Can Geothermal Power Play a Key Role in the Energy Transition? - 2020

Geothermal Energy / Economics

Robbins opined in late 2020 that geothermal is a renewable energy dream. Heating the 6 million square feet in the geothermally warmed buildings costs about $1,000 a month for the electricity to pump it. (The total annual cost for depreciation, maintenance, personnel, and repair of the city’s district heating system is about $750,000.) “We’re heating 92 of the biggest buildings in the city of Boise,” said Jon Gunnarson, the city’s geothermal coordinator. “The buildings strip heat, collect it, and run it to an injection well. We use it once and reinject it and use it again.”

The Boise district system is how geothermal energy is most often thought of — natural hot water is pumped into radiators or used to generate electricity. It is considered a local phenomenon — few places are sitting on an underground river of steaming hot water — and so geothermal has not been viewed as a major feature on the alternative energy landscape.

Many experts see geothermal power as an essential component of the world’s green-energy future. But a number of experts around the world say that notion is wrong. Thanks especially to the deep-drilling techniques and knowledge about underground formations developed by the oil and gas industry during the fracking boom, a type of geothermal energy called deep geothermal can access hot temperatures in the earth’s mantle as far down as two to three miles. At various depths up to this level, much of the planet contains extremely hot water or there is hot rock into which water can be injected and heated, a technology known as enhanced geothermal systems. In either case, the hot water is pumped out and used to directly heat buildings or to generate electricity with steam or hot water.

“Wherever we are on the surface of the planet, and certainly the continental U.S., if we drill deep enough we can get to high enough temperatures that would work like the Boise system,” said Jefferson Tester, a professor of sustainable energy systems at Cornell University and a leading expert on geothermal energy. “It’s not a question of whether it’s there — it is and it’s significant. It’s a question of getting it out of the ground economically.”

Even though geothermal is barely on the alternative energy radar, the U.S. already produces 3.7 gigawatts (GW) of geothermal electricity, enough to power more than 1 million homes. It’s the world’s leading producer — primarily in central California and western Nevada. California has 43 operating geothermal generating plants, and is about to build two more.

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In a recent report, the International Renewable Energy Agency (IRENA) predicted the output of geothermal in Europe could increase eight-fold by 2050. And a 2019 U.S. Department of Energy (DOE) report — GeoVision: Harnessing the Heat Beneath Our Feet — refers to the “enormous untapped potential for geothermal.” By overcoming technical and financial barriers, the report says, generating electricity through geothermal methods could increase 26-fold by 2050, providing 8.5 percent of the United States’ electricity, as well as direct heat.

“GeoVision models indicate the opportunity for more than 17,500 direct-heating installations as well as heating and cooling for the equivalent of more than 28 million households using geothermal heat pumps by 2050,” wrote Susan Hamm, director of DOE’s Geothermal Technologies office.

Accessing deep geothermal is expensive and risky. But with a global focus on decarbonizing economies, many countries could offer risk-mitigation strategies and financial incentives, including tax benefits, cost sharing, and technical research. The U.S. Department of Energy, for example, has committed $150 million to the Frontier Observatory for Research in Geothermal Energy (FORGE) project in Utah as a study and test site for enhanced geothermal.

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Experts say that governments have to help finance geothermal projects and get involved on the front end to mitigate risk. “Additional incentives have to be set in place,” said Francisco La Camera, director general of the International Renewable Energy Agency, told Thinkgeoenergy.com, an industry website. “It’s crucial that all the risk and the cost of the first phase are taken into account by policy makers to make geothermal more attractive.”

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