Feasibility of supercritical CO2 coaxial heat exchanger geothermal well conversion with ECO2G technology

Abstract

The feasibility of converting non-producing geothermal wells to closed loop supercritical CO2 coaxial heat exchanger using ECO2G technology was analyzed for two heat exchanger scenarios. The first scenario, Case A, utilizes the existing production casing as the heat exchanger and plugs the well at 1000 m depth to create the closed loop. The second scenario, Case B, inserts a new, closed, hang-down liner to the full 2500 m depth to use as the heat exchanger. A spreadsheet thermodynamic model discretized the depth of the well to model the heat flow, temperature and pressure of the sCO2, and electricity production of each heat exchanger. With the electricity production, the NPV and IRR of Case A and Case B were performed, along with a sensitivity analysis. From this study, the feasibility of the project was determined.