FERC clears SPP to wire data centers that agree to go dark in emergencies

FERC clears SPP to wire data centers that agree to go dark in emergencies The CHILLS tariff lets Southwest Power Pool connect large loads faster by making them interruptible, a template other grids straining under data-center demand will watch. The Federal Energy Regulatory Commission on Friday (2026-06-05) approved Southwest Power Pool's plan to connect data centers and other large loads on the condition that they accept being curtailed during grid emergencies.⁵ Interconnection queues, not generation, are now the binding constraint on US power growth. Under the tariff, branded "conditional high impact large load service," or CHILLS, SPP can cut service to those loads when the transmission system is constrained or under emergency conditions, according to FERC's decision. The regulator found the arrangement "just and reasonable and not unduly discriminatory or preferential."⁵ The logic is straightforward. A load that promises to disappear when the grid is tight imposes far less firm capacity obligation than one that demands round-the-clock supply. That lets the operator connect it against existing headroom instead of waiting years for new wires and firm resources. SPP gets demand growth without the reliability bill that growth normally carries.⁵ It also reframes the data center as a grid asset rather than only a grid burden. A curtailable hyperscale campus behaves, in emergency hours, like demand response at industrial scale. The trade-off sits with the operator: cheaper, faster hookups in exchange for power that is not firm when it matters most.⁵ The timing is not incidental. US regional grid operators have asked FERC for more time to upgrade existing transmission to lift capacity, after the commission in late 2021 directed the six major operators outside Texas to set up programs to do so.³ The infrastructure is lagging the load, and CHILLS is one way to square that gap without conceding reliability.³ The demand picture explains the urgency. PJM Interconnection, the largest US grid operator, has projected summer peak demand in the Dominion Energy zone covering Northern Virginia's Data Center Alley to grow 5.4% a year over the next decade.¹ Because hyperscale sites run continuously at high load factors, they lift winter peaks too, at a roughly 4% annual clip.¹ That is the kind of curve no transmission build-out comfortably keeps pace with. The money is moving in the same direction. NextEra Energy has agreed to buy Dominion Energy in an all-stock deal valued at $66.8 billion, the largest power utility acquisition on record, creating a regulated utility serving about 10 million customer accounts across Florida, Virginia and the Carolinas.^1,2 The enterprise value, including debt, tops $400 billion.¹ Capital is consolidating around the grids where data-center load is concentrated. For SPP, CHILLS is a way to say yes to that load faster. The pitch to a developer is access: connect sooner, accept that your service can be interrupted in the worst hours, and skip the multi-year wait for firm capacity. Whether enough developers take the deal is unclear, since interruptibility cuts against the uptime guarantees that hyperscalers sell to their own customers.⁵ There is a reliability angle too. NERC, in its Summer Reliability Assessment, has pressed operators to review seasonal operating plans and protocols for resolving potential supply shortfalls.⁴ A tariff that lets grids lean on curtailable load shifts some of that burden onto contractual interruption rather than spare megawatts, and it has not yet been tested in a real emergency.⁴ FERC's willingness to bless conditional, interruptible service for large loads gives other regional operators a template, and several are wrestling with the same data-center surge against the same lagging transmission.^5,3 SPP went first. PJM, with the heaviest concentration of data-center demand in the country, is the grid where a similar mechanism would matter most.¹ What to watch is adoption. The tariff's value depends on how many large loads actually sign up to be curtailable, and on whether the first invocation of those curtailment rights, when it comes, holds up operationally and legally. Until a grid emergency forces SPP to pull the trigger, CHILLS is a contract, not yet a proven tool.^5,4