PJM coordinates the movement of electricity across 56,070 miles of transmission lines through 13 states and Washington, D.C.

Utilities buy our power through the PJM Interconnection energy market, and deliver the electricity to millions of consumers and businesses in a multi-state area that includes our nation’s capital. We sell into a competitive wholesale market — which means our prices are dictated by market forces and are not regulated rates.

PJM, which stands for Pennsylvania-New Jersey-Maryland, is a regional transmission organization (RTO) that coordinates the movement of electricity across 56,070 miles of transmission lines, through 13 states, including Virginia, and Washington, D.C. Because electricity can’t be stored for future use, PJM orders power generation based on forecasted demand. As an example, the Potomac River Generating Station would typically be asked a day ahead to produce a certain number of megawatts for a certain number of hours over a specified timeframe.

It is PJM, not Mirant, that decides when and how much our plant generates.

Reliability is key

The District of Columbia Public Service Commission (DCPSC) counts on the nearby Potomac River Generating Station to ensure reliable power for much of Washington, D.C.’s central business district, including many federal institutions.

At present, electricity can be provided to D.C. by only three means: from the Potomac River Generating Station, or over two high-voltage (230 kV) transmission lines that deliver electricity from other generating sources in the regional electric grid operated by PJM. Should these high-voltage transmission lines suffer an overload condition during peak usage periods, only the Potomac River plant could satisfy the immediate needs of the District. In addition, Potomac River Generating Station has the ability to respond to the changing demand for electricity, quickly raising or lowering its load as needed. Not all generating stations have this capability.