Solar panels on the fire hall rooftop, Aug. 2, 2013 in Red Wing. Jennifer Simonson / MPR News 2013

The new community solar program Xcel Energy will launch on Friday could mean a big boost in solar electricity for the utility.

Xcel has about 14 megawatts in its system right now. The Solar Rewards Community could add 100 megawatts in 2015, or about enough to serve 25,000 homes, said Xcel Senior Vice President Laura McCarten.

"This really all depends on the interest of consumers who want to participate in this type of program, what developers put together and offer to consumers and how that market develops," she said. "It's something that none of us really know for sure but we will find out as we go forward. We do expect a high level of interest and activity."

Here's how it works: Rather than installing solar panels on their rooftops, utility customers — and even apartment dwellers — can subscribe to a community solar garden. The customer chooses how much solar power to buy or lease, and whatever the panel produces will be credited on the customer's Xcel electricity bill.

It's not clear yet how much it will cost the average utility customer to participate in the community solar gardens.

McCarten says developers' offers to consumers could vary. The first installations are expected to be up and running by mid-2015.

While Xcel predicts developers will offer up to 100 megawatts in the program next year, McCarten said there is no cap if interest is higher. That contrasts with Xcel's program in Colorado, where there is a cap.

Meanwhile, Xcel is pursuing larger, utility-scale solar installations that will also boost the company's renewable energy portfolio.

Both efforts will help Xcel meet a state requirement to produce 1.5 percent of its power from solar by 2020.