The White House, the Capitol, and other government buildings were plunged into darkness on Tuesday due to scattered power outages in the D.C. area.
SMECO said the outages were widespread throughout the area.
The outage is believed to have been caused by an explosion at a Maryland power plant, a Homeland Security spokesperson told the Associated Press.
Pepco said on Twitter that the outage was due to a "dip in voltage in the Washington D.C. area."
They said it was caused by an issue with a "transmission line" in Maryland.
"There was never a loss of permanent electric supply but dip in voltage caused equipment at some facilities to transfer to backup systems," it said.