MINNEAPOLIS — Xcel Energy is negotiating deals for big solar projects in Minnesota.

In a regulatory filing, the Minneapolis-based power company said it is negotiating with three energy developers to build large solar projects to comply with Minnesota’s mandate that investor-owned utilities get 1.5 percent of their power from the sun by 2020.

The company said 36 energy companies proposed 111 large solar farms in response to Xcel’s request for bids. Xcel cited trade secrecy for not releasing details.

Xcel said the bid prices were “very competitive” and that 15 projects promised electricity at 8.5 cents per kilowatt hour or less. Such projects, known as “utility-scale solar,” are the most cost-effective way to get electricity from the sun, according to Xcel.

The utility also told state regulators in a recent letter that the new solar bids are “significantly less expensive” than a large solar project planned by Edina-based Geronimo Energy at locations across Xcel’s Minnesota service area. The state Public Utilities Commission in March directed Xcel to negotiate an agreement with Geronimo to build the $250 million Aurora project to serve the utility’s 1.2 million customers in the state.

Xcel now is raising the prospect that it doesn’t need both the 100-megawatt Geronimo project and 100 megawatts of newly bid utility-scale solar farms to meet its 2020 solar goals. In a revision of its projections, Xcel said it needs 100 megawatts of utility-scale solar to comply with the mandate set by the 2013 state solar law. A megawatt is 1 million watts, enough to supply about 200 homes.

Besides building the big solar farms, Xcel also expects that consumer-developed solar projects, including rooftop systems and shared arrays known as community solar gardens, will add another 100 megawatts of sun-generated power to its Minnesota system by 2020, Jim Alders, Xcel’s strategy consultant on regulatory affairs, said in an interview.

Betsy Engelking, a vice president for Geronimo, also said it’s unfair to compare the projected cost of the newly bid solar farms with the Geronimo project, whose other special features include a financial assurance to Xcel about delivering electricity when customer demand spikes.