New Threat to the Grid

The Wall Street Journal reports A New Threat to Power Grids: Data Centers Unplugging at Once

Early last year, a cluster of data centers in Virginia suddenly dropped off the power grid, threatening the stability of the already vulnerable system.

The roughly 40 data centers, which had been using enough electricity to supply more than one million homes, simultaneously switched to backup power sources in February 2025, when a high-voltage power line malfunctioned. The sudden plunge in electricity demand forced the grid operator to take quick action to avoid potentially serious damage.

The incident, details of which haven't been reported, was the second such problem in Virginia within a span of months. In July 2024, about 70 data centers withdrew from the grid when another high-voltage line failed, requiring a similar scramble to keep power supply and demand in line.

Balancing the two is critical in maintaining the health of the grid: Both undersupply and oversupply of electricity demand can cause power plants to fail, resulting in blackouts and repair challenges. The issue is especially pressing in Virginia, where data centers are projected to use as much as 57% of the state's electricity by 2030.

In both instances, the loss in data-center demand totaled less than 2,000 megawatts—a substantial amount of power, but not enough to create a crisis for the grid operator, known as PJM Interconnection. PJM had operations in place to quickly reduce the amount of supply on the grid in response to the demand loss.

"It didn't cause an emergency, but I would say it caused concern," said Mike Bryson, PJM's senior vice president of operations. "What we're worried about is, what if that happens for 3,000 megawatts or 5,000 megawatts?"

Concerns about the rapid build-out of data centers often center on the risk that adding too many in a given region could strain electricity supplies, particularly on hot or cold days when demand is high. If demand threatens to exceed supply, grid operators call on power plants to ramp up production and, as a last resort, order utilities to cut power to customers to maintain balance.

Now, the opposite risk is emerging. Data centers are equipped with technologies that monitor for disturbances on the grid that could cause a power outage and affect operations. When disturbances occur, many data centers automatically shift to backup supplies, severing their grid connections until power quality stabilizes.

Both risks have been most acute within PJM, which operates a power market spanning 13 states from New Jersey to Kentucky. Home to the largest concentration of data centers in the world, PJM has for years been grappling with the prospect of electricity supply shortages as the enormous facilities use more and more power. The prospect of them disappearing unexpectedly causes more headaches for the grid operator.