A relatively untapped domestic energy resource, geothermal represents a clean and nearly inexhaustible energy source. The current U.S. installed capacity is 3.4 gigawatts (GW), with vast additional potential: a mean estimated 30 GW of new undiscovered hydrothermal resources and 100+ GW of new geothermal energy accessible through Enhanced Geothermal Systems (EGS). The mission of the Geothermal Technologies Office (GTO) is to accelerate the deployment of domestic electricity generation from geothermal resources by investing in transformative research, development, and demonstration-scale projects that will catalyze commercial adoption. Successful efforts will promote a stronger, more productive economy; provide valuable, stable, and secure renewable energy to power the U.S.; and support a cleaner environment.
The U.S. Department of Energy is providing vouchers to small businesses for products that harness energy from within the earth in the following opportunity areas:
Enhanced Geothermal Systems
Enhanced Geothermal Systems (EGS) are engineered reservoirs, created where there is hot rock but little to no natural permeability or fluid saturation present in the subsurface. In the long term, EGS success would enable the utilization of an enormous, geographically diverse energy resource on the order of 100+ GW. To make this possibility a reality, the SBV Pilot is poised to help small businesses pursue innovative technical solutions through collaborative research, supported by demonstration and testing programs already underway, as appropriate.
Critical to advancing EGS are technologies that facilitate characterization of local stress, chemical constituents, and fluid and thermal pathways evolution through time. Economic access to the subsurface thermal resource, while ensuring wellbore integrity over multi-decadal timeframes, is another challenge. A final overarching hurdle is sustainable operation, which involves achieving sufficient productivity for commercial EGS power generation without excessive pressure build up or localization and decrease of flow.
Areas of emphasis for EGS include:
- Reservoir characterization, including coupled imaging, drilling for interrogation and monitoring, high-temperature tools and sensors
- Reservoir creation, including formation access, fracture characterization, zonal isolation, permeability enhancement technologies
- Reservoir sustainability, including long-term testing, monitoring, and operational feedback
- Improving the fundamental understanding of the key mechanisms controlling coupled thermo-mechanical-chemical-hydrologic processes at depth
- Gaining a critical and detailed knowledge of fracture mechanics and heat transfer in low permeability rock formations
- Continuous real-time monitoring of microseismic activity and other geophysical and geochemical signatures.
Also of interest are vouchers for R&D that could feed into the operations of the Frontier Observatory for Research in Geothermal Energy (FORGE) such that new technologies are properly positioned for field testing at the site.
Specifically not of interest are vouchers focused on using CO2 as a geothermal working fluid.
Geothermal Systems Analysis
Systems Analysis identifies and addresses barriers to geothermal adoption in the U.S., and validates and assesses technical progress across the geothermal sector. By evaluating trends, conducting impact analyses, identifying best practices, and providing resources and tools, the results from vouchers in Systems Analysis should reduce costs and risk for geothermal developers.
Types of analysis of interest include:
- Environmental impacts, including water resource assessments
- Policy and regulatory barriers to development and deployment, including projects that remove deployment barriers
- Economic modeling and validation of geothermal technologies
- Collecting and disseminating data for public use to spur geothermal development
- Analysis that support EGS, Hydrothermal, and Low Temperature and Coproduced Resources subprograms
- Educational activities.
Low Temperature and Coproduced Geothermal Resources
Low temperature geothermal resources, those with a temperature below 300°F (150°C), have a lower power conversion efficiency than other geothermal resources, but they are abundant, highly accessible across the U.S., and as in the case of co-produced fluids, have much of the necessary infrastructure in place; attributes that lower the costs of geothermal energy production. Improving the efficiency of lower temperature geothermal systems and expanding their utility through value-added commercial opportunities (i.e., Mineral Recovery, Desalination) can enable near-term development of innovative geothermal technologies in more geographically diverse areas of the U.S.
Areas of emphasis for Low Temperature include:
- Mineral recovery, which is a potential value-added pathway to improve low-temperature geothermal system project economics. By developing additional revenue streams from geothermal brines, the economic viability of geothermal projects will increase, concurrently expanding the geothermal energy's potential geographic distribution
- Geothermal direct use, that harvests the heat from geothermal brines and uses it to directly heat (or cool) buildings, as well as for other beneficial thermal processes
- Thermal desalination technologies, which can promote are the expansion of the geothermal market through the development of technologies that can treat brines or produced fluids
- Innovative energy conversion, additional revenue-stream creation, and further advancement of both traditional and newly developed power cycles. Specific developments in this area could include renewable power hybrid cycles, compressed air energy storage (CAES) in conjunction with geothermal power generation, and power system improvements, with the goal of steadily increasing the value of geothermal resources.