The Potomac River Generating Station.The Potomac River Generating Station.Just a month after New York City Mayor Michael Bloomberg used it as a backdrop for his $50 million donation to the Sierra Club’s Beyond Coal campaign, officials in Alexandria, Va., announced a plan to close the GenOn coal-fired power plant:

The City of Alexandria and GenOn Energy have reached an agreement to permanently close the company’s Potomac River Generating Station, which began operating in 1949. To facilitate the retirement of the plant, the city of Alexandria will release approximately $32 million currently held in escrow, which was set aside to pay for the additional environmental controls at the station as a result of a 2008 agreement between the city and GenOn.

“Today’s announcement is a path forward for both Alexandria and the power company that works for everybody, and truly reflects the interest of both parties,” said Alexandria’s Mayor William D. Euille. “Both the Alexandria City Council and community have worked extremely hard toward this goal, and we are very proud of the final result. This news strengthens Alexandria’s future and opens the door to an enhanced quality of life for our residents.”

Under the terms of the agreement, GenOn has agreed to retire the generating station by October 1, 2012, or, if the plant is needed beyond that date for reliability purposes, as soon as it is no longer needed.

The news comes in the wake of a report that the polluting plant isn’t necessary to meet the D.C. area’s energy needs. And as David Roberts has detailed, the site on the banks of the Potomac River could be reborn as something much better than a crappy old coal plant.

I visited the site in April with the National Wildlife Federation’s Joe Mendelson, using the GenOn facility as an example of a dirty coal plant that could go unregulated in the face of a government shutdown.

Considering how long Alexandria public health and environmental advocates have been fighting to close this dirty coal-fired power plant, and in one of America’s most coal-friendly states, this is a historic victory. A long list of elected officials and conservation groups, from Rep. Jim Moran (D-Va.) to the Sierra Club, deserve credit.