Large-scale solar power projects could be coming to the edges of three Minnesota cities.

Xcel Energy Inc. said Friday that it has signed deals with three energy developers to construct up to three giant fields of solar panels near North Branch, Marshall and Tracy by late 2016 to comply with a new state renewable energy mandate.

Xcel, the largest power company in the state with 1.2 million electric customers, said in a filing with state regulators that it wants to go ahead with at least two of the projects, a 62-megawatt system near Marshall proposed by NextEra Energy Resources, based in Juno Beach, Fla., and a 25-megawatt array near Tracy planned by Juwi Solar, based in Boulder, Colo.

The largest of the proposed projects is a 100-megawatt solar generator near North Branch that would be built by Community Energy Resources, based in Radnor, Pa. But Xcel said that project may be unnecessary, if utility regulators give final approval to a planned, 100-megawatt solar project from Edina-based Geronimo Energy that would also serve Xcel customers.

With the three new projects, Xcel would get the equivalent of a modest-sized traditional generating station. Xcel wouldn’t own the solar farms, but would purchase all the energy, which will be equivalent to the amount used by 41,000 homes, Xcel said.

Xcel did not disclose the price of the solar power under the 25-year purchase agreements, declaring those details trade secrets. Dave Sparby, CEO of Xcel’s Minnesota regional operation, said the prices resulting from competitive bids “will provide substantial benefit to our customers” and avoid 7 million tons of carbon dioxide emissions annually.

“As such, these resources continue the significant progress we’ve made during the last decade in cost-effectively improving our environmental performance,” Sparby said in a statement.

Under a 2013 state law, investor-owned utilities like Xcel are required to get 1.5 percent of their electricity from the sun by 2020. That mandate is on top of the state’s existing renewable-energy requirements that are a factor in Xcel’s industry-leading investments in wind power.

Both the North Branch and Tracy solar projects plan to use solar panels that move on an axis, tracking the angle of the sun as it moves across the sky, according to a 457-page Xcel regulatory filing late Friday. Tracking systems allow solar arrays to collect more energy, especially late in the day in the summer when power demand often spikes.

The Minnesota Public Utilities Commission, which must approve all of the power-purchase deals, has already given preliminary approval to Geronimo Energy’s planned Aurora Solar project, to be built at up to 20 locations across Minnesota. That project was a winner in an earlier competitive process against three, natural gas-based generating proposals, including one that Xcel wants to build at its Black Dog generation plant in Burnsville.

But Xcel recently asked the commission to consider whether the latest solar proposals are a better deal than the Aurora project. Geronimo has objected to Xcel’s effort to reopen the issue.