The U.S. Department of Energy recently announced up to $18 million in support for 32 projects that it says will advance geothermal energy development in the U.S. The projects target research and development in three areas: advancing subsurface analysis and engineering techniques for enhanced geothermal systems (EGS), applying a mapping approach called “play fairway analysis” to discover new geothermal resources and accelerating extraction technologies to unlock domestic supplies of high-value materials like lithium from low- to moderate-temperature geothermal resources.
These projects are expected to lower the cost and risk of geothermal development and accelerate technological advancement and economical deployment of geothermal energy.
Twelve EGS research and development projects will share $10 million in funding to use techniques such as isotope studies, rock mechanics experiments and tracer studies integrated with geophysical methods to increase the precision and accuracy of measuring underground reservoir properties over time.
EGS are engineered reservoirs where hot rock can be found but where a limited number of pathways exist through which fluid can flow. During EGS development, underground fluid pathways are created and their size and connectivity are increased. These enhanced pathways allow fluid to circulate throughout the hot rock and carry heat to the surface to generate electricity.
Project teams will focus on laboratory feasibility studies to characterize critical EGS reservoir parameters (such as fracture length, fracture aperture, fluid flow pathways, and in-situ stress) to engineer geothermal reservoirs.
Play fairway analysis, a subsurface mapping technique used for oil and gas exploration, helps to pinpoint where geothermal energy resources may lie. Eleven projects will share $4 million in funding to apply this analysis technique to identify prospective geothermal resources in areas with no obvious surface expression by detecting and plotting underground heat, permeability and fluid to discover where all three are most likely to be present together. The resulting maps will serve to quantify and reduce uncertainty for geothermal energy exploration.
Geothermal brine has the potential to contain relatively high concentrations of rare earths and other valuable materials. This third initiative to receive $4 million in Energy Department support focuses on combining power generation with mineral extraction as a path to developing commercially viable, low- to moderate-temperature geothermal resources, while boosting production of materials needed by manufacturers. Nine projects will focus on feasibility studies aimed at better understanding extraction technologies and process economics, assessing the current critical materials resource base and researching and developing extraction methods.