Large Load Resource Adequacy: What Six RTOs Told FERC

On July 20, all six grid operators filed their large load resource adequacy reports with FERC, the first deliverable from the Section 206 show-cause orders issued June 18. The reports answer one question: how does each region intend to keep enough generation online to serve the data centers it is already approving? Five operators described work already underway. ISO New England proposed something none of the others did.

New England’s answer is that new large loads should bring their own generation, and that the capacity market should stop buying capacity on their behalf. For anyone quoting transformers, switchgear, or protection into these regions, that pairing is the signal worth reading closely, because it decides whose purchase order the generation-side equipment lands on.

What ISO-NE’s BYONG Proposal Actually Says

ISO-NE told FERC that two related actions will be necessary. The first is requiring new large loads to bring their own incremental new generation, a requirement the region has started calling BYONG. The second is excluding those loads from the load-side requirements of the capacity market.

The reasoning starts from an unusual position. New England load has been flat or declining for a decade, the region has generally been long on supply, and ISO-NE told FERC it has not yet encountered significant large-load growth. FERC acknowledged as much, expressing less concern with ISO-NE than with other regions while still finding the tariff deficient. New England is writing rules ahead of the wave rather than cleaning up after one.

Under the proposal, large loads become responsible for bringing their own energy supply or accepting curtailment. ISO-NE said it intends to pursue rules modeled on SPP’s Conditional High Impact Large Load Service, which lets a large load take energy on a long-term non-firm basis, for up to seven years, before network upgrades or designated resources are in place. That mechanism took effect July 1. We covered CHILLS when FERC approved it in June, in the show-cause order analysis this piece follows.

Excluding Large Loads From the Installed Capacity Requirement

The second half is the sharper move and the one most likely to be misread. ISO-NE proposes to exclude new large loads from the system load forecasts used to set the capacity market’s demand curves and its Installed Capacity Requirement, so the market does not procure incremental capacity on their behalf.

This is not a decision to stop forecasting data centers. ISO-NE told FERC it has been working with transmission owners to develop protocols for tracking large loads and folding them into its forecasting processes. The exclusion is specific to one calculation, the one that sets how much capacity the region buys and bills to everyone. Planning still sees the load. The capacity market stops paying for it.

ISO-NE is alone in proposing this. NYISO continues to include large loads in its demand forecasts and planning process, and PJM is re-examining the role of its capacity market altogether. The divergence reflects a real disagreement about whether a capacity market should socialize the cost of integrating new large loads, and it means a distributor quoting across regions cannot assume one playbook.

Why New England is designing against that outcome is visible one region over. New Jersey’s Board of Public Utilities concluded in its July 15 Phase 1 report that distribution costs make up about 25% of the average residential bill in the state, ranging from 19% to 33% depending on the utility. The rest is supply and transmission, set at the federal and regional level. When large-load costs land in a capacity market, the state has no lever to pull.

What the Other Five Filed

The six large load resource adequacy reports diverge more than the shared deadline suggests. Each operator has its own docket, and each named its own filing dates.

Operator	Docket	Core proposal	Filing target
ISO-NE	EL26-72	BYONG plus Installed Capacity Requirement exclusion	Detailed rules in 2027
PJM	EL26-67	Reliability Backstop Procurement, plus a framework for periods of insufficient resource adequacy	July 31 and August 7, 2026
MISO	EL26-70	Zero Injection Generator Interconnection Agreement, plus a Large Load Parallel Study Process	July 31 and end of September 2026
SPP	EL26-68	Price Adaptive Load and Price Adaptive Load Service	On or before November 16, 2026
CAISO	EL26-71	Large Load stakeholder initiative as the compliance vehicle	November 16, 2026
NYISO	EL26-69	Planning and market reforms	Around March 2027

Two of these matter more to an equipment buyer than their names suggest.

MISO’s Zero Injection Generator Interconnection Agreement covers generation that serves only load at the same substation and never injects onto the broader transmission system. Because the machine cannot export, MISO expects to hold network upgrades to roughly the substation level. That is a materially smaller and faster interconnection than a full network study, and it is the cleanest description any operator has given of what a co-located generator actually has to buy. MISO’s companion Large Load Parallel Study Process would study loads of 250 MW or more alongside their associated generation, with generation nameplate capped at 150% of the identified load need, targeting roughly 120 days.

SPP is furthest along because it started earliest. Its High Impact Large Load rules define the trigger by voltage as well as size, at 10 MW or more at 69 kV and below, or 50 MW or more above 69 kV. That definition is worth knowing even outside SPP, since ISO-NE has now pointed at the SPP model as its template.

The Date Most People Have Wrong

There is a widely repeated assumption that the tariff rewrites land in mid-August. They do not, and getting this wrong will put a procurement calendar about a year early.

August 17 is the 60-day show-cause response deadline. On that date an operator either defends its existing tariff or proposes revisions. It is not the rule text. Operators were also allowed to request a limited abeyance, by August 3, of up to 90 days, and then file their proposed changes under Section 205 instead. ISO-NE has pointed to November 16 as the date for that filing, and it told FERC the detailed implementing rules for the capacity market exclusion arrive in 2027. CAISO and SPP have named November 16 as well. NYISO is targeting March 2027.

So the real sequence runs the other way from the headlines. The show-cause docket produces rule text late, while the operational filings that change what a project has to buy are happening now: SPP’s conditional service is already effective, and the PJM and MISO filings went in at the end of July. One more detail from the order deserves a place in any 2026 plan. FERC directed that the reforms be prospective only, and said the orders are not intended to disrupt existing commercial arrangements. A project already under contract is not being reopened.

What This Means for Equipment Buyers

Strip out the docket numbers and three consequences remain.

Generation-side equipment shifts onto the developer’s purchase order. A load required to bring its own supply is buying the generator step-up transformer, the medium-voltage paralleling switchgear, and the protection that lets a machine run matched to a load without exporting. That spend moves out of a utility rate base and onto a developer with a commissioning date, which is a different buyer with different urgency. It is the same shift we traced when load flexibility became an equipment spec, arriving now through resource adequacy instead of curtailment.

Cost-allocation firewalls do not suppress demand. Keeping a load out of the Installed Capacity Requirement protects existing ratepayers from a capacity bill. It does not remove one transformer from the order book. The iron still gets bought, by someone else, on a faster clock.

Public data is about to get better. FERC told ISO-NE to post large-load additions by pricing zone, planned network upgrades by type, and cost estimates for those upgrades, in one searchable and filterable place. For a muni or co-op without a market-intelligence budget, a public list of planned network upgrades is a planning input that did not exist before.

Which operator’s rules bind first, how the equipment categories tighten across those filing dates, and how to position a quote against a developer-funded order rather than a rate-based one: that is the work we do in the report library. The short version is that the show-cause docket is a 2027 story, and the filings that move equipment are already in front of FERC.

Our grid modernization procurement guide tracks the federal, RTO, state, and utility actions shaping the data center load class. The large load resource adequacy reports are the first coordinated read on how the regions intend to keep the lights on while they connect it.

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Related Reading

• FERC Large Load Interconnection Order: 6 RTOs on the Clock
• Data Center Load Flexibility Is Now an Equipment Spec
• PJM Capacity Auction Results: A Cap-Clear, No New Steel