NCUC has ruled that Duke Energy could not recover its full costs under the state renewable-energy standard. The standard requires that solar power produce a small percentage of Duke Energy’s overall output beginning in 2010.

Duke Energy had already cut in half its original $100 million, 16 MW solar rooftop plan after objections from NCUC’s public staff.

The first proposal, coupled with Duke Energy’s plan to also buy the 16 MW output of a solar farm to be built in Davidson county, meant the company would produce much more solar power than the state requires, NCUC public staff said.