24/06/2025
🔌⚡ Yesterday’s intense heat pushed electricity demand across the PJM power grid to staggering levels. At 6 PM, PJM, the grid operator that supplies power to Erie, PA and over 65 million people across 13 states and D.C., set a new all-time June record with a load of 161,120 megawatts. That just exceeds their forecasted amount for June 23rd at 161,000 MW.
If you take a look at the graphs from the past 30 days, the difference is clear. Yesterday pulled the most power by far, driven by widespread heat and the massive demand for air conditioning. When it gets this hot, the entire grid feels the strain.
To give some perspective: the highest summer load PJM has ever recorded was 165,563 MW back in 2006. This summer, the grid has about 179,200 MW of generation capacity available. That means yesterday’s demand brought us within about 15% of the grid’s absolute limits. In addition to that, they’ve secured about 7,900 MW of demand response capacity. These are pre-arranged agreements with commercial and industrial users who agree to reduce electricity use automatically when the system is under stress. When you think about how much infrastructure it takes to power homes, businesses, hospitals, data centers, and industry across 13 states and D.C., that’s an incredible amount of energy being pulled all at once.
Now, while demand was high, the supply mix tells another part of the story. Around 6 PM, total grid usage was hovering near 160 gigawatts. Of that, about 147 GW came from non-renewable sources, mainly natural gas, coal, and nuclear. Only around 20 GW came from renewables, with roughly 9.4 GW from solar and about 4.5 GW from wind. So despite how much renewable energy capacity is growing, the grid still leaned heavily on fossil fuels to meet yesterday’s surge.
All in all, yesterday was a powerful reminder of just how much strain extreme heat can put on our infrastructure. The grid held up, but only just. As the climate continues to warm and these kinds of heat events become more common, the stress on our energy systems will only grow. What we saw yesterday could be a glimpse of what normal looks like in the years ahead.