In a sagebrush valley full of wind turbines and solar panels in western Utah, Tim Latimer gazed up at a very different device he believes could be just as powerful for fighting climate change — maybe even more. It was a drilling rig, of all things, transplanted from the oil fields of North Dakota. But the softly whirring rig wasn’t searching for fossil fuels. It was drilling for heat.

Mr. Latimer’s company, Fervo Energy, is part of an ambitious effort to unlock vast amounts of geothermal energy from Earth’s hot interior, a source of renewable power that could help displace fossil fuels that are dangerously warming the planet.

“There’s a virtually unlimited resource down there if we can get at it,” said Mr. Latimer. “Geothermal doesn’t use much land, it doesn’t produce emissions, it can complement wind and solar power. Everyone who looks into it gets obsessed with it.”

Traditional geothermal plants, which have existed for decades, work by tapping natural hot water reservoirs underground to power turbines that can generate electricity 24 hours a day. Few sites have the right conditions for this, however, so geothermal only produces 0.4 percent of America’s electricity currently.

Dozens of geothermal companies have emerged with ideas. Fervo is using fracking techniques — similar to those used for oil and gas — to crack open dry, hot rock and inject water into the fractures, creating artificial geothermal reservoirs. Eavor, a Canadian start-up, is building large underground radiators with drilling methods pioneered in Alberta’s oil sands. Others dream of using plasma or energy waves to drill even deeper and tap “superhot” temperatures that could cleanly power thousands of coal-fired power plants by substituting steam for coal.

Still, obstacles to geothermal expansion loom. Investors are wary of the cost and risks of novel geothermal projects. Some worry about water use or earthquakes from drilling. Permitting is difficult. And geothermal gets less federal support than other technologies.

In a sagebrush valley full of wind turbines and solar panels in western Utah, Tim Latimer gazed up at a very different device he believes could be just as powerful for fighting climate change — maybe even more. It was a drilling rig, of all things, transplanted from the oil fields of North Dakota. But the softly whirring rig wasn’t searching for fossil fuels. It was drilling for heat.

Mr. Latimer’s company, Fervo Energy, is part of an ambitious effort to unlock vast amounts of geothermal energy from Earth’s hot interior, a source of renewable power that could help displace fossil fuels that are dangerously warming the planet.

“There’s a virtually unlimited resource down there if we can get at it,” said Mr. Latimer. “Geothermal doesn’t use much land, it doesn’t produce emissions, it can complement wind and solar power. Everyone who looks into it gets obsessed with it.”