Large Load Interconnection

Large Load Interconnection: what this is

On October 23, 2025, the Department of Energy invoked its rarely used § 403 authority to direct FERC to open a rulemaking on connecting large loads (data centers, AI, advanced manufacturing) to the interstate grid (Docket RM26-4-000), and asked for final action by April 30, 2026.

Rather than run a multi-year rulemaking, FERC answered on June 18, 2026 with six tailored § 206 show cause orders, one to each RTO/ISO. Each makes a threshold finding that the region’s tariff may be unjust and unreasonable for lack of clear, consistent large-load rules, then puts the market on a 30/60-day clock to defend the status quo or file a fix across the same five reform categories.

The through-line is cost causation made visible: the large load that triggers a network upgrade should bear its cost and spare ordinary ratepayers, with new transparency into how those costs are identified and allocated. The same morning, FERC issued Item E-2 (EL25-49-002), the order on rehearing that finalizes the rates and terms for the three new transmission services its PJM co-location proceeding created, the same services the six orders extend to every other region.

As of the August 3, 2026 sweep, all six markets have used the tools the clock gives them. Every RTO/ISO filed its 30-day generation-adequacy report by July 20 (confirmed on eLibrary for all six). Every one of the six proceedings now carries an abeyance motion: PJM and its Transmission Owners filed five days early, on July 28; the other five followed on August 3, the deadline itself. FERC opened an answer period on PJM's motion, and large stakeholders are answering in support rather than opposing it. August 17 still carries the six show-cause filings for any docket that isn't held in abeyance, plus PJM's separate request to extend its co-location compliance deadline. Running beside all of it, FERC opened the post-conference comment period on PJM's own governance on July 30, in Docket AD26-7-000, heading toward a September reform deadline.

The August 9, 2026 sweep finds the answer period producing the record's first real division. American Municipal Power is the lone opponent, arguing MISO's abeyance motion does not meet the show cause order's own abeyance standard, and asking FERC to condition further abeyance on a 20-day stakeholder proposal rather than deny it outright. Every other answer's own filed description states support for its docket's motion, from Constellation, an industrial customer coalition, the Corporate Energy Buyers Association, a state committee and state commissions; the one ambiguously worded exception (a state committee's answer in ISO-NE's docket) was confirmed as support by reading the filing directly. PJM's docket alone gained a third, separate abeyance motion, from a respondent asking FERC to rule by August 13 so it has certainty ahead of the August 17 deadline. Newly confirmed, known only through an Aug 4 Constellation answer that cites and dates them: the Indicated PJM Transmission Owners and, jointly, Exelon and FirstEnergy sought rehearing of both the PJM order and the E-2 order on July 20. Constellation's answer, opposing both, says the Exelon/FirstEnergy E-2 request largely repeats an earlier rehearing request the Commission already rejected. On the governance track, FERC's July 30 notice, once its own text was read directly, sets two concrete dates: post-conference comments are due August 21, and its Alternative Dispute Resolution forum is set to commence September 1. And PJM's capacity backstop moved from a stated intent to a proposed FERC filing on July 31 (Docket ER26-3380, not yet acted on): a one-time reliability auction targeting the same 6,831 MW shortfall, at a $555/MW-day cap and up to $20 billion. No docket has a FERC ruling yet on any pending abeyance motion.

Where things stand

Four proceedings and one context lane run beside each other, each on its own clock. Status as of 2026-08-09.

