All Six U.S. Grid Operators Are Rewriting How Big Loads Connect

Federal regulators have put the rules for connecting large electrical loads to the transmission system under simultaneous review in every organized U.S. market, and the first round of public comment closes Sept. 16.

On June 18, the Federal Energy Regulatory Commission issued six show cause orders under Section 206 of the Federal Power Act, one to each jurisdictional grid operator: PJM Interconnection, the Midcontinent Independent System Operator, Southwest Power Pool, the California Independent System Operator, ISO New England and the New York Independent System Operator. The orders, docketed EL26-67 through EL26-72, carry a preliminary finding that the operators' existing tariffs are unjust and unreasonable as applied to large loads. FERC defined a large load as a commercial or industrial customer with peak demand above 50 megawatts interconnecting to transmission lines greater than 69 kilovolts. That is the size and voltage class of a hyperscale data center campus, a large semiconductor fab, or an electric arc furnace.

The orders name five areas each operator must fix or defend. Study processes must run on defined timelines, with FERC pointing to windows of 60 to 90 days and requiring operators to evaluate alternative transmission technologies or explain why they were not used. Cost recovery agreements must include minimum financial contributions and credit support so that a customer who reserves capacity and never builds does not leave the cost with everyone else. Co-location rules must be spelled out, including a prohibition on netting behind-the-meter generation against demand charges. Operators must develop transmission services for loads able to reduce consumption during system stress, and set study procedures for generation serving electrically proximate load.

The schedule is what makes this a September story. Resource adequacy reports were due July 20, and operators could request an abeyance of up to 90 days by Aug. 3. Full responses, with proposed tariff language, were due Aug. 16, and interested parties get 30 days to comment, closing Sept. 16. Operators that took the extension file by mid-November, with comments due in mid-December. MISO is on the later track, its complete response due Nov. 16.

PJM's board issued a decisional letter on July 27 laying out what the operator intends to put in front of FERC. It includes a mandatory registry of large load customers whose electricity may be curtailed during system stress, compensation for those customers when they are directed to reduce consumption, a reliability backstop procurement, and an interim resource adequacy service effective June 1, 2027 for new large loads without sufficient capacity behind them. PJM's earlier board letter, issued Jan. 16, set the trigger at 50 megawatts of load at a single point of interconnection and noted that the 2027/2028 capacity auction cleared 5.6 percent short of the target reserve margin. MISO differs on details that matter to a jobsite: charging a storage resource does not by itself make a customer a large load, roughly 30 gigawatts of existing capacity stays under the older rules, and loads taking its flexible service face curtailment for reliability only, not to manage congestion costs.

The demand behind all of this is documented. The Energy Information Administration's 2026 Annual Energy Outlook found servers accounted for about 7 percent of commercial sector electricity consumption in 2025 and projected that share reaching 22 to 33 percent by 2050. EIA also put data center floorspace cooling at roughly 2.9 times the energy intensity of other commercial floorspace, which is why the mechanical load on these projects is itself a substantial electrical scope.

What changes on the job is the hardware behind the word flexible. A tariff that pays a facility to drop load during system stress, and penalizes it for failing to, turns curtailment from an operating preference into a contractual obligation with equipment attached. That means load-shed schemes in the switchgear, automated transfer and paralleling controls, generation able to pick up defined blocks on a defined timeline, revenue-grade metering a utility will accept, and a power monitoring system that can prove performance after the fact. Someone has to install, commission and periodically test the equipment behind the promise.

The co-location provision carries its own consequence. Barring the netting of behind-the-meter generation against demand charges changes where meters go and how the point of interconnection is drawn, and with it the medium-voltage scope on the customer side of the fence. Contractors bidding co-located generation work are pricing to rules being rewritten in the same quarter as the bid.

For the electrician, the near-term effect is on timing rather than technique. Interconnection rules gate energization dates, and energization dates gate when a contractor staffs up. Study windows of 60 to 90 days compress the front end and push more work into a shorter build window, favoring contractors with medium-voltage crews already assembled over those recruiting after the notice to proceed. Commissioner Chang, concurring in the PJM order, stated the commission's concern plainly: "We should not create unjustified costs for consumers in our efforts to connect and serve large loads." Cost allocation decided in these dockets determines which projects finance, and financed projects are the ones that hire.

The licensing and career consequence points where it has for two years. Work above 69 kilovolts, customer-owned substations, protective relaying and controls integration are moving from specialty niches toward the center of commercial practice on large-load sites. A journeyman card qualifies an electrician for the building; medium-voltage terminations, NFPA 70E arc flash competency and switchgear commissioning experience qualify them for the yard.

Six tariffs are being rewritten at once. The scope of work on the next generation of large-load projects is being drafted inside them.