In the Mid-Atlantic region, the decline in natural gas prices led to an increase in the use of natural gas for power generation, but the region remains mostly fueled by coal and nuclear sources of electricity.
The Mid-Atlantic electric region in this analysis is represented by the PJM Interconnection's electric system, the largest single electric system in the nation in terms of customers served. The fuel mix in this region has remained fairly consistent, compared to the larger shifts seen in other regions.
Natural gas power generation increased because of low natural gas prices in 2012 and 2013 (especially in states such as Ohio and Pennsylvania), but the availability of cheap coal from the Illinois Basin has kept coal-fired units producing nearly half of the output in PJM's system, especially in the western portion (Indiana and Illinois).
Although natural gas-fired units do not make up a majority of the generation units in this region, these units often set the wholesale electricity price. This is because in the PJM market, the electricity price is determined by the last unit selected (the marginal unit) to run at a given time, based on fuel and other operating costs. Because natural gas often fuels the last unit selected, the wholesale power price in the PJM system generally moves with the natural gas price on any given day (see graph below).
Principal contributor: M. Tyson Brown