MSc Thesis: Feasibility of Supercritical CO2 Coaxial Heat Exchanger for Geothermal Well Conversion with ECO2G Technology

Lauren Hillis successfully defends her master's thesis


REYKJAVIK, June 1 – Master's candidate of Sustainable Energy Engineering, Lauren Hillis, has just successfully delivered her master's thesis project, conducting a feasibility study of a super-critical CO2 coaxial heat exchanger for geothermal well conversion with ECO2G technology. Throughout her work, Lauren was supervised by Dr. María Sigríður Guðjónsdóttir, Professor here at Reykjavik University, Sverrir Þórhallsson, Engineer at ISOR, and Joseph Scherer, CEO of GreenFire Energy Inc..


Lauren defended a closed thesis, working in collaboration with GreenFire Energy Inc. and their ECO2G technology, though was able to shed some light on her masters level research in this exclusive article. Lauren explains that 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, utilized the existing production casing as the heat exchanger and plugged 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. 

Under these two scenarios, Lauren used a spreadsheet thermodynamic model discretized the depth of the well to model the heat flow, temperature and pressure of the CO2, and electricity production of each heat exchanger. With the electricity production found, Lauren then produced a financial model by calculating the net present value and internal rate of return for the project. Afterwards, with the financial model and a sensitivity analysis done on electricity prices, a break-even price was found for each case.

Lauren thus concluded the feasibility of the project, helping the progression and advancement of the ECO2G technology considered throughout her work. Congratulations Lauren on an excellent thesis!


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