What it takes to unravel the potential of geothermal energy

“Geothermal is really ready for prime time,” said Tim Latimer, founder and CEO of EGS Startup Forvo.

The application of geothermal is all compatible: wind and solar plant power output varies with weather and time of day, geothermal power is always on, providing a stable source of electricity.

“It’s really the only baseload renewable,” said Jodie Robbins, a geothermal engineer at the National Renewable Energy Laboratory. Nuclear power (which is carbon-free but not renewable) could play a similar role, although costs, waste issues, and public perception have limited its deployment.

Modern geothermal power plants have been operating in the United States since the 1970s. These plants typically pump hot water or steam from the ground to the surface to move turbines and generate electricity. The water is then pumped again to maintain the groundwater pressure, so the process can continue.

Prime geothermal sites share certain characteristics: heat, rock and water with cracks in it, everything close to each other and within a few miles of the surface. But by far the most readily available geothermal resources – in the United States, they are largely concentrated in the west – have been tapped. Although researchers believe that many more potential sites have not yet been found, it is difficult to determine where they are. And in most parts of the eastern United States and in many other parts of the world, underground rock is not the right kind of work for traditional plants, or there is no water.

Some researchers and startups are trying to expand geothermal to new places. With the help of EGS, they are trying to engineer what is underground by pumping liquid into impermeable rocks to force cracks to open. This creates a space where the water is free to move around and heat up, creating the steam needed for energy. Preliminary projects in South Korea and Switzerland have shown that the process is prone to earthquakes. However, like EGS fracking, which is widespread across the United States, and the risks are probably manageable in most places, Robbins says.

This method can expand geothermal in places where there is no groundwater or rock type required for conventional vegetation.

However, access to these resources will not be easy. Commercial drilling typically does not go deeper than seven kilometers (four miles) কারণে because of the cost, it is often less than that — and many places that can benefit from geothermal are not hot enough to reach a depth of 150 degrees Celsius economically for power generation. . Reaching adequate temperatures can mean going deeper, which will require new techniques and technologies that can withstand high temperatures and pressures.

Courtesy DOE Geothermal Technology Office

Farvo is working on some of those details in its own projects, one of which was announced earlier this year with Google to install geothermal power near the company’s data center in Nevada. It was recently involved in a DOE project in central Utah called FORGE (Border Observatory for Geothermal Energy Research).

Academic and industry researchers at FORGE are working to find the best practices for setting up EGS, including drilling and reservoir maintenance. The site was chosen because its geology roughly represents the United States where other EGS plants could be built, said Lauren Boyd, EGS program manager at the DOE’s Geothermal Technology Office.

With new funding from the infrastructure bill, the DOE will fund four additional demonstration sites. This will further broaden what researchers understand about the installation of EGS facilities, as they will be able to work in different places and with different types of rocks. At least one plant will be built in the eastern United States, where geothermal is less common.

But it is not the technological barriers that have slowed the progress of geothermal energy, says Susan Hamm, director of the DOE’s Geothermal Technology Office. It can take a decade to build a geothermal plant because all the permits are involved. If that paper is streamlined, that time will be cut in half and the projected geothermal capacity will double by 2050.

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