By the time the Department of Energy (DOE) unveiled the fourth leg of its Energy Earthshot Initiative last year, a project in south-central Utah had long been exploring the potential of geothermal energy in the United States. The Utah Frontier Observatory for Research in Geothermal Energy, otherwise known as Utah FORGE, is an underground field laboratory specifically focused on an emerging field of research and development: enhanced geothermal systems (EGS). But without additional funding beyond 2024, a window of opportunity for developing geothermal energy in the US could run out when Utah FORGE’s wells get plugged.
The idea of EGS is to extract energy in the form of steam heat from the Earth’s interior, not unlike what naturally occurs at geysers or hot springs. While these conventional geothermal systems occur naturally in some parts of the country, EGS provides an opportunity to expand geothermal’s potential across the U.S., even in places where it would otherwise not occur.
“The U.S. has tremendous unrealized geothermal potential,” said Dr. Joseph Moore, principal investigator at Utah FORGE during a recent Heat Beneath Our Feet webinar. “But you can’t meet the US objective of 60,000 megawatts or reducing the cost of EGS using conventional hot spring systems. They’re just not big enough. We need to be able to drill everywhere across the country and we know that if we drill deep enough, we can always find the heat we’re looking for.”
Drilling, however, can come with risks. It can inadvertently cause earthquakes, and not all subterranean topography is suitable for an EGS to be economically efficient.
In order for any geothermal system to be possible, three elements are needed: heat, fluid and permeable rock. When all three elements occur naturally, like they do in much of Utah, Nevada and the Mountain West, conventional systems like geysers or hot springs can form. When water is present as far as four miles below the Earth’s surface, it becomes naturally heated from the rock found at these depths. Then with the appropriate amount of pressure, this heated water propels upward through cracks toward the surface before being released in the form of steam.
While heat is an omnipresent resource underneath the Earth’s surface, two of the other key elements are often still missing: fluid and permeability.
“Temperatures suitable for electric generation are about 300 [Fahrenheit] and can be found across the country at depths between two and four miles,” Dr. Moore said. “However, in most places, the rocks at these depths lack the permeability that is required for natural circulation of water and heat extraction.”
But that’s where an EGS, like the Utah FORGE project, is exploring a solution.
“EGS requires at least two wells, an injection well and a production well,” said Dr. Moore. “Water is injected into the injection well, and we create fractures between the injection and production well. Then [the water is] pumped out of the production well, cooled and recirculated. Unlike an oil and gas system, where the water is removed and injected elsewhere, we circulate the water and so it’s constantly being recirculated into the ground and back into the reservoir.”
As such, an EGS can simply be described as a man-made reservoir underneath the Earth’s surface. When water from the injection well causes pre-existing fractures in the rock to re-open, permeability is created. The injected fluid becomes naturally heated by the internal temperatures of the Earth, before the combination of heat and pressure forces it back to the surface through the production well in the form of steam, functioning like a geyser or hot spring.
At a geothermal power plant, this steam is directed into a turbine that powers a generator, creating electricity. By harnessing this process, the DOE estimates that EGS could reliably power over 40 million homes nationwide, without the need for battery storage typically required with other, more transient renewable resources like solar and wind.
Another unique component of geothermal energy, one that sets it apart from other renewables, is the relative efficiency it provides.
“The U.S. currently produces about 3,700 megawatts of electricity, [while] DOE has set a goal of 60,000 megawatts of electric energy by 2050,” said Dr. Moore. “If you have to use one megawatt per 1,000 homes, you can see how much energy that really is; so to go from 3,700 megawatts to 60,000 megawatts in the next 30 years is going to be very difficult.”
That’s why through its Enhanced Geothermal Shot, the DOE is seeking to reduce the cost of EGS by 90%, to $45 per megawatt hour by 2035. Utah FORGE, a project conducted in partnership with the University of Utah, is funded by the DOE as a critical part of reaching that objective.
While the potential for geothermal is great, Dr. Moore says the technology to utilize it is still developing. Tools melt due to the high temperatures and power plants have had limited economic success.
“Fifteen different projects have been attempted throughout the world, but none have produced [at] a ‘commercial scale,’ that means a system that is producing more than a few megawatts,” Dr. Moore said.
While it’s not impossible to overcome these challenges and scale the level of geothermal energy production to meet the country’s overall climate goals, high volumes of water must be pumped through the system’s wells. This can be a significant challenge for arid states like Utah or Nevada. But that’s also why the Milford location in south-central Utah was selected as an ideal site for the FORGE project.
“There’s no endangered species. There’s no sage grouse here, prairie dogs [and that] makes it easy to work, basically year round,” Dr. Moore said. “You can see there’s no human activity here and there’s no grazing and no crop circles. The reason that that’s the case is no potable water, so that the natural groundwater has relatively high concentrations of minerals that are toxic. So, the state does not allow the water to be used for grazing, for human consumption, for agriculture, and we as Utah FORGE have leased that water.”
But as a publicly-funded project undertaking an expensive field of research, financial resources to keep the plant operational are not unlimited.
“This is a field-scale laboratory and in fact, it’s the only one in the world where tools and technologies for de-risking enhanced geothermal systems can be tested,” Dr. Moore said. “But one of the major problems we face is there is no incentive for industry to build tools. We don’t have an EGS system that is working, for companies to spend their time building tools and spending millions of dollars, so that debt becomes a critical effort.”
As it stands today, the Utah FORGE project is funded by the DOE at $220 million through mid-2024.
“That sounds like a tremendous amount of money, but 50% of the funds are obligated for project management and operations,” said Dr. Moore. “Wells cost between five and $15 million and we have six of them already. Drilled stimulations are five to $10 million. Then 50% of the funding is used to competitively bid R&D projects and currently we’re funding 17 of them at $50 million. So, the money doesn’t go as far as you might think.”
Despite the high costs related to EGS research and development projects, Dr. Moore stresses the vital role geothermal energy can have in meeting clean energy goals and how a project like Utah FORGE is critical to moving the entire industry forward.
“[Utah FORGE] is an essential stepping stone to commercial large-scale EGS development,” said Dr. Moore. “It is being used to develop the roadmap so that developers can take the roadmap and build the system. It also is important to realize, worldwide, there is no other field-scale EGS facility for research.”
Now at the start of 2023, however, Dr. Moore and his team at Utah FORGE are now facing an approaching deadline to achieve the remainder of their objectives. Negotiations with the DOE are ongoing, with hopes that the project can be extended to 2032.
“At the end of 2024, I’m required by the owners of land to plug and abandon the wells and regrade,” said Dr. Moore. “Unless we have continued support for this, it’s going to disappear and we will not have achieved the objective of demonstrating the creation of an EGS.”
The episode featuring Dr. Moore and the Utah FORGE project came as part of the Western Governors’ Association’s Heat Beneath Our Feet webinar series, an initiative aimed at exploring opportunities and challenges related to maximizing the potential of geothermal energy found in many western states.
Scott King writes about science and the environment for the Sierra Nevada Ally. He has a Master’s degree in Media Innovation from the University of Nevada, Reno, and a Bachelor’s degree in Professional Writing with a minor in Marketing from Capital University in Columbus, Ohio. Scott served for two years as a literacy instructor with the Peace Corps in the community of Gouyave, Grenada. Support his work.
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