The Arizona Republic

Arizona Public Service Co. and the solar industry have published conflicting studies estimating the value of rooftop solar panels, foreshadowing a debate that will determine the future of the budding solar industry in Arizona.

The APS report says that people with rooftop solar are being overpaid for the excess electricity they generate, which is directed to the power grid when they are not using it. The solar-industry report said those customers are being underpaid and that their solar panels provide value to the utility by helping APS avoid expenses like new power plants.

The two sides are making their arguments as APS prepares to ask regulators in July for a reduction in its credits. The five Arizona Corporation Commissioners will decide whether to keep or alter the payments.