NRG Energy Inc. said Friday that it notified the region's grid operator of plans to retire all coal-fired generation units at two of its Maryland power plants, facilities that are the subject of a water-pollution suit by state regulators.
NRG filed deactivation notices that would allow it to shut down the Washington-area units in May 2017, a decision hailed by environmental activists. The company blamed the impact of cheap natural gas, which has made coal a less competitive source of fuel for electricity, and the need to put in more emissions-reducing equipment if Maryland moves forward with tougher coal-plant rules under discussion.
"It simply wouldn't be economic, given market conditions and the pressure that is on coal plants right now," said David Gaier, a spokesman for NRG's east region. "We'll obviously continue to evaluate our options."
The deactivation notices can be rescinded if company executives change their minds, Gaier said.
The five units, all about 50 years old, are located at the Chalk Point plant in Prince George's County and the Dickerson plant in Montgomery County. They can produce about 1,200 megawatts of electricity combined.
The plants would continue to operate with a dozen oil- and gas-fired units.
The Sierra Club said in a statement Friday that the number of Maryland plants fired by coal would drop to five if the units are shut down, a move it said would "protect public health and continue Maryland's transition from dirty, outdated coal toward more clean energy."
A federal suit filed by the Maryland Department of the Environment in June alleged that problems with the two plants' wastewater treatment systems caused the facilities to discharge more nitrogen than permitted into the Patuxent and Potomac rivers since 2010. Nitrogen pollution can set off a chain reaction that leads to water "dead zones."
NRG is in settlement talks in that case with state regulators and environment groups that intervened.