An intense heatwave sweeping across the eastern United States has pushed the country’s largest electricity grid to the brink, prompting emergency measures to reduce power consumption and prevent widespread outages. PJM Interconnection, the regional transmission organization that supplies electricity to nearly 67 million people across 13 states and the District of Columbia, has issued an emergency alert as soaring temperatures, equipment outages and transmission constraints place unprecedented pressure on the power system.
The grid operator said electricity demand has surged sharply as millions of households and businesses rely heavily on air conditioning to cope with the extreme weather. At the same time, several power generation units have been unavailable because of outages, while overloaded transmission lines have limited the movement of electricity across the network. The combination of these factors has significantly reduced the grid’s operating flexibility and increased the risk of supply shortages.
To stabilize the system, PJM activated emergency demand-response programmes that require participating industrial facilities and large commercial consumers to temporarily reduce electricity consumption during peak demand hours. Residential consumers enrolled in such programmes have also been asked to lower their electricity usage to ease pressure on the grid. These measures are designed to avoid more severe actions such as controlled power cuts or rolling blackouts.
The emergency follows a federal order issued by the US Department of Energy, which granted PJM additional authority to maintain reliable electricity supplies during the ongoing heatwave. The order allows the grid operator to take extraordinary steps, including maximizing available electricity generation and implementing emergency demand management strategies whenever necessary to protect grid stability.
Electricity demand in the PJM service area has climbed close to historic levels, approaching records that have remained unbeaten for nearly two decades. The surge in consumption has also triggered a dramatic spike in wholesale electricity prices, with rates rising from normal levels of around $40 per megawatt-hour to more than $2,500 during periods of peak demand in some regions. The increase reflects the need to dispatch expensive backup generating stations and manage congestion across key transmission corridors.
Grid operators have indicated that demand remains especially high in regions with rapidly expanding data centres, particularly parts of the Mid-Atlantic, where electricity consumption has increased substantially in recent years. Combined with extreme weather conditions, this growth has added further stress to the power infrastructure. Authorities continue to monitor the situation closely as temperatures remain well above seasonal averages heading into the Independence Day weekend.
Although PJM has managed to maintain uninterrupted electricity supplies so far, officials warned that continued conservation efforts will be essential if the heatwave persists. Consumers have been encouraged to reduce unnecessary electricity use, delay operating energy-intensive appliances until off-peak hours and set air conditioners at higher temperatures wherever possible. Such voluntary conservation, officials said, can play a crucial role in easing demand and maintaining the reliability of the power grid during periods of exceptional stress.
