This is a Sierra Club event. From the Sierra Club outings website:
"Learn about the transition from dirty to clean energy in the nation's capital. Meet at the Capitol South Metro station. We will walk to the Capitol Power Plant, which is the last coal-burning power station in the city. We will walk north, past many federal buildings with large rooftop solar arrays, through Catholic University, with its many solar projects, and finish at Fort Totten. Total distance is about 7 miles, the majority on the Metropolitan Branch Trail. This is a one-way hike that begins and ends at two separate Metro stations miles apart from one another.
Bring snack, water and money to buy lunch at Union Station"