of using sCO2 equipment in different geothermal energy systems: AGS, EGS and CPG

Climate change necessitates innovative solutions for producing clean energy and decreasing atmospheric CO2 levels. Using CO2 as a working fluid in geothermal applications is a smart strategy to achieve this goal, as it has the potential to outperform conventional water-driven geothermal systems in terms of power produced, and for some cases, simultaneously increase the amount of CO2 that can be geologically sequestered. Power plant technology plays an important role in maximizing the value of geothermal resources. This is achieved through versatile power plant components that, barring large differences in CO2 purity, can operate across various geothermal systems. This research compares the use of similar power plant components and technologies across various types of CO2-based geothermal energy systems: hydrothermal systems with CO2 as a secondary working fluid, Advanced Geothermal Systems (AGS), Enhanced Geothermal Systems (EGS), and CO2-Plume Geothermal (CPG) systems. After providing ranges in possible operating conditions of these systems, the study employs TANGO (Techno-economic Analysis of Geo-energy Operations) to calculate the extracted energy and the Levelized Cost of Electricity (LCOE) for an example AGS, EGS, and CPG project, each with 10 MWe installed capacity. The findings indicate that CO2 is an effective geothermal working fluid and that most CO2 equipment can be used across the different geothermal systems. Given the extensive drilling required for AGS, LCOEs of CPG and EGS were found to be more competitive at current well construction costs.