What it takes to unleash the potential of geothermal energy

“Geothermal energy is really ready for prime time,” says Tim Latimer, founder and CEO of startup EGS Fervo.

The attractiveness of geothermal energy lies in its consistency: while the production of electricity from wind and solar power plants varies with the weather and time of day, geothermal energy always works, providing a stable source of electricity.

“This is truly the only renewable baseload source,” says Jody Robins, geothermal engineer at the National Renewable Energy Laboratory. Nuclear energy (carbon-free but non-renewable) can serve a similar role, although its use is limited by cost, waste issues and public opinion.

Modern geothermal power plants have been operating in the United States since the 1970s. These installations typically pump hot water or steam from underground to the surface to move the turbine and generate electricity. The water is then pumped back to maintain pressure underground to keep the process going.

Major geothermal sites share certain characteristics in common: heat, cracked rock and water are all close together and within miles of the surface. But by now the most accessible geothermal resources – in the United States, they are mainly concentrated in the west – have already been developed. While researchers think there are still many potential sites to be found, it is difficult to know where they are. And in much of the eastern United States and many other places around the world, underground rocks are not suitable for traditional plants, or there is no water.

Some researchers and startups are trying to spread geothermal energy to new territories. With the help of EGS, they are trying to engineer what is underground, pumping fluid into impermeable rock to open cracks. This creates a space in which water can move freely and heat up, producing the steam needed to generate energy. This process can provoke earthquakes, as early projects in South Korea and Switzerland showed. However, EGS is similar to hydraulic fracturing, which is widespread in the US, and the risks are likely manageable in most locations, Robins said.

This approach can extend geothermal energy to locations where there is no groundwater or rock required for traditional plants.

However, these resources will not be easy to obtain. Commercial drilling usually does not go much deeper than seven kilometers (four miles) – often even less for cost reasons – and in many places where geothermal energy can be useful, it is not hot enough at this depth to reach 150 ° C. Is necessary for economical power generation. … Reaching a sufficient temperature could mean diving deep, requiring new methods and technologies to withstand high temperature and pressure.

Courtesy of the Department of Geothermal Technology, US Department of Energy.

Fervo is working on some of these details in their own projects, including one announced earlier this year with Google to install geothermal facilities near the company’s data centers in Nevada. He was also recently involved in a Department of Energy project in central Utah called BODY (Frontier Observatory for Geothermal Energy Research).

Academic and industry researchers at FORGE are trying to find best practices for deploying EGS, including drilling and reservoir maintenance. The site was chosen because its geology is representative enough for locations where other EGS plants could be built in the US, says Lauren Boyd, EGS program manager at the Department of Energy’s geothermal technology office.

With new funding from the Infrastructure Bill, the Department of Energy will finance four additional demonstration sites. This will broaden the understanding of researchers about the creation of EGS objects, as they can work in different places and with different types of stones. At least one plant will be built in the eastern United States, where geothermal energy is less common.

But it’s not just technology barriers that have slowed the development of geothermal energy, says Susan Hamm, director of the US Department of Energy’s geothermal technology division. The construction of a geothermal power plant can take up to ten years due to the availability of all the necessary permits. Streamlining this documentation could nearly halve that time and double projected geothermal capacity by 2050.

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