Techno-economic assessment of large-scale sedimentary basin stored–CO2 geothermal power generation

Abstract

One approach to reducing atmospheric carbon dioxide (CO 2 ) emissions is to adopt carbon capture utilization and storage (CCUS) strategies. This is particularly crucial for countries to achieve their net-zero goal. In this study, we investigate the techno-economic viability of a proposed CCUS process that utilizes geologically stored CO 2 , associated with hydrogen (H 2 ) production from fossil fuels, as a working fluid to extract geothermal energy from deep, large-scale, sedimentary storage formations. The process ensures permanent geological storage of all injected CO 2 while generating adaptable geothermal power through supercritical CO 2 turbine expansion, thus, bolstering revenue and reducing the final cost of blue hydrogen production. We simulate subsurface-wellbore fluid flow and heat transport for a representative 4-way closed anticlinal Arabian reservoir and optimize system power output, including a comprehensive and integrated economic analysis. We find that CO 2 captured from an equivalent blue H 2 production of ∼4.1 Mt./year can be injected at an annual rate of 0.92–1 million metric tons (Mt) per well, resulting in a cumulative sequestration of ∼1.15 gigatons (Gt) of CO 2 over 11.5 years. To mitigate the risks of reaching the formation parting pressure at the crest of the anticline and ensuring sufficient CO 2 saturation at the production wells, phased drilling schedules and pressure-controlled injection and production are essential. With horizontal production wells, our simulations generate an average geothermal net electricity of 164 MW. The base-case economic analysis reveals a Levelized Cost of Electricity (LCOE) of 77 $/MWh and a Net Present Value (NPV) of 480 million USD over 50 years. In contrast, vertical production wells double LCOE, and the project remains unprofitable throughout its life (negative NPV). Our economic sensitivity analysis further emphasizes how the capacity factor, electricity selling price, and drilling costs govern LCOE and NPV. On the other hand, discount rates and Opex fraction are influential yet uncertain parameters affecting the system's techno-economic outlook. Therefore, our study provides valuable insights into the benefits of geothermal energy production from over 1 Gt of stored CO 2 and the associated economic landscape. • A thorough techno-economic analysis of large-scale CO2-based geothermal systems is presented. • Phased drilling schedules and pressure-controlled development strategies offer power generation and economic advantages. • Projected LCOE is 77 $/MWh utilizing horizontal production wells, while vertical production wells double LCOE (infeasible). • A sensitivity analysis on the impact of economic parameters on LCOE and NPV is presented. • We emphasize a synergistic CCUS approach to achieve decarbonization goals, along with its limitations.

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