Integrys Energy Group (NYSE: TEG) announced today that it is retiring two coal-fired power plant units totaling 112 megawatts of generating capacity.

Located in Green Bay, Wis., the units currently provide power to Integrys' Wisconsin Public Service Corp. Althouth the units have been in operation since around 1950, upgrade costs for efficiency purposes and environmental regulations are finally putting them out of action.

"[Units] Pulliam 5 & 6 served our customers well for more than 60 years," said Paul Spicer, Wisconsin Public Service vice president of energy supply, in a statement today. "In the current regional energy market, however, only the most efficient plants operate 24 hours every day as these units were designed. Converting the units or adding expensive environmental controls to keep them running just isn't in our customers' best interests."

Integrys had already been in talks with the U.S. Environmental Protection Agency to repower, refuel, or retire the two units. The utility chose the latter, and will instead focus investments on bigger coal and natural gas electricity generating facilities.

The company noted that two other Wisconsin coal-fired units may also be on the cutting board. The utility said it will announce "later this year" whether it will shutter the two units that generate 135 MW of electricity.