Xcel Energy and two solar industry groups have made a joint interim proposal to Colorado utility regulators on incentives that encourage customers to put panels on their roofs, they said Tuesday.

In announcing their agreement a day before the Colorado Public Utilities Commission opens hearing on Xcel's renewable-energy policy plan, they made clear the contentious issue of net metering remains unresolved.

Xcel, the Solar Industries Association and the Colorado Solar Energy Industries Association called in their agreement for the commission to approve 3 cents per kilowatt hour of Solar Rewards for customer-owned installations of up to 25 kilowatts and 1 cent per kilowatt hour for small installations owned by parties other than the homeowner, keeping the program active pending approval of the overall renewable energy plan.

They also proposed restarting a medium program for solar arrays of between 25 and 500 kilowatts that had been closed since October 2013, when that program's capacity was reached. For the medium program, incentives were proposed of 6 cents per kilowatt hour for the first six megawatts and 5 cents for the final megawatt.

"It does show that there are issues that we can agree on," Xcel spokesman Mark Stutz told The Associated Press after the agreement was announced. "Certainly both Xcel Energy and those in the solar industry agree that rooftop solar energy is important to Colorado."

But Stutz said Xcel still had concerns about net metering, which allows homeowners with rooftop solar arrays to, in addition to Solar Rewards, get credit for the energy they put back into the grid to be sold on to others. The commission earlier this year separated a discussion of net metering from the overall review after Xcel proposed taking steps to inform consumers what part of the net-metering credit reflects the value of the energy produced and what part should be seen as a subsidy. Solar proponents have objected, saying they believe Xcel is laying a foundation for changes to net metering that could hurt the industry.

Utility companies have been challenging net metering around the country.