Climate Solutions Week: Geothermal

This coverage is made possible through a partnership between IPR and Grist, a nonprofit environmental media organization.

It’s NPR’s 2025 Climate Solutions Week. This year’s topic is “Rethinking Home," bringing us reporting on how our homes and communities can be more resilient and offer solutions to the changing climate.

Throughout the week we’ve been hearing from Sarah Mills, the director of the University of Michigan’s Center for EmPowering Communities, who joined us a few weeks ago to talk through some of the questions listeners sent in. 

Today we’re talking about using the heat within the Earth to produce electricity or heating, known as geothermal energy.

Alan in Traverse City wrote...

...to ask whether there were any plans to use geothermal energy to reduce Michigan's dependence on fossil fuels.

We asked Sarah Mills...

... who told us that she hasn’t heard a lot about building entire geothermal power plants. "However, on the HVAC side, on the home heating and cooling side, absolutely," she said. "It's a really important strategy, actually, to get people off natural gas."  

Electricity and heating

As of 2023, seven states in the country had geothermal power plants, according to the U.S. Energy Information Administration. Geothermal makes up .4% the country’s total utility-scale electricity generation, with most of that coming from California and Nevada.

Like many states, Michigan doesn't have easy access to geothermal energy for power generation, since the high temperatures needed are deeper underground, according to Western Michigan University.

But geothermal systems can be used here as a more efficient way to heat and cool buildings. These are among a variety of heat pumps.

"Typically, we say, kind of ‘electrify everything,'" Mills said. "You can do a heat pump that looks like an air conditioner and operates much like an air conditioner that kind of sits outside. Or you can have geothermal — again, that runs off of electricity, but it uses the differential, the constant temperatures underground, to better heat and cool your home."

Both air- and ground-source heat pumps cut down on planet-warming emissions (even when powered by a grid that runs mainly on fossil fuels). But ground-source heat pumps are even more efficient than their air-source counterparts; according to the Department of Energy, ground-source heat pumps are quieter, can last longer and don't require as much maintenance.

Upfront costs to build geothermal systems can be steep. There are federal tax credits to help people pay for them, although the Trump administration has been working to slash those programs. Some states and utilities offer incentives as well.

Air-source heat pumps make up most of the heat pump market, while ground-source heat pumps are just a small slice. (Overall, air-source heat pumps have outsold gas furnaces in recent years, though that doesn’t necessarily mean people are foregoing gas furnaces, since homes can need multiple heat pumps to replace a gas furnace.)

According to Mills, geothermal is an important option to reduce emissions from heating and cooling systems — one that has a lot of potential. For instance, Consumers Energy is exploring using geothermal energy for some neighborhoods in Michigan. And, Mills said, it's part of the University of Michigan’s strategy to decarbonize: The school just dug a series of geothermal wells for new dorms.

"It's all over campus, like, that's our plan," she said. "Some cities are also looking at geothermal as well. And actually, I just got the email that my kids' middle school in Ann Arbor, they're drilling geothermal wells to provide power for the HVAC in kind of school renovations."