Until relatively recently, harnessing geothermal energy in the US to meet power production and heating needs has been largely restricted to the western states.
The first geothermal production wells in this country were drilled in The Geysers, California, and much of the development since that time has similarly taken place in the west. As of 2021, the states of California and Nevada (combined) accounted for 85% of the country’s geothermal power plants and 93% of the installed capacity, with no geothermal plants being located any further east than New Mexico.
The reason for this is that exploiting geothermal energy in the conventional manner requires a very specific setting. Heat, fluid, and rock permeability must all be in abundance to utilize the Earth’s thermal energy. The western states’ geologic setting to the Pacific Ring of Fire results in several such locations.
However, advances in technology are opening opportunities in other parts of the country as well. Technological developments impacting geothermal include enhanced/engineered geothermal systems (EGS), closed-loop or advanced geothermal systems (AGS), and thermal energy networks (TENs).
Enhanced Geothermal Systems
EGS aren’t a new concept. The belief that areas with sufficient heat and moisture but lacking appropriate permeability could be engineered into viable geothermal reservoirs has been discussed for years, but recent developments are making this a reality.
In 2023, Fervo Energy announced a milestone in EGS development when a 30-day well test at their Project Red commercial pilot site demonstrated a flow rate of 63 L/sec at high temperature that enables 3.5 MW of electric production, setting records for both flow and output from an EGS.
The well test circulated fluid through the doublet system by pumping fluid down an injection well, through a fractured reservoir system, and up a production well. The injection pump located on the well pad provided all the pressure to drive fluid through the system with no need for a downhole pump or artificial lift system.
Sage Geosystems Inc. recently announced that it will partner with San Miguel Electric Cooperative Inc. to build the first geopressured geothermal system. The 3-MW EarthStore system will utilize the Earth's natural capacity for energy storage to produce dispatchable electricity on demand. Sage will operate as a merchant, buying electricity when production is plentiful, then storing it and selling back to the grid during periods of shortage. The facility, located in Christine, Texas, will use Sage’s proprietary technology to store energy, with a target storage duration of from 6 to 10 hours.
Utah's Frontier Observatory for Research in Geothermal Energy (FORGE) is an international field laboratory dedicated to developing and testing the methods and techniques required to create, sustain, and monitor enhanced geothermal systems resources. It is managed by the Energy & Geoscience Institute at The University of Utah and funded by the US Department of Energy. The project recently achieved a major breakthrough for the industry when circulation tests proved fluid flow and energy transfer from an EGS reservoir in hot, dry granite.
Advanced Geothermal Systems
AGS are closed-loop systems that don’t require a constant source of water. These systems circulate a manmade fluid through a sealed piping system to absorb through conduction and transport the heated fluid to the surface. After driving a turbine to produce power, the cooled liquid is cycled through the closed-loop piping system to be reheated. There is no direct interaction between the subsurface environment and the liquid in the pipes.
One company helping advance this approach is Canadian-based Eavor, whose Eavor-Loop technology utilizes a closed system that circulates a proprietary working fluid, thus limiting the need for accessibly fluids and rock permeability in the site. In 2023, the company celebrated the inauguration of their first commercial project in Geretsried, Germany, which targets 8.2 MW of power by 2026.
AGS are also being used to extend the lifespan and increase the production in existing geothermal wells. GreenFire Energy recently announced a project to demonstrate their GreenLoop system at The Geysers geothermal field in northern California. The Geysers was the first geothermal field in the US used to produce electricity and is among the largest developed geothermal fields in the world, but it has experienced a decline in production over the years. GreenFire’s closed-loop system uses a downhole tube-in-tube heat exchanger to circulate a variety of working fluids, creating a system that extracts heat rather than water, thereby preserving the resource.
Thermal Energy Networks
While not as geologically limited as conventional geothermal power production, geothermal district heating systems have also traditionally been focused in the western states, beginning well over a century ago in Boise, Idaho,
TENs are utility-scale thermal energy infrastructure projects that connect multiple buildings into a shared network involving thermal energy sources such as geothermal boreholes, surface water, and wastewater. They operate at lower temperature differentials compared to traditional district heating systems, giving them a variety of advantages, including lower heat losses, flexible heat sources, energy storage compatibility, and reduced infrastructure costs.
