The rapid development of shale gas resources in Pennsylvania, Ohio, and West Virginia has contributed to sustained low natural gas prices and encouraged the construction of natural gas-fired power plants. About one-third of the new natural gas-fired generating capacity built in the United States since 2010 is located in PJM Interconnection (PJM), the grid operator for all or parts of 13 states in the mid-Atlantic region, including Pennsylvania, Ohio, and West Virginia. In 2020, the utilization rate, called capacity factor, of natural gas-fired combined-cycle (NGCC) units built from 2010 to 2020 in PJM was 71%, which was higher than that of older units in the region.