Rochester, Minnesota (source: Tony Asleson / flickr, Creative Commons)“After it’s completed and the project’s done, we’ll have the second city hall in Minnesota that is electrically heated and cooled with geothermal, which is pretty exciting,” said Kevin Bright, former director of housing and sustainability and one of the people who helped launch the geothermal project.
The development of geothermal is part of the city’s strategy to reduce greenhouse gases by 100% over the next three decades. The long-term plan would be to create an underground network of pipes that will efficiently supply heating and cooling to the new residential and commercial buildings downtown.
The initial phases of this project is expected to be completed by 2025, officials say.
Joe Dammel, Managing Director of the advocacy group Fresh Energy, described how such a system becomes more efficient when more buildings are linked together. “You use the heat that’s stored there as a way to heat a building so you’re pulling heat from the ground and putting it into buildings. In cooling mode, you’re pulling heat from buildings and putting it back to the ground for storage.”
Federal financing paved the way for geothermal
The geothermal project in Rochester has become financially feasible because of new federal financing options incentivizing project that result in large-scale carbon emissions. As Dammel said, the Inflation Reduction Act that Congress passed about a year ago has removed the usual cost barriers of geothermal.
The projected cost of Rochester’s geothermal system is about USD 34 million. About half of that cost will be covered by incentives under the Inflation Reduction Act, as well as smaller public funding sources.
“The state and federal policy is really shifting towards a different way of heating. And we think in Minnesota that network geothermal is a really promising technology to accomplish that,” Dammel further commented.
The benefit of homegrown technology
Technology has also been one of the key drivers for the realization of this project. The system only requires the drilling of two wells thanks to the design innovations developed in the University of Minnesota and commercialized by Darcy Solutions.
“What we do is instead of exchanging energy with just the ground and soil and rock, we exchange energy with groundwater in the aquifers below us,” said Andrew Steiner, chief operating officer for Darcy Solutions.
By tapping into naturally occurring aquifers, the geothermal heat pumps do not need to do a lot of work for heating and cooling. This means that geothermal systems can have smaller footprints and require the drilling of fewer wells, thus also reducing capital and operating costs.
