Cost-Effective Geothermal Systems for Permanent Military Bases

Geothermal is on the verge of a revolution in applicability and it provides an infinite clean and renewable source of energy available 24/7. Challenges for geothermal include exploration risks, low heat harvesting efficiency as rock has poor thermal conductivity, low efficiency of the overall system, and high capital costs. Sage Geosystems™ (Sage) is the only company working to address these challenges with an integrated system approach covering both surface (plant) and subsurface (well) to deliver a higher heat harvesting efficiency at a lower capital cost. This approach is like that used successfully for years in the oil and gas industry for complex plays like the Arctic. Sage is also unique in that we recognize there is no single optimum geothermal design solution for all applications and subsurface environments, so we have developed multiple technologies for addressing the challenges, with these recommendations informed by our powerhouse modeling tool. This proprietary tool is based on decades of experience modeling subsurface fluids and processes in the drilling of oil and gas wells and will allow Sage to rapidly target surface and subsurface designs and combinations thereof to optimize the power generated from and cost of geothermal systems. Sage has four areas of proprietary technologies that, when proven successful, provide the opportunity for commercial geothermal power generation by targeting largely undeveloped sedimentary formations and bottom hole temperatures of 150-250°C which exist at reasonable depths below most DoD installations. Off-the-shelf oilfield technology and know-how that is field-proven can be used to drill and stimulate these wells at a low cost and without causing induced seismicity. Sage has also developed technologies that utilize supercritical CO2 (sCO2) as the working fluid and a specially designed sCO2 turbine. sCO2 reduces friction and increases natural thermosiphon, and the sCO2 turbine is significantly smaller than a traditional steam turbine resulting in a reduced surface (plant) equipment cost. Sage’s technologies can be either closed loop or a hybrid design to maximize heat harvesting while reducing upfront costs and increasing the total power output.  Our Phase II proposal, working in conjunction with the Bureau of Economic Geology (BEG), is to deepen the feasibility study from Phase I for installing a 3MW geothermal microgrid power plant in 2022 dedicated to the Ellington Field Joint Reserve Base in Houston, TX. The deliverables of Phase II will be to: (1) finalize the subsurface geologic study, (2) select the optimum drilling location within the base property, (3) finalize the geothermal and well(s) design, (4) finalize the design of the 3MW plant including the sCO2 turbine and associated equipment, and (5) initiate the induced seismicity monitoring program to create a baseline for the site and complete an environmental assessment.