Earthbending Our Energy Future

Water. Earth. Fire. Air. 

Long ago, the four nations lived together in harmony. Then everything changed when the fossil fuel industry attacked. Only the Avatar, master of all four elements, could stop them. 

Though Avatar: The Last Airbender is an animated TV show from the mid-2000s featuring a six-legged flying bison, this holds some truth. Humanity needs to connect with the elements, especially if we’re going to curb the climate crisis. From bending sunlight into solar power, to using wind to spin turbines, nature-based solutions are the future of the clean energy transition. This week Living on Earth guest Phil McKenna considers harnessing another one of these elements: Earth, through the use of geothermal heating and cooling.

It works like this: water pumped below the Earth’s surface is heated by the planet’s internal energy, and pumped back up through wells to heat our homes and businesses. These systems can also be reversed so that during the summer, this water dumps extra heat into the Earth and comes back up cooler for Earth-powered AC. It’s a pretty cool way to harness the Earth’s natural heating and cooling potential with a relatively low environmental impact. 

McKenna got a firsthand look at this process while touring several geothermal sites in the U.S., including the headquarters of Epic Systems in Wisconsin. Epic, a private tech giant, uses geothermal heat pumps to keep its campus buildings warm in the winter. And in the summer, the system becomes a giant air conditioning system. It’s also how Epic cools its onsite data center year-round. Spanning 400 acres, it’s one of the largest geothermal systems in the world. 

So that’s geothermal heating and cooling. But since heat can be turned into energy as well, geothermal can also generate renewable electricity through steam-powered turbines. I was surprised to learn that the U.S. has the most installed geothermal systems in the world, though they only account for 0.4% of our total electricity generation. And we’re not the only country tapping into this renewable energy source – other nations have been doing so for decades, and with great success. Iceland, for example, is a global geothermal pioneer. About 85% of Icelandic homes are heated using geothermal energy, and roughly two thirds of the country’s total primary energy comes from geothermal sources. 

I saw this process in action while studying abroad in Copenhagen, Denmark, in 2024. As part of a class called “Climate, Glaciers, and Human Impact,” we took a week-long trip to Iceland, where we toured a geothermal plant in Ölfus, about 20 miles outside of Reykjavík.

Which explains the smell. Stepping off the tour bus, my classmates and I were immediately greeted by the stench of rotten eggs – not what you’d expect in such a vast, snowy, landscape. This is because magma stored deep underground contains lots of sulfur, so when water runs through these rocks, it releases hydrogen sulfide gas at the surface.

(Photo: Bella Smith)

Of course, Iceland is a rare geological case. This model isn’t feasible everywhere. McKenna reminds us that the high upfront costs of geothermal are one hurdle to implementation in the U.S. Installing a geothermal heat pump system for a single home costs around $27,000 to $30,000, before tax incentives. 

Still, Iceland is a pretty cool case study of what geothermal can achieve when conditions – and investments – align. As we imagine different energy futures in the midst of climate change, geothermal power reminds us to harness the elements and work with nature, not against it. 

Bella Smith

Assistant Producer