• The six-market §206 clock (FERC Dockets EL26-67-000 to EL26-72-000). The abeyance wave is now in its answer period, and it shows the record's first real division. American Municipal Power filed the lone opposition (to MISO's motion, Aug 7), arguing it fails the order's own abeyance standard and asking FERC to condition further abeyance on a 20-day stakeholder proposal. Every other answer's own filed description states support for its docket's motion instead. PJM's docket alone carries a third, separate abeyance motion, from Silver Run Electric (Aug 3), asking FERC to rule by Aug 13. Also newly confirmed, known only through Constellation's Aug 4 answer citing them: the Indicated PJM Transmission Owners and, jointly, Exelon and FirstEnergy sought rehearing or clarification of the PJM order on July 20; Constellation's answer opposes both. No docket has a FERC ruling yet on any pending abeyance motion. Next: 2026-08-17, Show-cause / tariff filings due (any docket not held in abeyance).
• PJM co-location: EL25-49 (FERC Docket EL25-49 (Item E-2, order on rehearing)). The same July 20 rehearing wave also targeted this order, known only through Constellation's Aug 4 answer citing them: the Indicated PJM Transmission Owners and, jointly, Exelon and FirstEnergy sought rehearing or clarification of the June 2026 Co-Location Order. Constellation's answer opposes both requests, says the Exelon/FirstEnergy request largely repeats arguments from a rehearing request the Commission already rejected against the December 2025 order, and asks FERC to grant Constellation's own pending rehearing request instead. That is separate from PJM's Jul 28 compliance-deadline extension request, still awaiting a ruling, and the Third and D.C. Circuit appeals of the December 2025 / February 2026 predecessor orders, still pending. Next: 2026-08-17, PJM and PJM TOs further compliance filing (if the extension isn't granted).
• PJM governance: AD26-7 (FERC Docket AD26-7-000 (Commission-led technical conference)). FERC set two concrete dates in its Aug 4 Federal Register notice: post-conference comments are due Aug 21, 2026, and its Alternative Dispute Resolution forum is set to commence Sept 1, 2026. The chairman's end-of-September deadline for a PJM reform package, or FERC imposing its own, remains a closing-remarks commitment with no calendar date yet noticed. A handful of comments, mostly from individuals, are already on the docket. Next: 2026-08-21, Post-conference comments due.
• The RM26-4 record (FERC Docket RM26-4-000 (the DOE §403 rulemaking)). Open with no dated next step. FERC answered the directive with the six §206 orders rather than a rule.
• Market context. PJM's capacity backstop moved from a stated intent to an actual FERC filing: on Jul 31 it filed the backstop auction plan (Docket ER26-3380), proposing a one-time reliability auction from Sept 30 to Oct 21 at a $555/MW-day cap, up to $20 billion, targeting the same 6,831 MW shortfall as the July 14 auction. More than 30 parties, from state commissions to a data center operator, have moved to intervene; no protests are on the docket yet. Next: 2026-09-30, PJM's one-time reliability backstop auction opens (Docket ER26-3380).

The six show cause orders

Each order has its own page below, with the quoted directives, the region-specific findings and the full respondent roster. Every PDF is a committed copy of the ferc.gov original, served with this site so page-precise citations open inline.

• E-7 PJM, Docket EL26-67-000: 195 FERC ¶ 61,211, 114 pp. Co-location rules already in place. Region: Mid-Atlantic / 13 states + DC. PJM is the control case, the one region that does not start from a blank page. FERC built PJM’s co-location rules in the parallel EL25-49 proceeding (finalized the same morning in Item E-2), so E-7 asks PJM to carry those new services (Interim NITS and Firm/Non-Firm Contract Demand) into a general large-load framework. The catch: every request still runs through one ‘first-ready, first-served’ clustered New Services Queue with no large-load-specific study, even though an Eligible Customer already pays ‘100% of the costs of the minimum amount of Network Upgrades’ its request triggers. So the order presses how to add flexible-load service and protect deals nearing completion without breaking that queue.
• E-8 MISO, Docket EL26-70-000: 195 FERC ¶ 61,212, 115 pp. Early-stage large-load rules. Region: 15 states, Midwest + South. MISO is the cost-allocation stress test. Its tariff still studies new load at its maximum demand ‘regardless of the load’s operational capabilities or willingness to be curtailed,’ and the resulting network upgrades are ‘rolled into the relevant transmission owner’s base zonal rates,’ spread across that utility’s wholesale customers. MISO itself told its Large Load Working Group the tariff does ‘not provide a consistent or transparent framework’ for large loads. E-8 presses whether flexible service and a pro forma cost-recovery agreement can keep those upgrade costs on the load that caused them.
• E-9 SPP, Docket EL26-68-000: 195 FERC ¶ 61,213, 92 pp. Most mature: HILL / HILLGA. Region: Central U.S., 14+ states. SPP is the benchmark, not the laggard. E-9 adopts SPP’s own ‘High Impact Large Load’ (HILL) definition, commends its ‘High Impact Large Load Generation Assessment’ (HILLGA) and Conditional HILL Service, and leaves the Attachment Z1/AQ/AX study stack and Highway/Byway cost split intact. Even in this leading framework FERC finds only two real gaps: no requirement to evaluate alternative transmission technologies, and no pro forma terms to ‘memorialize ongoing operational requirements in a transmission service agreement.’ The remaining ask is a mechanism to credit large-load payments back through transmission owners’ revenue requirements.
• E-10 CAISO, Docket EL26-71-000: 195 FERC ¶ 61,214, 118 pp. No Order No. 888 service. Region: California (+ WEIM footprint). CAISO is the translation problem. It ‘does not offer traditional Order No. 888 network and point-to-point transmission services, offers no firm, long-term transmission reservations of capacity,’ and its Participating TOs (not CAISO itself) ‘play the lead role in managing the interconnection of load’ inside California’s state planning and forecasting processes. So E-10 gives CAISO an alternative no other order offers: either build equivalent large-load protections, or explain why its single daily service and Transmission Access Charge (TAC/RAC) framework already solves the same cost and reliability problems.
• E-11 ISO-NE, Docket EL26-72-000: 195 FERC ¶ 61,215, 115 pp. Transmission-constrained grid. Region: Six New England states. ISO-NE is the small-system, big-load case. FERC flags a system peaking at only ‘30,000 MW’ with significant transmission constraints, and a ‘CELT load forecast’ that generally excludes proposed data centers, so a single large customer can move the regional needle. E-11 turns that into concrete planning questions: how Schedule 22/23 cluster studies, Pool Transmission Facilities at ‘69 kV’ and above, and the Monthly Regional Network Load behind-the-meter-netting rules should change, and whether to import PJM’s MW-threshold remedy for that netting.
• E-12 NYISO, Docket EL26-69-000: 195 FERC ¶ 61,216, 119 pp. Largely outside the tariff today. Region: New York State. NYISO is the tariff-gap case. It runs load interconnection for projects over 10 MW at ‘115 kV’ and above largely off-tariff: the study details, deposits, and assumptions sit in non-tariff documents, and its tariff ‘lacks a definition of large load’ as a category. With co-location reforms not expected until ‘2027,’ E-12 converts that off-tariff practice into show-cause issues: a 60-to-90-day study expectation, a new large-load definition with readiness requirements to deter speculation, and the only order’s express path to request a 90-day abeyance.

