PJM Orders Emergency Power Cuts as Heat Strains the Grid
With 67 million people's power on the line, PJM leaned on paid demand cuts and data-center curtailments to keep the lights on through the heat.
For a few hours on Friday, the wholesale price of electricity that keeps the lights on for 67 million Americans jumped from roughly $40 a megawatt-hour to more than $2,500.
That is what a grid under siege looks like in numbers. PJM Interconnection, the largest power-grid operator in the United States, ordered customers enrolled in its emergency demand-response programs to cut consumption on Friday as a prolonged heat wave, generator outages and overloaded transmission lines pushed the system toward its limit. The order fell on industrial and residential users who are paid, under contract, to slash usage when PJM declares an emergency.
Demand was closing in on records that have stood for two decades. PJM's figures put Thursday's peak load at about 163 gigawatts, within touching distance of the all-time high of 165.6 GW set during a 2006 heat wave, and that Thursday number was already held down by the cuts. "The alert was issued to increase reserves on the system and avert outages during peak demand around 6 p.m. EDT on Friday," PJM said.
The strain did not stay on trading screens. Cities across the Mid-Atlantic and Midwest scrapped Independence Day plans as the heat index climbed. Washington canceled its America's Independence Day Parade with the index forecast at 110 to 115 degrees, Philadelphia called off its main parade, and a delayed Boston fireworks display was among the events pushed back. Earlier in the week, Energy Secretary Chris Wright signed emergency orders letting PJM curtail data centers and other large users with at least 50 megawatts of demand, and temporarily waive some power-plant pollution limits.
Here is the part that outlasts the heat wave. That near-record demand did not come only from air conditioners. PJM has spent months warning that data centers and electric vehicles are adding load faster than new generation is coming online, and Friday was a live test of a system running on thin margins. When wholesale prices spike past $2,500, someone eventually pays, through capacity charges, higher summer bills, or the demand-response contracts that quietly kept Friday from becoming a blackout. For households, that arithmetic tends to surface later, on a bill, not on the day of the emergency.
PJM avoided the blackouts it feared on Friday. But a grid that has to pay factories to switch off and data centers to fire up their own generators just to survive a July heat wave is saying something plain about the decade of demand in front of it.
