All six of the United States’ regional grid operators reached a regulatory crossroads on August 17, when a Federal Energy Regulatory Commission deadline required each of them to either defend their existing tariffs for connecting large electric loads to the grid or propose concrete reforms. The proceeding directly shapes how AI data centers, heavy manufacturers, and EV charging depots gain access to transmission infrastructure.
What FERC ordered and why
On June 18, 2026, FERC issued a series of Federal Power Act Section 206 show cause orders directing organized market operators to justify or reform their existing rules relating to large load interconnection.
FERC issued six tailored show cause orders to each of the FERC-jurisdictional RTO/ISO entities and the jurisdictional transmission owners within each RTO/ISO to justify why their current tariffs remain just and reasonable in the absence of clear and consistent provisions for large load customers or, alternatively, to propose changes.
By leveraging its authority under Section 206 of the Federal Power Act, FERC contends that certain tariff provisions are unjust and unreasonable and accordingly compels each RTO to modify or add language to fully comply with the FPA.
The proceedings trace back to October 23, 2025, when the Secretary of Energy, acting under Section 403 of the Department of Energy Organization Act, directed FERC to consider an Advance Notice of Proposed Rulemaking focused on the timely and orderly interconnection of large loads to the interstate transmission system. The ANOPR defines large loads as electricity demand generally greater than 20 megawatts. FERC’s show cause orders apply specifically to loads with a peak demand in excess of 50 MW that interconnect to transmission lines greater than 69 kV.
The six operators in the crosshairs
FERC directed each RTO/ISO to explain how it intends to ensure that adequate generation will be available to serve existing and new large loads, with those generation adequacy reports due by July 20, 2026. The RTO/ISO and transmission owners then had 60 days from issuance, on or by August 17, 2026, to either show cause why their tariff remains just and reasonable without the identified reforms, or explain what tariff changes would remedy FERC’s concerns.
The six show cause orders are directed at each of the Regional Transmission Organizations and Independent System Operators and their constituent transmission owners: PJM Interconnection, Midcontinent Independent System Operator (MISO), Southwest Power Pool (SPP), California Independent System Operator (CAISO), ISO New England (ISO-NE), and New York Independent System Operator (NYISO).
Together, these operators govern the bulk of the nation’s interstate transmission grid. Their interconnection rules determine how quickly, and at what cost, new large electricity consumers can plug into the system. As EV fleet depots and high-power public charging hubs multiply, those rules are increasingly central to charging infrastructure planning.
The grid capacity pressures playing out at the transmission level are already filtering down to distribution networks. A $275 million rate hike in eastern Pennsylvania this July locked data centers into ten-year load guarantees before a single kilowatt-hour could flow, a sign of how congested grid connection pipelines are reshaping commercial terms at every voltage level.
FERC’s show cause orders reflect its preliminary view that current frameworks may be inadequate to address reliability, cost allocation, and timing challenges associated with large load growth. Industry observers expect the RTO responses to be the beginning of an extended proceeding rather than its conclusion.
EV charging caught in the queue
Heavy-duty EV charging is among the load classes most affected by slow interconnection rules. Charging hubs for electric semi-trucks and bus fleets routinely require megawatt-class grid connections that run through the same RTO study processes as industrial factories.
The constraint is no longer charger supply. Grid interconnection timelines, site power capacity, and payment system reliability now define the critical path for infrastructure scaling.
The queue problem is not hypothetical at the state level either. A Washington utility’s $3.2 billion grid expansion plan, now under review by state regulators, was built in part around projected load growth from electrification, underscoring how transmission and distribution investment decisions are being reshaped simultaneously by the same demand curve.
What comes next
FERC strongly encouraged RTOs/ISOs to file voluntary FPA Section 205 tariff revisions rather than waiting for further action, noting that this path provides the benefits of being first to wield the pen and a more favorable standard of review for the proponent. It will be critical for all interested parties to timely intervene and participate in FERC’s show cause order proceedings, as they will help shape the RTOs’ rules for data center and large load integration for years to come.
Chairman Laura V. Swett noted during the open meeting that FERC will leave the generic RM26-4 proceeding open to potentially address non-RTO utilities in the future.
Separately, on August 3, Senate Energy and Natural Resources Committee Ranking Member Sen. Martin Heinrich (D-N.M.) introduced the Guarding Ratepayers from Increased Demand-costs (GRID) Savings Act of 2026, which would create a process for large electricity users to pay for any infrastructure costs associated with their increased demand on the electric grid.
That bill, if enacted, would complement FERC’s interconnection reforms by addressing cost allocation, a question the show cause orders leave largely to each RTO’s own proposal.
FERC has indicated it could take additional action if RTO responses are found insufficient, meaning the August 17 filings mark the beginning of a proceeding rather than its conclusion.
