American Electric Power awaits a district court decision that could affect three of its Ohio plants and add fines to a $4 billion renovation project — the costs of which are being passed along to consumers.

AEP recently completed renovations to bring its 25 coal-fired plants up to Clean Air Act standards by reducing the emissions of mercury, nitrous oxide and sulfur dioxide, major contributors to acid rain, said AEP spokeswoman Melissa McHenry.

The costs of the renovations are being passed on to more than 5 million AEP customers in 11 states, but Ohio customers will pay a higher proportion of the costs for renovations to Ohio power plants, McHenry said. AEP is one of the largest electricity suppliers to Athens County.

AEP also could face fines if it loses a lawsuit filed by the Environmental Protection Agency, which alleges that AEP previously had modified nine of its plants, including three in central and southern Ohio, without obtaining permits, she said.

It is impossible to estimate fines in any EPA case because each case is assessed independently based on the number, duration and severity of violations, as well as the effect on the environment, said Bruce Weinberg of the Ohio EPA.

Many energy companies have been hesitant to file for permits when modifying older plants because it would force the plants to meet newer, more stringent Clean Air Act standards, Weinberg said.

“The EPA has taken a lot of action in trying to get these plants to come up to standards with today’s regulations,” he said, adding that filing against companies that have made modifications to their plants is one way to force them to meet current clean air regulations.

Weinberg said the Clean Air Act is not applicable to older, unmodified plants, because it was originally believed that those plants would be shut down before they could adversely affect the environment.

A district court judge delayed the decision in the AEP case to await the April 2 ruling in a similar U.S. Supreme Court case,

McHenry said, though no date has been set for the AEP decision.

In a similar case, the U.S. Supreme Court set aside lower court rulings that favored Duke Energy Corporation. The ruling indicated that annual rather than hourly emission standards need to be considered in determining whether Duke should have obtained permits for modifications to its eight coal-fired plants in North Carolina and South Carolina. As a result, the Duke case will be continued in lower courts.

AEP’s McHenry said that decision might not influence her company’s district court case, because the Duke case failed to specifically define what qualifies as a major modification requiring a permit.

“The Supreme Court decision was one very small case,” McHenry said. “How that translates to AEP, it’s really too soon to say.”

Ohio EPA’s Weinberg, however, thinks the U.S. Supreme Court ruling could set a precedent.

“This is a decision that will certainly impact hundreds of these older plants,” Weinberg said. “If that decision is going to be used by the courts here (in AEP case), you can clearly see the direction they will be going.”