Seasonal Underground Energy Storage in Twin Cities

"Researchers drilling under a college campus in the 1980s paved the way for an ambitious new project in the Twin Cities."

"ST. PAUL, Minn. — Nearly half a century ago, the U.S. Department of Energy launched a clean energy experiment beneath the University of Minnesota with a simple goal: storing hot water for months at a time in an aquifer several hundred feet below ground.

The idea of the so-called seasonal thermal energy storage was to tuck away excess heat produced in summer, then use it in the winter to warm buildings.

Now, 45 years after the first test wells were drilled under the university’s St. Paul campus, one of the first large-scale aquifer thermal energy systems in the nation is being built less than 10 miles from the original test site.

The Heights, a mixed-use development rising from a former golf course on the city’s Greater East Side, will tap thermal energy from an aquifer 350 to 500 feet below ground. Groundwater drawn from wells spread across the northern half of the 112-acre development, coupled with high-efficiency electric heat pumps powered in part by solar panels, will provide low-cost heating and cooling with little to no greenhouse gas emissions for 850  homes and several light-industrial buildings."