Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall. 

We’ve used the Earth’s heat as an industrial energy source for over a century, but geothermal power only plays a minor role in our energy grid. Why? And is that about to change? 

Here to tell us more are Charlie Adams and Albert Wu from our Possibly Team.

Charlie Adams: Hi, Megan!

Albert Wu: Hey Megan! 

Megan Hall: When I hear “geothermal” I think Old Faithful and Icelandic hot springs, is that right?

Charlie Adams: Right. Geothermal energy comes from reservoirs of hot water below the Earth’s surface. 

There’s lots of it and not just in Yellowstone and Iceland.

Joseph Moore: if we took even 2% of the energy stored within the shallow crust, that would be more than 2000 times the energy we use annually.”

Albert Wu: That’s Joseph Moore, a research professor at the University of Utah’s Energy and Geosciences Institute.

Charlie Adams: He says, one of the best parts about geothermal is it can produce renewable 24-7 power without burning fossil fuels.

Megan Hall: Wait, how do you get electricity from heat underground?

Albert Wu: There are a few ways. But a typical geothermal power plant drills a mile or two underground to access reservoirs of hot water and pulls them to the surface.

Charlie Adams: As the super hot water rises and experiences lower pressure, it turns to steam, which can spin a turbine to make electricity– just like other power plants!

Megan Hall: Interesting! So how much power do we get from geothermal?

Albert Wu: Right now the U.S. has 64 plants that make up 0.4% of our total electricity generation.

Megan Hall: Why so little?

Charlie Adams: Exploration, drilling, and equipment costs are high compared to other renewables. 

Albert Wu: Also, outside of the Southwest, it’s hard to find the right mix of heat close to the surface, water reservoirs, and the right type of rocks for drilling.

Charlie Adams: But advances in technology may be changing this.

Megan Hall: How?

Albert Wu: Enhanced Geothermal Systems or EGS technology is attracting lots of attention right now.

Charlie Adams: EGS creates human-made underground fracture networks and reservoirs in places where geothermal isn’t usually possible. According to Joseph

Joseph Moore: Enhanced geothermal systems can be developed anywhere in the world.

Megan Hall: How does the process work?

Albert Wu: Some of these breakthroughs have come from using fracking technology. 

Megan Hall: Wait, fracking? That sounds like a problem.

Charlie Adams: While the concept is the same, EGS avoids many of the pitfalls of fracking because oil and gas aren’t involved so they don’t contaminate surface water or soil. 

Albert Wu: To learn more about the differences we spoke with Jeff Tester, a professor of Sustainable Energy Systems at Cornell University.

Charlie Adams: He says a key difference is that when you’re fracking for fossil fuels, water from the underground system has to be removed and then treated at a separate location. 

Albert Wu: That contaminated water can be disastrous if it spills, and reinjecting underground water has caused earthquakes. 

Jeff Tester: but that is not the way in which geothermal operates because there, water is your friend not your enemy, you’re trying to circulate water through the system.

Megan Hall: So, because geothermal circulates water, and doesn’t have to dispose of lots of contaminated water, it’s less likely to have nasty environmental side effects?

Albert Wu: In theory yes, but Tester says it’s still important to monitor it. This is a relatively new process, so there could be unanticipated consequences.

Megan Hall: Got it. So how does the future look for enhanced geothermal systems? 

Charlie: Things are looking up. The Department of Energy has invested tens of millions of dollars in EGS.

Albert Wu: They say EGS could unlock enough energy to power 67 million homes by 2050! 

Charlie Adams: Despite all this, geothermal faces similar hurdles as other renewable energies. There's a long road ahead. 

Albert Wu: It’s unlikely geothermal will become a major source of energy in the US any time soon, but it is set to play an important role in our efforts to transition away from fossil fuels.

Megan Hall: Great! Thanks, Charlie and Albert! 

That’s it for today. For more information, or to ask a question about the way your choices affect our planet, go to the public’s radio dot org slash possibly. Or subscribe to us wherever you get your podcasts. 

Possibly is a co-production of The Public’s Radio and Brown University’s Institute for Environment and Society and Climate Solutions Initiative.