PJM (Pennsylvania-Jersey-Maryland grid operator) warns of heat wave and grid stress, signaling summer 2026 capacity constraints for datacenters.

The July heat wave that pushed PJM toward record electricity demand should force Virginia policymakers to confront an uncomfortable truth: the electric grid does not run on mandates, slogans, or wishful thinking. It runs on power that is available when people need it.

During this heat wave, PJM — the regional grid operator serving Virginia and all or parts of 12 other states and DC — came within striking distance of its all-time summer demand record. PJM's measured July 2 peak reached 162.3 gigawatts, just below the old 2006 record of 165.6 gigawatts. But about 6 gigawatts of demand had been shed through emergency demand-reduction programs. Add that curtailed load back, and underlying demand likely exceeded the old record.

That distinction matters. PJM avoided a crisis not because needed power was comfortably supplied, but because emergency tools shaved demand at the moment of greatest stress. Grid failure is no longer theoretical — the grid is operating near the edge.

Extreme heat drives air-conditioning and cooling demand. Add Virginia's booming data-center industry, especially in Northern Virginia, and peak demand becomes even harder to serve. But the most important lesson from the heat wave is that weather can lead to failure on both sides of the ledger.

The same heat dome that pushed demand toward record highs also suppressed wind generation. A heat dome is a high-pressure system that traps hot air. Under these conditions, air sinks, compresses, and warms, producing stagnant conditions that reduce wind output. Low wind generation intensified PJM's cost pressures during the heat wave. At peak afternoon times, PJM was getting more electricity from oil-fired generators than from wind—wind was not available at the scale and hour the grid needed it most. Installed wind capacity is not the same as firm capacity during a heat emergency.

Solar faces a similar problem. On hot, sunny days, solar can help reduce midday demand. But PJM's reliability problem extended into the late afternoon and evening, when buildings remained hot, air conditioners kept running, families returned home, and data centers consumed massive amounts of electricity. Solar cannot carry a hot evening peak alone. This is the classic "duck curve" problem: solar can help during the day, but the grid still needs dispatchable power when the sun fades and demand remains high.

Dispatchable power carried the system. PJM leaned on natural gas, coal, nuclear, oil-fired peakers, imports, and emergency demand response to keep the lights on. Generators ran at maximum output and idle plants came online, while operating reserves fell from about 22 gigawatts earlier in the day to about 5 gigawatts by evening. PJM avoided rolling blackouts only by taking emergency steps to stabilize the system.

PJM's "deploy all resources" order was issued for the Dominion, BGE, and Pepco zones—apparently the first time that tool had been used since it was added about a decade ago. The Mid-Atlantic region was operating under emergency procedures to pull every available megawatt into service. PJM was dispatching costly fossil-fuel plants, rerouting congested power flows, and managing heavily loaded transmission lines. Coal was providing up to about 22 percent of system supply during the week, while high-cost gas and coal plants met peak demand. The resources most often targeted by political climate mandates were the resources PJM needed most when reliability mattered.

Virginia needs an energy policy that understands the difference between energy that is occasionally available and energy that is available on demand. Nuclear plants provide steady baseload power. Natural gas plants can ramp up when demand surges. Coal and oil units, however disfavored politically, remain emergency backstops in tight conditions. Battery storage can only help for a limited number of hours and would need to be recharged during periods of lower demand or pricing to avoid recharging during high-priced demand surges.

This is where Virginia's data-center debate must become more honest. Data centers are not villains—they are part of the modern economy, and Virginia has benefited enormously from them. But they require massive amounts of reliable, around-the-clock electricity. Virginia cannot welcome the world's most energy-intensive digital infrastructure while simultaneously making it harder to build and operate the firm power plants needed to serve it.

There is an environmental irony. Virginia policymakers who oppose natural gas plants in the name of clean energy may be creating conditions that push data centers onto diesel backup generators during emergencies. If Virginia's choice is between modern, regulated natural gas generation serving the grid efficiently and emergency diesel generators scattered across data-center campuses during reliability events, the cleaner and more reliable option is obvious: build and permit the generation the grid actually needs. The irony extends to the emergency use of coal and oil units during this week.

The price signals during the heat wave were equally alarming. Virginia prices jumped from about $40 per megawatt-hour to more than $600 per megawatt-hour, with price spikes above $2,000 per megawatt-hour in Northern Virginia due to congestion.

The lesson is that renewables have little value in a heat dome event. Wind and solar can contribute some energy and solar can shave midday demand, but reliability is measured at the hour of greatest need, not in annual averages or political talking points. When PJM was tested, it turned to dispatchable energy, emergency operating procedures, demand response, federal emergency authority, and every available resource it could find.

A serious energy policy must begin with reality: extreme weather increases demand; high-pressure heat domes suppress wind; solar fades in the evening; data centers require constant power; and the grid must balance supply and demand every second of every day. Baseload and dispatchable generation are not relics. They are the foundation of reliability in a modern economy.

Virginia can have economic growth, data centers, cleaner energy, and reliable electricity—but not if it pretends intermittent resources alone can carry a record-breaking grid through a hot, windless evening. The path forward is energy abundance: preserve and expand nuclear, build more natural gas generation, strengthen transmission, and stop retiring firm capacity faster than reliable replacements can be built.

The grid has issued its warning. Virginia should listen.