PJM Interconnection’s electric system, the largest in the nation in terms of customers served, is mostly powered by coal and nuclear energy sources, though the use of natural gas has increased since 2012, according to the U.S. Energy Information Administration (EIA).
The report refers to PJM’s service area as the Mid-Atlantic region. The region has seen a decrease in natural gas prices, which led to an increase in the use of natural gas for power generation, the report says. However, the availability of inexpensive coal from the Illinois Basin has kept coal-fired units producing nearly half of the output in PJM’s system.
Natural gas-fired units do not make up a majority of the generating units in the region, but they often set the wholesale electricity price, since the electricity price is determined by the last unit selected to run at a given time in the PJM market. Since natural gas units are often the fuels last selected, the wholesale power price generally goes with the natural gas price on any given day.