UPDATE 2-FirstEnergy to retire 6 power plants, incur charges

* Says closure to affect 529 employees

* Says to take $244 mln charge in Q4

* Sees closure reducing 2011 earnings by $0.38/shr

Jan 26 (Reuters) - FirstEnergy will retire six coal-fired power plants by September as the U.S. environmental regulator tightens regulations, and the diversified energy company said it will take a related charge.

The company expects to incur charges of $244 million related to the closure in the fourth quarter, and sees 2011 earnings reduced by 38 cents a share.

Analysts on average are expecting the company to report full-year earnings of $3.38, according to Thomson Reuters I/B/E/S.

FirstEnergy also said it expects to incur costs of about $6 million in 2012 to prepare the plants for closing.

The closing of plants in Ohio, Pennsylvania and Maryland will cut production by about 10 percent and affect 529 employees.

The recently finalized U.S. Environmental Protection Agency's Mercury and Air Toxics Standards (MATS) formulate stringent standards for power plants' emission of mercury and other toxic air pollutants.

"Additional investments to implement MATS and other environmental rules would make these older plants even less likely to be dispatched under market rules... it was necessary to retire the plants rather than continue operations," President James Lash said in a statement.

Akron, Ohio-based FirstEnergy, which has six million customers, runs about 64 percent of its plants on coal.

The company said it is finalising MATS compliance plans for its remaining coal-fired units. (Reporting by Vaishnavi Bala in Bangalore; Editing by Sriraj Kalluvila)((vaishnavi.bala@thomsonreuters.com within U.S. +1 646 223 8780 outside U.S. +91 80 4135 5800 Reuters Messaging:vaishnavi.bala.reuters.com@reuters.net)