The existing U.S. fleet of geothermal power plants uses conventional, or “hydrothermal,” resources that rely on existing subsurface heat, fluid or water, and permeability (the ability for that fluid to flow). Hydrothermal projects involve a production well, which draws hot water or fluid to the surface; a surface generator, which converts the hot fluid into steam to power a turbine; and an injection well, which re-injects the cooled fluid back into the ground. These types of geothermal projects require naturally occurring subsurface conditions to enable the fluid to permeate across to the production well, getting re-heated as it travels. According to DOE’s GeoVision analysis, improving techniques, tools, and methodologies can help discover and develop more hydrothermal resources. Of an estimated 40 gigawatts (GW) of hydrothermal energy production potential, only about 9 GW has been identified. Using innovative designs in new plants can also help the United States fully tap this abundant source of renewable energy.
By contrast, next-generation geothermal technologies use engineering to access ubiquitous underground heat, creating geothermal power resources where they would not otherwise exist. Directional drilling and hydraulic fracturing advances allow water to flow through hot rock where no fractures naturally occurred. Because there is no unique geologic constraint, next-generation geothermal technologies have effectively limitless potential. DOE’s 2023 Enhanced Geothermal Shot™ analysis confirms the potential for as much as 90 GW of installed EGS capacity by 2050, and forthcoming DOE analysis shows upside of over 300 GW in certain economic scenarios. However, there are an estimated 5,500 GW of heat resources available throughout the United States alone. Advancing next-generation geothermal could enable the country to tap more of those resources nationwide. In addition to heat resources throughout the U.S. West, there are also hundreds of GW of potential next-generation geothermal resources in the Eastern United States.
Two approaches to next-generation geothermal, EGS and closed loop geothermal systems, have both completed successful pilot projects, and EGS is already producing electricity on the U.S. grid. EGS use injection and fracture technologies to create humanmade reservoirs that facilitate capture of subsurface heat. Closed loop geothermal systems drill ultra-deep well loops that allow continual fluid circulation through the bedrock without creating fractures.
In September 2022, DOE launched the Enhanced Geothermal Shot™, which aims to decrease the cost of EGS power by 90% to $45 per megawatt-hour by 2035. This effort includes developing better mapping and modeling, faster and more efficient drilling, and improved fluid control. DOE’s Geothermal Technologies Office (GTO) is also conducting research, development, and demonstration to advance geothermal power production, including three new EGS demonstration projects funded by President Biden’s Bipartisan Infrastructure Law.
As state and federal clean energy goals get more aggressive, and intermittent solar and wind power plants scale up, the value of clean, firm geothermal power to the grid increases significantly. In 2021, the California Public Utilities Commission mandated the procurement of 1 GW of clean, firm power by 2026; geothermal power is poised to help the state reach this goal. Corporations that have 24/7 clean energy targets are now beginning to invest in geothermal projects to help meet their climate goals. Industry is taking notice of the opportunities to create more geothermal power production, too, with multiple companies raising equity capital to develop next-generation geothermal approaches and demonstrate pilot plants.
HOW LPO CAN HELP
DOE’s GeoVision analysis estimates that, with technology improvements, geothermal electricity generation has the potential to increase 26-fold in the United States by 2050. The Enhanced…
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