Bill Gates’s $1 billion clean energy fund just opened up its checkbook for the first time. Breakthrough Energy Ventures will announce today it’s investing in a host of startups developing technology that can confront the growing dangers of climate change.

Among the first selected was a startup in Berkeley, California, that is applying fracking techniques to the geothermal industry in the hope of converting far more of the planet’s latent heat into a source of clean energy.

If Fervo Energy’s technologies work as intended, they could enable existing geothermal sites to boost electricity production, or allow entirely new areas to tap into heat within the earth’s crust. Increasing geothermal generation could ease the broader shift to cleaner energy systems, because it can provide always-on power or ramp-up as needed, unlike variable wind and solar farms.

The other businesses on Breakthrough’s inaugural list of portfolio companies, first reported by Quartz early Wednesday and now posted on Breakthrough’s site, include grid-storage startup Form Energy; solid-state battery company QuantumScape; MIT’s fusion spinout Commonwealth Fusion Systems; biofuels firm DMC Biotechnologies; Pivot Bio, which is developing replacements for nitrogen fertilizer; CarbonCure, which is storing carbon dioxide in concrete; Quidnet, which makes subsurface pumped hydro storage; and Zero Mass Water, which created technology to pull water from air.

The investment amounts haven’t been disclosed.

Fervo CEO Tim Latimer, who previously worked as a drilling engineer for BHP Billiton’s shale operations, says the startup intends to use the funding to move forward with field deployments to test and refine their so-called enhanced geothermal systems. The company’s other cofounder is Jack Norbeck, who was a reservoir engineer at The Geysers in Northern California, the world’s largest geothermal field.

Geothermal energy takes advantage of heat naturally generated under the earth’s crust, which warms underground reservoirs. This water works its way toward the surface, in liquid and gas form, through a network of porous rocks and fractures. Geothermal plants use deep wells to tap into that steam, leveraging it to drive turbines and generate electricity.

But geothermal generally works only in regions with the perfect combination of underground heat, fluid, and adequately permeable rocks. Many places meet the first two conditions but not the last one.

For decades now, scientists have been exploring the potential of enhanced geothermal techniques to increase underground permeability, generally by pumping water through an artificial well to widen existing fractures. To date, however, results have been mixed.

An earlier MIT study concluded that modest federal investments into research and development in this area could add more than 100 gigawatts of new generating capacity for clean energy in the United States within 50 years—or the equivalent of about 50 Hoover Dams.

Fervo’s founders—currently fellows at the Cyclotron Road program at Lawrence Berkeley National Laboratory—believe they can improve the performance of enhanced geothermal systems by isolating multiple zones inside a well and optimizing water flow within each of them.

While some of the technical details are proprietary, Latimer says the company is using horizontal drilling techniques that have become far cheaper, thanks to improvements developed by the booming natural-gas industry. It is also employing fiber-optic temperature gauges that can run through underground wells, along with other sensors and simulation software, to create a clearer understanding of underground structures and dynamics.

Enhanced geothermal systems, however, do raise risks and concerns. Critics fear the process may contaminate drinking water and generate earthquakes, much as fracking and subsequent waste water injection have.

Geopower Basel’s enhanced geothermal project in Basel, Switzerland, was famously halted around a decade ago following a series of earthquakes. In addition, geothermal AltaRock Energy scrapped a demonstration project at The Geysers in 2009 after confronting technical challenges and public concerns over potential seismic dangers.

“As with any project, there are inherent risks that we need to manage for,” Latimer says. “But we know a lot more about the subsurface networks now than we did in years past, and we can apply these lessons to make sure we develop systems safely and effectively.”