DOE clears PJM to curtail data centers as the largest US grid edges toward shortfall
A 18 May emergency order lets the operator cut large loads before rolling blackouts; PJM warns the 2026 summer leaves little reliability margin
Summary
DOE issued an emergency order on 18 May 2026 authorising Pjm, the largest US grid, serving 67 million people, to curtail data-center and other large loads with backup generation as a last resort before rolling blackouts during heat events. PJM warned that projected generation outages plus forecast demand "raise a significant risk of emergency conditions." Summer 2026 leaves only a thin reliability margin; for the first time the operator could not secure enough promised capacity across the whole region. PJM projects peak demand up 32GW by 2030, all but 2GW from data centers, with the region potentially below reliability standards from June 2027. The move follows record capacity-auction costs.
By the numbers
- 18 May 2026, DOE emergency order date.
- 67 million, people served by PJM.
- +32 GW, projected peak-demand growth 2024-2030 (30GW from data centers).
- Summer 2027, PJM's projected onset of capacity shortfall.
- 6 GW, modelled shortfall some analysts attach to 2027.
Why it matters
For the first time the US's biggest grid is rationing-ready: AI load is colliding with stalled generation buildout, and the operator now has explicit federal cover to cut the very data centers driving demand. It is the clearest sign that compute growth has outrun physical Electricity supply.
What to watch
- Whether any curtailment is actually invoked during 2026 heat waves.
- The 2027 capacity-auction clearing price and reliability margin.
- New generation and large-load tariffs entering service before 2027.