American Electric Power (AEP -1.04%) announced today that it is adding another coal-fired power plant to its growing list of soon-to-be-retired facilities.

This latest addition, a 585 MW Ohio facility, brings the utility's grand total to 3,123 MW of coal-fueled generation retired by 2016 for its Ohio subsidiary.

In its press release, AEP noted that both environmental regulation costs and "current market conditions" have made it very unlikely that the utility will continue to use this unit in the coming years, although there is a possibility of a potential natural gas refuel.

This latest decision won't affect AEP's 2013 operating earnings, but the company will take a $150 million to $170 million non-operating pre-tax hit in Q2. AEP also noted that it will continue to stick with its previous earnings growth rate guidance of 4% to 6%. 

Accounting for this latest retirement plan, AEP Ohio's total generation capacity will clock in at 10,725 MW, which will be "mostly" comprised of "clean coal" and natural gas plants, as well as a small hydro unit.