Seven years after the Texas Legislature passed a bill calling for the state to add 500 megawatts of non-wind renewable power to its energy mix by 2015, the Public Utility Commission has yet to enforce the law. Solar power advocates are urging the commission to enact rules that would implement the change and add another 2,500 megawatts to the target by 2025.

The Renewable Portfolio Standard passed in 1999 under Gov. George Bush was largely responsible for kick-starting wind energy in Texas and making the state the national leader in wind capacity. Advocates say the 500 MW non-wind provision could do the same for solar energy.

But the commission has declined to adopt the rule. PUC chair Donna Nelson has said the target set by the Legislature is not a mandate, and that the commission doesn’t have the authority to enforce the rule. The Sierra Club and a dozen other groups filed a petition with the commission in September requesting they open a rulemaking process to claim that authority, but the commission has until November to decide whether it wants to do that or not.