A significant long-term opportunity for widespread power production from geothermal resources lies in enhanced geothermal systems (EGS), where innovative technology development and deployment could provide exponentially more power than existing geothermal technology. EGS projects use human-made reservoirs to capture heat where the subsurface lacks the permeability or fluid saturation found in naturally occurring geothermal systems.
One of the Geothermal Technologies Office’s (GTO) primary objectives is to realize the nation’s full geothermal resource potential through the use of cost-competitive EGS electricity generation. In pursuit of this goal, GTO actively engages in research, development, and demonstration to validate cutting-edge EGS analysis, improve performance, and reduce costs.
The Department of Energy funds several large-scale EGS demonstration projects, currently and in previous years. The data and scientific findings collected from these demonstrations are critical in guiding GTO’s investment in EGS technology.
Current Projects
FORGE
GTO’s largest EGS demonstration initiative is the Frontier Observatory for Research in Geothermal Energy site, or FORGE, in Milford, Utah. Led by the University of Utah, FORGE is a dedicated field site, used to develop, test, and accelerate breakthroughs in EGS technologies and techniques. GTO has also supported a multiple-national-laboratory project to conduct laboratory-scale EGS demonstration research through the EGS Collab initiative. This initiative started in 2014 and as of 2023 is ongoing.
EGS Pilot Demonstrations (Bipartisan Infrastructure Law)
GTO-selected projects under the Bipartisan Infrastructure Law EGS Pilot Demonstrations initiative will provide further advances in EGS technologies in a range of geographic sites with varying geologic conditions. First-round selections in this rolling funding opportunity are anticipated in late 2023.
Past Projects
Location: Bend, Oregon
Partner: AltaRock Energy, Inc.
DOE Funding: $21.4 millionAltaRock's EGS demonstration project at Newberry Volcano near Bend, Oregon, represented a key step in geothermal energy development, demonstrating that an engineered geothermal reservoir can be developed at a greenfield site. Preliminary results from the AltaRock Energy EGS demonstration suggested that the project successfully created three separate zones of fluid flow from a single well where none existed before—a first-of-its-kind achievement. AltaRock completed reservoir stimulation in January 2013.
Newberry marked a critical achievement in options to reduce the cost of geothermal development.
Reports:
Cladouhos, T., et al 2015
Newberry Seismic Deployment Fieldwork Report
Newberry Volcano EGS Demonstration - Phase I Results
Newberry EGS Demonstration Report: Stimulating the Existing Fracture Network (Phase 2.1 Report)
Newberry EGS Demonstration Report: Repairing and Re-stimulating Well 55-29 (Phase 2.2 Report)Location: Middletown, California
Partner: Lawrence Berkeley National Laboratory
DOE Funding: $6 millionThe Geysers represents the nation's first sustained EGS demonstration success, following a year-long stimulation at two previously abandoned geothermal wells along the outer edges of an operating geothermal field. Using cost share from GTO, Calpine Corporation's EGS demonstration in Middletown, California, created a new and distinct reservoir that successfully yielded enough steam to produce 5.8 MW of electricity. Because of existing infrastructure, this EGS reservoir demonstrated that stimulating hot rock on the margins of existing hydrothermal fields can secure higher productivity at low cost.
Location: Churchill County, Nevada
Partner: Ormat Technologies
DOE Funding: $4.5 millionAt the Brady Geothermal Field EGS demonstration site in Nevada, Ormat improved well injectivity to commercial levels and robust hydraulic connection between the well and the producing field in its hydraulic stimulation of the target well using EGS technology. The project's success encouraged future use of EGS well stimulations to improve flow to commercial production levels, yielding clean, domestic, baseload geothermal energy.
Location: Churchill County, Nevada
Partner: Ormat Technologies
DOE Funding: $5.4 millionIn April 2013, as part of the Obama Administration's all-of-the-above energy strategy, DOE recognized the nation's first commercial EGS project to supply electricity to the grid. Leveraging $5.4 million in DOE funding matched by $2.6 million in industry investment, Nevada-based Ormat Technologies increased power output by 38% within an operating geothermal field at Desert Peak, Nevada, generating an additional 1.7 MW of electricity production.
Extending the life of unproductive wells using new technologies is one example of these innovations. With an increased injection rate of up to 1,500 gallons per minute (gpm), the well stimulation at Desert Peak established new revenue, greater resource reserve, and production certainty, which can boost investor confidence. The Desert Peak success demonstrated that EGS technologies are within reach.
Location: Raft River, Idaho
Partner: University of Utah
DOE Funding: $8.6 millionAt the Raft River geothermal field in Idaho, the University of Utah developed and demonstrated techniques to create and sustain EGS reservoirs, including thermal and hydraulic stimulation, with the ultimate goal of improving the overall performance and output of the field. The University of Utah successfully completed well rework operations at U.S. Geothermal's Raft River field in 2012. This set the stage for the thermal and hydraulic stimulation of the target well and ultimately demonstration of the technical viability of EGS technology at this site. The Raft River demonstration contributed to ongoing research into EGS well stimulations to improve the flow characteristics of sub-commercial wells to the levels of commercial production.
More information about efforts to test and demonstrate EGS technologies and techniques is available on GTO’s EGS page and through GTO Peer Review project presentations.