PJM Asks Big Power Users to Cut Demand as Heat Strains Grid

PJM Interconnection, which operates the largest regional electric grid in the United States, asked large energy consumers across 13 states to reduce their consumption on Thursday as high temperatures pushed up power demand and raised the risk of blackouts.

The grid covers the Mid-Atlantic and Midwest and supplies electricity to roughly one in five Americans. PJM said about 36,000 megawatts of generation were offline on its system, reducing the power available to meet demand.

The operator activated its "demand response" programme, which pays participating customers to temporarily cut or reduce their electricity use when called upon. Such measures are intended to help avoid rolling blackouts.

Above-average temperatures increase consumption as homes and businesses run cooling systems, straining supplies at a time when transmission and power plant operators are beginning maintenance work.

Demand in PJM's territory has grown faster than new electricity supplies in recent years, tightening the margin between available power and peak consumption. The region includes the world's largest data centre hub in northern Virginia, known as "Data Center Alley", along with expanding clusters in states such as Pennsylvania and Ohio.

The US Department of Energy granted PJM's request to temporarily waive environmental permit restrictions for certain power plants and to allow energy-intensive data centres to switch to backup generators, which can be more polluting than other sources of electricity.

PJM said it may also curtail power exports as part of its emergency measures, noting that weather has been increasingly hot for neighbouring systems to the south and west.