The Twin Cities Army Ammunition Plant site is nearly cleaned up and officials are eyeing their next ambitious step — a solar energy project to power the site's future homes and businesses.
Ramsey County, which owns the sprawling 427-acre site, wants to build a 40-acre array of solar panels to produce eight megawatts of electricity — enough, they say, to meet the needs of a development that would house 4,000 people and employ about the same.
Officials also hope to tap into the site's history by using the Army's water treatment plant to heat and cool homes.
"It is kind of a transformative moment," Heather Worthington, the county's deputy manager, said of the ex-Superfund site, which sat polluted and abandoned for decades. "It will be pretty amazing. You're taking something that's a negative and really making it a positive."
The solar moment, at least, remains months, if not years, away. The county will need to find a contractor to set up the solar array, Worthington said. If that happens before the end of next year, the contractor would be able to reap the 30 percent federal tax credit on the purchase of solar systems.
Ramsey County will put out a request for contractor proposals by the end of the summer.
• December 2014: Bullets to boulevards: Ex-Twin Cities ammo plant ready to develop
Innovation and falling solar panel prices make this kind of net-zero energy projects possible, said Michael Noble, executive director of Fresh Energy, which advocates for renewable energy projects in Minnesota.
"Things that were unimaginable five years ago are technically possible now," he said. "A community that is producing as much energy as it consumes is now possible and doable and is on the drawing boards in the Twin Cities."
Xcel Energy is interested in the project, known as Rice Creek Commons, said Laura McCarten, a regional vice president with the company.
"We certainly see the energy business as changing," she said. "We think that the Rice Creek Commons development provides a great opportunity for us to partner with the county, the city to test some of these things and see how they work going forward. It's a very exciting opportunity."
Ramsey County officials say the Arden Hills site would be the largest development to aim for such a high level of energy efficiency in the state. But others may follow.
The idea of a self-sustaining development is being floated by St. Paul as city leaders weigh plans for the old Ford Plant site next to the Mississippi River.
Extreme energy efficiency makes more economic sense now, especially on large projects, said John Breitinger, a development adviser with the real estate firm Cushman & Wakefield/NorthMarq.
It's also something consumers and builders will want, he added. "I think you'll see this on every project of this scale."