Google says a first-of-its-kind geothermal energy project is now feeding carbon-free electricity (CFE) into the Nevada grid that powers its data centers in the area. The company says that the enhanced geothermal system (EGS) is delivering a round-the-clock supply of CFE to the grid. It’s a step toward Google’s goal of entirely powering its data centers and offices on CFE by 2030.
Google teamed up with clean energy startup Fervo Energy in 2021 to work on an EGS. Unlike other sources of CFE such as solar and wind, geothermal projects can operate at any time (solar projects, for instance, can only capture energy during the day).
Fervo Energy achieved a geothermal breakthrough earlier this year when its system achieved flow and power output records for an EGS. It was capable of producing 3.5 megawatts of electricity — enough to power around 2,600 homes. That test result was said to be the first time an energy company proved an EGS is capable of working on a commercial scale.
Scientists have been trying to make an EGS work since the 1970s. A natural geothermal system requires a blend of heat, rock permeability and fluid to generate electricity. In areas where there’s sufficient heat but not enough permeability, an EGS creates the latter by drilling deep into the earth and injecting fluid to create fractures in the rock.
At its Nevada site, Fervo drilled 8,000 feet into the ground, then extended the well horizontally to reach more of the hot reservoir. It drilled a second horizontal well to intersect the fractures in the rock. The company pumps cold water from the first well through the fractures into the second well. The water absorbs heat from the surrounding rock. This is used to generate steam and that produces CFE.
The Department of Energy has acknowledged that, unlike with gas and oil fracking, EGS poses a low risk of water contamination. EGS reservoirs are typically much deeper in the ground than oil and gas reservoirs and aren’t close to groundwater or near-surface drinking water supplies. Geothermal power plants don’t release any water on the surface either.
A 2019 report by the DOE found that — through advancements in technology as well as in policy and procurement — EGS could generate up to 120 gigawatts of clean energy by 2050. That would be enough to cover over 16 percent of the US’ expected electricity needs.
Google says it’s working to accelerate adoption of EGS as a clean energy solution. To that end, it recently teamed up with Project InnerSpace, a non-profit organization that’s focused on removing barriers that are limiting the global development of geothermal energy. Fervo, meanwhile, is building an EGS site in Utah that it expects to deliver 400 megawatts of 24/7 carbon-free electricity — enough to power as many as 300,000 homes. Fervo says that site will start delivering power to the grid in 2026 and reach full-scale production two years later.