Power plant outages surge in Eastern US amid restricted gas supplies, frigid weather

Power plant outages surged along the eastern United States on Sunday (26 January) as constricted natural gas supplies and frigid temperatures cut the electricity output of the region's generation fleet.

The PJM Interconnection, the largest US regional grid that serves 67 million people in the East and Mid-Atlantic, reported nearly 21 gigawatts of generation outages, with most of that capacity being forced offline. Those outages represented about 16% of PJM's Sunday afternoon demand of 127.4 GW.

On Sunday afternoon, PJM issued a pre-emergency order mandating that some customers in its curtailment program curb their electricity use. Customers in the program get paid to curb their electricity during critical periods.

PJM's order sought to ease an upswing in demand in PJM's territory while asking some generator operators to preserve their run time for colder weather and higher electricity demand later in the week.

Without native supplies of natural gas, the Eastern seaboard relies on a pipeline network that is historically constricted during extended bouts of frigid weather, said Pieter Mul, a grid expert and associate partner at PA Consulting's energy and utilities practice.

Domestic demand of natural gas, net of exports, is estimated at 146.7 Bcf/d, down 3.6 Bcf/d compared to Saturday and ranks at No. 10 all-time.

"From a natural gas production and price perspective, the current US winter storm so far is less severe than prior storms such as Uri and Elliott of 2021, 2022, but the risk isn't over, with sustained cold lingering behind the storm," said Matthew Palmer, the head of Americas Gas Research at S&P Global Energy.

PJM's outages are higher than the grid planned, Mul said, adding that there is less flexibility in the PJM system than a few years ago because of power plant retirements and a surge in demand from data centres.

PJM's territory also is hurt by bottlenecks in its transmission system of high-voltage power lines, hindering the transfer from west to east. For example, cheap power in Illinois on Sunday - sometimes dipping into negative prices because of abundant wind energy - could not be moved to help out other sections of PJM.

As snow and sleet hit the major cities of Boston, New York, Philadelphia and Washington, DC, the power grid also lost access to solar power in the afternoon from an increase in cloud cover.

Meanwhile, power prices in PJM and the electric grids for New York and New England surged between $400 and $700 per MWh on Sunday afternoon, grid operators reported. The increases reflected demand that continues to top grid operator forecasts.

ISO New England, which serves a six-state region that includes Boston and Hartford, reported about 20.2 gigawatts of demand at 1:45 p.m. EDT, or greater than a projected peak load of 19.5 GW expected later in the day.

With constricted natural gas access, nearly 40% of the New England grid's output came from oil-fired power plants. Natural gas, usually the grid's main source of fuel, accounted for just 30% of the grid's fuel source for power plants.

But as Mul noted, New England's supply of diesel fuel oil can be depleted and not easily resupplied during hazardous winter conditions. ISO New England's surplus capacity dropped to about 1.1 GW, down from earlier estimates of several gigawatts.

Earlier on Sunday, ISO New England issued an "abnormal conditions" alert asking power plant operators not to schedule any maintenance or anything else that would affect the grid's reliability.

Outside of Washington D.C., real-time wholesale electricity prices topped $1,800 per MWh early Sunday in Dominion Energy's Virginia territory, up from $200 per MWh on Saturday morning. Virginia houses the biggest cluster of data centres in the world, which are used to power things like artificial intelligence and have been responsible for rising power demand and prices in swaths of the country.

The demand spike began late Saturday night, according to data from PJM as Winter Storm Fern swept across parts of the country.

PJM predicts an all-time winter demand record on Tuesday, partly due to data center electricity needs. Dominion has said extended frigid temperatures this week, along with heavy snow, have the potential to be one of the largest winter events to affect the utility's operations.

PJM predicts demand at 147.2 gigawatts, which would beat the current record winter electricity demand of 143.7 GW set in January 2025.

Spot wholesale electricity prices across the US have been elevated throughout the weekend as regional grids strain to meet surging demand. When demand is higher than the forecasts, utilities can be forced to pay elevated spot prices for electricity to meet the demands of their residential and business customers.

Regional grids feed their power into the local distribution lines that bring electricity to homes and businesses. Those local power lines are showing disruptions, with nearly 1 million customers without power on Sunday, according to PowerOutage.us, with more than 300,000 in Tennessee and more than 100,000 each in Mississippi, Texas and Louisiana. Other states affected included Kentucky, Georgia, Virginia and Alabama.

The Electric Reliability Council of Texas (ERCOT), the state's main grid operator, forecast peak demand of 85.1 GW for Monday morning, compared to seasonal capacity of nearly 100 GW. Day-ahead market prices indicate the price of electricity per MWh could top $1,000 on Monday morning, according to ERCOT data.