COLUMBUS — State and local consumer groups have sued in the Ohio Supreme Court in hopes of preventing regulators from approving rates for FirstEnergy Corp. that the groups contend undermine what is supposed to be a competitive electricity marketplace.

The Ohio Consumers’ Counsel and the Northwest Ohio Aggregation Coalition on Tuesday appealed the Public Utility Commission of Ohio’s decision on March 31 that guaranteed profits for the utility’s coal-fired and nuclear power plants that have struggled to compete in the current market.

It has also appealed the PUCO’s subsequent decision to rehear the case, based on a revised proposal, after the Federal Energy Regulatory Commission struck down the first.

The suit contends that FirstEnergy must file a new application with the PUCO. It notes that the Supreme Court earlier this year struck down similar deals that involved Dayton Power & Light and American Electric Power.

The original deal was designed to lock in profits for FirstEnergy’s Davis-Besse nuclear plant near Oak Harbor and the coal-fired W.H. Sammis plant near Steubenville, regardless of whether consumers could find cheaper power from natural gas or other sources.

Critics contended it would cost customers of Toledo Edison and other affiliates of the Akron-based utility a total of $3.9 billion more over the eight-year life of the plan. FirstEnergy countered that its plan would keep Ohio plants in operation that might otherwise have to close and that those plants would become more competitive in the future as natural gas prices rise.

The revised proposal now being considered by the PUCO as part of the rehearing process calls for a “distribution modernization rider,” or surcharge, on customers’ power delivery bills that would allow the utility to collect $131 million annually for three years from its ratepayers.

First Published September 8, 2016, 4:00 a.m.