The operator of the largest electricity grid in the United States has ordered emergency electricity reductions as a prolonged heatwave pushed power demand close to record levels.
PJM Interconnection issued an emergency demand response order on Friday, requiring customers enrolled in electricity reduction programmes to temporarily cut their power use. The measure was introduced to maintain enough electricity reserves and prevent possible blackouts during the evening peak in demand.
The order applies to industrial facilities and residential customers who receive payments for reducing their electricity consumption during grid emergencies.
PJM, which supplies electricity to about 67 million people across parts of the eastern and midwestern United States, said the grid has come under pressure due to soaring air-conditioning use, unexpected power plant outages and congestion on major transmission lines.
The grid operator also notified neighbouring electricity markets that power exports from its network could be reduced if necessary, allowing them to prepare for possible supply disruptions.
Electricity demand has risen steadily throughout the week as high temperatures persisted across the region. On Thursday, demand came close to the system’s all-time record, forcing PJM to activate expensive standby power plants after a sudden drop in generating capacity. No outages were reported.
Preliminary data showed electricity demand reached about 163 gigawatts on Thursday, just below the record of 165.6 gigawatts set two decades ago. The actual demand was lowered through demand response programmes that encouraged participating customers to reduce consumption.
Heat alerts remain in effect across most of PJM’s service area through Saturday, with parts of the Mid-Atlantic expected to remain under high temperatures into Sunday.
The strain on the grid also sent wholesale electricity prices soaring in some areas to more than $2,500 per megawatt-hour, compared with about $40 under normal operating conditions. Analysts attributed the spike to the high cost of transmitting electricity across congested power lines during periods of exceptionally high demand.
