PJM wants data centres to stop disconnecting when the grid wobbles

After nearly 4,000 megawatts of Virginia data centre load vanished in one event, the mid-Atlantic grid operator is drafting a binding rule to keep big new customers connected.

14 September 2026 · 6 min read · L1 Power and land · The Pulse, 10 September 2026

In this story: PJM

What happened

PJM, the grid operator that manages electricity for 13 states and Washington DC, told members of its own Planning Committee on 8 September that it will propose a new reliability standard requiring very large electricity customers, mainly data centres, to keep running through brief disturbances on the grid instead of automatically disconnecting. PJM described the proposal in its own post two days later. The move responds to an 18 June order from the Federal Energy Regulatory Commission, in docket EL26-67-000, which gave PJM and five other regional grid operators 60 days to either justify their existing rules for large loads or propose changes. PJM plans to file its actual proposed rule with FERC in November.

Why it matters

PJM says the immediate trigger was an event on 22 July, when it says nearly 4,000 megawatts of data centre load in northern Virginia unexpectedly disconnected from the grid at once, switching over to backup generation. PJM and the Virginia utility Dominion Energy then had to manage the sudden mismatch between how much electricity was being generated and how much was actually being drawn, along with the voltage and frequency swings that come with a change that large happening all at once. PJM's own post calls this the third separate measurable event in the last two years, meaning it has happened often enough that PJM is treating it as a pattern rather than a one-off. The timing adds to the pressure. PJM's own July capacity auction, the market where it buys the power supply cushion it needs for future years, cleared at 325 dollars per megawatt-day, the maximum price allowed, and 5.6 percentage points below PJM's own target reserve margin. A grid already buying its safety cushion at the price ceiling arguably has less room to absorb a sudden multi-gigawatt swing than one with ample spare capacity. PJM's own materials do not draw that connection; that last sentence is our reading of the two facts side by side.

What would change it, and when

Nothing is binding yet. PJM says it plans to file its specific proposed tariff changes with FERC in November 2026. FERC would then need to review and approve those changes before they carry legal force, a process with no fixed timeline in what PJM has published so far. PJM held an educational session for stakeholders on 15 September specifically about the large-load ride-through proposal, ahead of the formal filing.

What we do not know

PJM's own post does not name the specific data centre, data centres, or companies involved in the 22 July disconnection, so it is not possible to say from this document whose equipment tripped. It also does not give a date for when FERC might act after the November filing, or say precisely what the rule would require operators to install or change, beyond the general description of riding through disturbances. It is not yet clear how PJM's proposal will compare with what the other five regional grid operators, MISO, SPP, CAISO, ISO-NE and NYISO, come back with in response to the same FERC order, since each is handling its own filing separately.

What this changes for you

Nothing changes today for anyone's electricity bill or for a data centre's operations. This is a proposal, not a rule. But PJM's territory covers 13 states and Washington DC, and if FERC eventually approves something like it, large data centres there would face a legal requirement to keep operating through minor grid disturbances rather than relying on automatic disconnection as a safety default. Meeting that requirement is likely to mean new equipment or engineering costs for data centre operators, costs that could over time show up in what those operators pay to connect to or use the grid, though PJM's materials so far do not say who would ultimately bear them.

Sources

Everything above is written from these. Each line says what that document proves.

1. insidelines.pjm.com: PJM's own account of the 8 September proposal, the 22 July event, and the FERC docket and November filing timeline.
2. ferc.gov: FERC's own press release establishing docket EL26-67-000 and the 60-day deadline that prompted PJM's proposal.
3. pjm.com: PJM's own capacity auction results report, already on this site, source for the $325 per megawatt-day clearing price and the reserve margin figure used for context.
4. utilitydive.com: Independent reporting, already on this site, on a Pennsylvania regulator's vote to study data centre costs and curtailment inside PJM's footprint the same week. Context for the pressure PJM's territory is under, not confirmation of the 22 July event itself.

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