At least 13 states are currently implementing TENs, including East Coast states such as New York, New Jersey, and Massachusetts. Most of these projects are still in the planning or regulatory stage, but construction has already begun in a few places. The first geothermal network pilot project in the US began construction in 2022. Located in Framingham, Massachusetts, the route consists of 36 buildings (24 residential and five commercial) and a total of 125 customer accounts.
Expanding Geothermal Market
The geographic expansion of possible geothermal project locations opens up the possibility of dramatically increased investment in the industry. A 2024 Wood Mackenzie article estimates that though global spending on geothermal pilot projects is currently limited to a few hundred million USD, it could rise to as much as $1 trillion by 2050 if these next-generation technologies succeed in making geothermal development location-agnostic.
This increased investment is, to some degree, already being seen. At least six startups have closed significant funding rounds this year. The focus of these companies varies—from developing new drilling methods to improving well designs to using artificial intelligence (AI) to reduce exploration costs. But the complementary nature of these goals makes the sector as a whole more attractive to potential investors.
In addition to the exploration and development companies, there are also a variety of service, technology, and equipment design companies among the recent geothermal startups. Some of the services offered include reservoir stimulation, HVAC system installation, and advanced AI sensing techniques. Tool and equipment companies have focused on aspects such as improved drilling technology, subsurface monitoring tools, and software development.
Texas seems to be a nexus of geothermal startups. According to a 2023 report, titled “The Future of Geothermal in Texas: The Coming Century of Growth & Prosperity in the Lone Star State,” from 2016 to 2022, 11 of the 27 geothermal-related startups in the US were headquartered in Texas. Of the 43 total startups polled for the report, 39% were engaged with AGS technology, 23% were engaged with EGS, and 15% were pursuing either both or hybrid concepts. Only 23% were not involved with either technology. The same poll showed 31% of the startups focused on power production, 23% pursuing direct-use heat applications, and another 23% engaged with both.
Moving Forward (and Eastward)
For the bulk of its history, the geothermal industry in the US has been constrained by its geographic limitations. But new technologies are breaking down these limitations and seem to be creating the right set of circumstances for expansion into the rest of the country, and indeed, the world.
Overcoming the geographic requirements of geothermal production could be game-changing for the industry, as well as the energy sector as a whole. TENs are already bringing geothermal heating and cooling to the Midwest and East Coast, while EGS and AGS technologies point toward the possibility of geothermal power production anywhere.
As states wrestle with how to meet their Renewable Portfolio Standards, geothermal offers the highest capacity factor among renewable sources, as well as a competitive Levelized Cost of Electricity (LCOE). It also offers a small surface land footprint, near-zero emissions, and the flexibility to ramp up or down to help cover changing operational requirements through the day as the output of intermittent renewables varies.
Geothermal power, heating, and cooling coming soon—to a state near you.
Brian Schmidt is a seasoned librarian and industry analyst based in Davis, California, with more than a decade of experience supporting information needs in diverse settings. Since 2011, he has served as librarian and industry analyst for Geothermal Rising. Previously, Brian served in a variety of library and research related roles, including reference librarian and archivist. He is one of the authors of the 2021 U.S. Geothermal Power Production and District Heating Market Report as well as the follow up report, which is currently in development. He earned a BA in psychology from the University of California, Berkeley, an MA in philosophy and religion from the California Institute of Integral Studies, and an MLIS from the University of Wisconsin-Milwaukee.
Anine Pedersen is currently the director of science and external affairs at Geothermal Rising. Prior to this, Anine held positions as a senior exploration geologist at Criterion Energy Partners, as well as a team lead and geographic information systems technician while contracted to Apple Inc. Anine also has extensive experience as a geologist at Anadarko Petroleum Corporation, where she worked on various exploration projects in eastern Canada, West Africa, and East Africa. Anine's academic background includes a BS in geology and Earth science and an MS in geosciences from The University of Texas at Austin.