Solar gardens are sprouting in Minnesota.

These innovative solar power projects allow electric customers to invest in a large array off their property and own a share of the output, which gets credited to their monthly bills.

The first solar garden, a large ground-mounted system, is nearly finished in Rockford, next to the headquarters of its sponsor, the Wright Hennepin Cooperative Electric Association, which says it plans to immediately build a second one.

In Minneapolis, start-up company MN Community Solar said Thursday that it expects no shortage of investors for that city's first planned solar garden atop a business on E. Lake Street.

"The majority of residential customers and many businesses don't have a roof that works for solar energy," said the company's CEO Ken Bradley, a longtime solar energy advocate who helped push adoption of the state's new solar law, passed in May by the Minnesota Legislature. "Community solar gardens allow anyone to participate."

Dustin Denison, a company principal, said it hopes to begin construction next year on the planned 40-kilowatt solar array, which is expected to cost $180,000. It will be built atop Northern Sun Merchandising, a seller of T-shirts, buttons and other products with progressive political messages at 2916 E. Lake St.

Denison, who is also a solar installer, said MN Community Solar is looking to build even-larger solar arrays, and has begun talking to cities and businesses about potential sites. Some of those arrays could be 1-megawatt systems, or 25 times larger than the one planned on Lake Street, Denison said.

Minneapolis Mayor R.T. Rybak, a green energy supporter who came to Lake Street on Thursday for the company announcement, said the city likely has properties on which community solar projects could be built.

Meanwhile, the state's first solar garden neared completion this week in Rockford, and should be wired into the electric grid and generating power by the end of the month, said Rod Nikula, vice president of power supply for the co-op.

"We are moving ahead with the second array on the heels of the first," he said Thursday.

That array, which is about half subscribed, also will be next to the co-op headquarters. Nikula said the utility is looking for sites for more projects, including land next to substations and commercial rooftops. Wright Hennepin's arrays are the same size as the one planned on Lake Street — enough power to run about 10 homes.

Both the Minneapolis and Rockford projects are using solar panels manufactured by Bloomington-based TenKsolar, which specializes in units for flat surfaces such as rooftops.

The Rockford solar project also has a battery built by Silent Power of Baxter, Minn. It will store power generated early in the day, and release it when power demand peaks, which often happens late in the afternoon as the sun is fading.

If solar gardens gain popularity, they could help investor-owned utilities like Xcel Energy meet the recently enacted state mandate to generate 1.5 percent of their power from the sun by 2020. Utilities have a direct role in solar gardens because they must meter the electricity and credit the solar output to subscribers' bills.

"Community solar gardens can offer an opportunity for customers to participate in solar regardless of whether they own a home or are well-sited for solar panels on their property," company spokeswoman Patti Nystuen said in an e-mail.

Under the state's new solar law, Xcel must submit details to state regulators on how solar gardens will work. Nystuen said the utility will file the plan on Sept. 30. Xcel already has a popular solar garden program in its Colorado service area.

Some of the details of the Lake Street project are not firm yet, but CEO Bradley said he expects that a single unit or "leaf" — roughly the output of half of a large solar panel — will cost $950 or less. The investment includes a 25-year operating and maintenance contract that relives subscribers of any upkeep costs.

Denison said the company is working with nonprofits and other groups whose members could sign up for solar garden units. He said the financial structure also will include some outside investors who typically participate because of the tax benefits, mainly the 30 percent investment tax credit for solar. Subsidies from the utility under the new state solar law also could benefit the project.

Scott Cramer, owner of Northern Sun Merchandising, where the first Minneapolis solar garden will be built, said the technology is vastly improved from the solar panels he installed on the roof 10 years ago, which now will be taken down. "For any business owner with a flat roof, this is a good investment," Cramer said. "I can talk all day about how we are baking our planet, which we are, but … this makes business sense."

David Shaffer • 612-673-7090 Twitter: @ShafferStrib