First Energy Corp.’s generation subsidiaries will retire six coal-fired power plants by September 1, 2012. The reason, said spokesperson Mark Durbin, is new environmental requirements.

“By no means is it a reflection on the fine work that’s been done by our employees at those plants, but it’s related to what the financial impact will be for these new environmental rules,” he said.

Unlike previous cap and trade-type environmental requirements, new EPA regulations would affect each, individual power plant. Durbin said since the plants in question are older, it would be more expensive to bring them up to code than to simply close them.

All told, the plants in Pennsylvania, Ohio, and Maryland account for about 10 percent of the company’s total electricity generation, so the closures aren’t expected to hit consumers too hard.

“Right now there’s an excess supply of electricity. Power prices are lower as a result of that, so as far as any additional generation that would have to come on board, we don’t think that’s a consideration right now,” said Durbin.

Durbin also said more closures in Pennsylvania are unlikely.

“We are now in the process of finalizing compliance plans to make sure our existing power plants, that already have advanced environmental controls, will be outfitted and retrofitted to meet these new mercury standards by 2015,” he said.

The Pennsylvania plant being retired is the Armstrong Power Station in Washington Township, Armstrong County, near Kittanning. First Energy Corp. has 12 power plants in the state, 10 of which are either coal or natural gas.