A reduction in carbon-emitting coal plants has increased reliance on natural gas, especially in colder climates like Minnesota. But natural gas is still a major source of greenhouse gas emissions, so the city Minneapolis is beginning to eye aquifer thermal energy as a cleaner alternative.

The technology uses groundwater to heat and cool buildings and is planned for four buildings in the upcoming Towerside Innovation District along University Avenue in the Prospect Park neighborhood of Minneapolis.

“But the capacity of the system is fairly limitless, so once its infrastructure is in place, all new development in that area would have the potential to connect,” said Nina Axelson, vice president of sustainability and outreach for Ever-Green Energy, an energy nonprofit partnering on the project.

Axelson said the system draws heat from buildings during warmer months and stores that energy in the aquifer beneath the building. In the colder months, that energy combined with the aquifer’s natural temperature act as a jump start for electric pumps that heat the building.

“It wouldn't be able to [heat the building] alone,” she said. “So this is under the trend of beneficial electrification, which means you're going to pair electricity with that geothermal capacity in the aquifer to increase the heat enough to be used for heating the building or for hot water uses.”

And as the grid increasingly taps renewable energy, the electricity paired with the groundwater system is also increasingly clean.

Axelson said Minnesota’s geology is a good match for the technology, which is more widely used in Europe, and she expects it to become more common in the state. She said three other developments in the region considering aquifer thermal energy.

“This is absolutely a place for Minnesota to lead,” Axelson said.