The North Carolina Supreme Court has upheld the state Utilities Commission in approving a 2013 rate hike by Duke Energy Carolinas, which serves the Charlotte region.
Attorney General Roy Cooper had challenged the 10.2 percent return on equity, or profit margin, the commission allowed Duke.
Cooper argued that the commission didn’t have sufficient evidence to make that decision.
Separately, the Durham advocacy group NC WARN challenged Duke’s allocation of costs, a component of rate making, on electricity demand during the single hottest hour of summer.
WARN says that method unfairly discriminates against residential customers by driving their rates disproportionately high.
The Supreme Court, in a judgment filed Wednesday, affirmed the Utilities Commission decisions on both counts.
Cooper, a likely candidate for governor in 2016, has challenged a number of utility rate hikes in recent years.
In December, the high court upheld the Utilities Commission in a 2012 Duke Energy Carolinas rate case.