Eastern U.S. Electricity Demand Hits Multi-Year Highs Amid Heat Wave
Key Insights
Electricity demand in PJM Interconnection and ISO New England surged to multi-year highs on June 23 and 24, driven by a widespread heat wave across the Eastern U.S.
PJM Interconnection's peak load reached 160,560 MW, exceeding seasonal forecasts, while real-time wholesale prices spiked to $1,334/MWh due to increased reliance on natural gas and petroleum generation.
ISO New England recorded its highest demand since 2013 at 25,898 MW, with prices peaking at $1,110/MWh, supported by oil-fired plants, Canadian imports, and natural gas.
The heat wave highlighted grid resilience challenges, with petroleum generation in PJM tripling and New England's last coal plant, Merrimack, activated to meet demand.
Electricity demand in the PJM Interconnection and ISO New England, two of the largest regional grid operators in the Eastern United States, reached multi-year highs on June 23 and 24, respectively, as a relentless heat wave swept across the region. The surge in demand tested grid resilience and underscored the challenges of balancing supply during extreme weather events.
PJM Interconnection, the nation's largest wholesale electricity market, reported a peak load of 160,560 megawatts (MW) on June 23 between 5:00 p.m. and 6:00 p.m., surpassing its seasonal forecast of 154,000 MW. While this fell short of the 2006 record of 165,563 MW, the grid's expanded footprint—now covering 13 states and the District of Columbia—highlighted the strain. Real-time wholesale prices skyrocketed to $1,334 per megawatt-hour (MWh) at 7:00 p.m., a stark contrast to the $52/MWh peak recorded just a week earlier on June 16.
At peak demand, natural gas accounted for 44% of PJM's generation, followed by nuclear (20%), coal (19%), and solar (6%). Petroleum generation, typically reserved for high-demand scenarios, tripled compared to the previous day, reflecting the grid's reliance on costlier backup sources during crises.
The following day, as the heat wave moved eastward, ISO New England faced its own peak demand of 25,898 MW between 6:00 p.m. and 7:00 p.m. on June 24—the highest since 2013. Preliminary data showed real-time prices peaking at $1,110/MWh, up from $65/MWh the prior week. To meet demand, ISO-NE leaned heavily on natural gas (47%), electricity imports from Canada (12%), and oil-fired plants (12%). Notably, the region's last coal-fired facility, Merrimack in New Hampshire, supplied an average of 280 MWh, underscoring its role as a contingency resource.
The heat wave's impact on electricity demand and pricing highlighted the vulnerabilities of regional grids to extreme weather. While natural gas remains the dominant fuel source, the spikes in petroleum and coal usage revealed the limitations of current infrastructure during peak periods. Grid operators are now under increased scrutiny to enhance resilience and diversify energy mixes to mitigate future risks.