PJM Electric Grid Withstands High Winter Storm Demand

The Mid-Atlantic power grid operated by PJM Interconnection withstood the recent winter storm that brought heavy snow and arctic temperatures to the area, but not without concerns and precautionary measures.

Winter Storm Fern hit much of the East with a prolonged period of extremely cold temperatures, raising concerns about whether the PJM grid that serves 13 Mid-Atlantic states, including Pennsylvania, would exceed its all-time winter peak hourly demand of 143,700 megawatts (MW), which was set last January.

While electricity demand was at high levels for over a week, with peak demand on Jan. 27 and 28 reaching about 137,000 MW, a new record was not set. PJM attributed this to school and government closings due to the snow and extreme cold, keeping electric use down slightly.

PJM’s grid was already under stress before the storm due to rapidly increasing electric demand, much of it from data centers, while new generation sources are not coming online fast enough and older fossil fuel powered plants are retiring. This has created a supply-demand imbalance and pushed electric prices up.

In anticipation of the polar vortex, PJM and the U.S. Department of Energy took several steps to ensure that adequate generation was available to avoid blackouts. PJM directed data center operators and other large load customers to be prepared to use backup generation sources if needed to prevent strain on the grid. DOE estimates that more than 35 GW of unused backup generation is available nationwide. DOE also directed power plants to operate at maximum generating capacity regardless of air pollution or other permit limits.

The U.S. Energy Information Administration noted that during the week of the winter storm, natural gas generation across the country increased 14% from the previous week. Coal accounted for 21% of all electricity generation over the same period, up from 17% the previous week. Coal was the second-largest source of energy used for electricity, following natural gas. Coal generation can be ramped up during extreme weather events to meet demand surges and make up for outages from other energy sources.

PJM made changes after Winter Storm Elliott in 2023, when a bomb cyclone caused a drastic drop in temperatures and caused a significant amount of generation infrastructure to freeze up, knocking it offline. Some 70 percent of the outages, totaling 32,473 megawatts (MW) of lost power, were from generation failures at natural gas-fired plants. Natural gas is the most commonly used fuel among PJM power generators, making up about 40% of the fuel mix.

A review led to changes in reliability standards for natural gas power plant operators and the grid itself to ensure that power generation would not be knocked offline during future storms.