Decided the same morning: E-2 (Docket EL25-49-002, 195 FERC ¶ 61,209), the PJM co-location order on rehearing that finalises the three new transmission services the six orders extend.

The five reform categories

• Application & study processes (incl. alternative transmission technologies): Developing efficient transmission-service application and study processes, including consideration of alternative transmission technologies.
• Cost-shifting prevention & transmission-cost transparency: Preventing cost shifting and requiring transparency into transmission costs.
• Co-location arrangements & behind-the-meter (BTM) generation: Accommodating co-location agreements and behind-the-meter generation.
• New transmission services for flexible large loads: Providing new transmission services for flexible large loads.
• Studying generation serving electrically proximate / co-located loads: Developing a process to study generating facilities that serve electrically proximate large loads and co-located loads.

The §206 procedural clock

All six §206 orders run one clock from the June 18, 2026 issuance. The periods are stated in each order’s ordering paragraphs; the calendar dates are derived and business-day-adjusted (National Law Review). Status is computed from today’s date, not from confirmed filings, so it tracks the schedule rather than who has filed.

• 2026-07-09, Motions to intervene (21 days from issuance, Ordering ¶ (D) · Rule 214): Notices of intervention or motions to intervene in the six proceedings are due.
• 2026-07-20, Generation-adequacy report (30 days from issuance, Ordering ¶ (C)): Each RTO/ISO files an informational report on how it will ensure adequate generation to serve existing and new large loads.
• 2026-07-20, Requests for rehearing (30 days from issuance, FPA § 313(a)): Statutory deadline to seek rehearing of the June 18 orders before a court appeal.
• 2026-08-03, Abeyance requests (45 days from issuance, All six orders (e.g., E-12 P 42)): Deadline in each of the six orders to request full or partial abeyance (up to 90 days) of the proceeding. FERC says it will not grant abeyances reflexively and views extension requests with great disfavor.
• 2026-08-17, Show cause or file tariff changes (60 days from issuance, Ordering ¶ (B)): Each RTO/ISO and its Transmission Owners must show cause why the tariff remains just and reasonable, or file remedial tariff changes.
• Not yet dated, Response window opens (filing + 30 days, Ordering ¶ (E)): Interested entities may respond on whether the tariff remains just and reasonable and, if not, what replacement rates to implement. Opens once the show-cause/tariff filing is made.

This is an independent analysis microsite and is not affiliated with FERC or DOE. Order record as of 2026-06-22; commentary 2026-06-29; news and filings swept 2026-08-09. A machine-readable index for agents is at llms.txt.