A new report for Rice Creek Commons, the former Army ammunitions site in Arden Hills, says a new solar farm — as well as using groundwater now being treated by the Army for heating and cooling — could satisfy all the 427-acre development's energy needs.

The report, called the Energy Integration Resiliency Framework for Rice Creek Commons, outlines a vision to make the development the largest in the state to be energy self-sufficient.

At the heart of the proposal are plans to install an on-site 40-acre solar array and use water the Army is now treating to heat and cool homes and businesses.

"We have an opportunity to use today's technology to build a sustainable energy future," said Ramsey County Commissioner Blake Huffman, who represents the area.

But the county must move quickly, Huffman said, to obtain a 60-acre site just north of the development to use for the solar array. The solar project must be in place by the end of 2016 to utilize federal tax credits to offset the cost. Ramsey County officials plan to ask the federal General Services Administration to give it the site for free.

In exchange, the county would clean up the site to meet industrial standards, which county officials said would cost about $1.25 million.

When complete, the solar installation would use 40 acres and generate 8 megawatts of electricity. That is enough power to meet the needs of the entire Rice Creek Commons development. Officials say that's also enough power to reduce greenhouse gas emissions each year by the equivalent of removing 1,432 cars from the roads.

The second piece of the energy plan would use groundwater to heat and cool homes and businesses. The Army currently is pumping 2 million gallons of contaminated groundwater each day, treating it and dumping it into Marsden Lake. Heat from that 52-degree water could be captured and used to heat and cool all or parts of the development, said Greg Mack, project manager for the county.

"It would be just taking advantage of resources that are there," Mack said.

Ramsey County is seeking to partner with the Minnesota Army National Guard, which owns and operates the Arden Hills Army Training Site next to Rice Creek Commons. The Guard's master plan for its training site is to "take it off the grid" for energy, water and waste, Huffman said.

The county is contacting third parties interested in public-private partnerships to develop the solar field. Future developers would become part of the discussions for the geothermal piece. Altogether, Huffman said, the prospects for using technology to decrease the site's carbon footprint are exciting.

"There are just a lot of wins out there. But, of course it's complicated," Huffman said.

James Walsh • 612-673-7428