A first-of-its kind project is tapping energy beneath the ground to heat and cool homes

Heating and cooling heavily relies on planet-warming fossil fuels. But some energy companies are looking to an unlimited thermal energy source below their feet as a clean alternative.

​ Heating and cooling heavily relies on planet-warming fossil fuels. But some energy companies are looking to an unlimited thermal energy source below their feet as a clean alternative. Read More Breaking News, Latest News and Videos | CNN