NYISO Interconnection at a glance
Quick facts | NYISO |
|---|---|
Who runs it | The New York ISO runs the grid and interconnection studies for New York State. FERC approves its rules, and the New York PSC oversees utilities and state large-load policy. |
Governing rules | NYISO’s FERC-approved tariff (Attachment HH for generators) and NYISO’s load interconnection procedures |
Generator study process | A two-phase cluster study. A 45-day application window and 70-day validation period are followed by Phase 1 (about 190 days), Phase 2 (about 270 days, which adds deliverability) and final decision rounds. |
Current clusters | The Transition Cluster, with more than 70 GW, is in final decisions, and results haven’t been published. The 2026 Cluster is under way, with 25 requests totaling 5.1 GW posted by early September 2026. |
Generator costs | A $10,000 non-refundable application fee and a study deposit of $100,000 to $250,000 depending on size. Readiness Deposit 1 is $4,000 per MW at Phase 1, Readiness Deposit 2 is the greater of that or 20% of Phase 1 cost estimates, and 100% of allocated costs is due at acceptance. |
Withdrawal penalties | 25% of the study deposit before Phase 1, then 50% of the study deposit plus 10% of Readiness Deposit 1, then 100% of the study deposit plus 20% of Readiness Deposit 2 in the final decision period |
Large load threshold for NYISO review | Loads over 10 MW connecting at 115 kV and above, or 80 MW or more below 115 kV |
How large loads connect | NYISO runs a reliability study, called a System Impact Study, but the load signs its interconnection agreement only with the utility. NYISO isn’t a party. |
Large load queue | 11.9 GW as of February 2026, up from about 1 GW in 2022 |
Large load rules status | Being reformed. NYISO’s draft framework, with firm, non-firm and zero-withdrawal service options, passed one NYISO committee and failed another in October 2026. A FERC filing is reportedly targeted for November 16, 2026. |
Peak demand, for scale | 31,097 MW on July 2, 2026, below the all-time summer peak of 33,956 MW on July 19, 2013 |
Last updated | November 3, 2026 |
NYISO Generator Interconnection Process
Generator interconnection,
step-by-step
NYISO studies generators in a two-phase cluster. Deposits rise at each decision point, and so do the penalties for leaving. Developers commit to Phase 2 before they know their deliverability results, which makes site choice especially important.
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Prepare and watch for the window. NYISO announces each cluster’s start date in advance, with a 90-day notice period before the application window opens. An optional pre-application lets developers talk with NYISO and the utility first.
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Apply during the 45-day window. Applications need models, a one-line diagram, a site layout, proof of site control, a $10,000 fee and a study deposit of $100,000 to $250,000 depending on size.
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Validation and engagement. Over 70 days, NYISO flags deficiencies, developers fix them, and NYISO and the utilities hold engagement meetings.
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Enter Phase 1. Developers have 5 business days to post Readiness Deposit 1, at $4,000 per MW, or withdraw. Phase 1 then studies the cluster’s local upgrade costs over about 190 days.
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Enter Phase 2. Developers have 10 business days to post Readiness Deposit 2, the greater of Readiness Deposit 1 or 20% of Phase 1 costs. Phase 2 adds deliverability analysis over about 270 days.
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Accept or reject cost allocations. In final decision rounds, developers accept their allocated costs by posting 100% as cash or security, or withdraw. NYISO reallocates costs after each round until a final round.
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Sign the agreement and build. Projects that accept sign an interconnection agreement with NYISO and the utility, then construction begins.
NYISO Large Load Interconnection Process
Large Load interconnection,
step-by-step
In New York, NYISO studies large loads for reliability, but the load signs its interconnection agreement only with its utility. NYISO’s review applies to loads over 10 MW connecting at 115 kV and above, or 80 MW or more below 115 kV. NYISO, the New York PSC and FERC are all working on new large-load rules, so confirm current requirements with your utility.
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Contact your utility. The utility that would serve the site is the starting point. Loads below NYISO’s thresholds follow the utility’s own process.
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Request a System Impact Study. The utility or customer asks NYISO for a reliability study, and the load enters NYISO’s queue.
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NYISO System Impact Study. NYISO studies the load’s reliability impact on the grid.
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Facilities study with the utility. The utility designs the connection and any upgrades.
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Reliability planning. The load is included in NYISO’s reliability planning studies.
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Sign the agreement with your utility. The customer and utility sign the interconnection and construction agreements, and NYISO isn’t a party.
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Energize. The utility energizes the load once its facilities and upgrades are complete.
What's changed recently in NYISO interconnection
Last updated November 2026
NYISO’s generator process is wrapping up its first cluster under the reformed rules, and large-load rules are being rewritten at three levels at once: NYISO, the New York PSC and FERC. If your project is in NYISO’s process or headed there, check which of these changes apply before your next deadline.
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February 2026: The New York PSC opened its Energize NY Development proceeding to define large loads, screen out speculative requests and make data centers bear the costs they cause. At the time, 11.9 GW of large load was in NYISO’s queue.
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June 18, 2026: FERC issued a show-cause order finding that NYISO’s tariff may lack a clear study process for transmission service to large loads, along with safeguards like forecasts and telemetry.
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Mid-2026: The Transition Cluster, with more than 70 GW, moved into final decision rounds after utility delays pushed its schedule back 60 days. Final results haven’t been published.
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September 2026: NYISO’s 2026 Cluster was under way, with 25 requests totaling 5.1 GW posted. NYISO also released a draft large-load framework with firm, non-firm and zero-withdrawal service options.
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October 2026: The large-load framework passed NYISO’s Business Issues Committee but failed its Operating Committee, with most members abstaining and some state agencies opposed.
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Coming up: a FERC filing on large loads reportedly targeted for November 16, 2026, final Transition Cluster results, and decisions in the PSC’s Energize NY Development proceeding.
How LandGate Helps with NYISO Interconnection
Quickly and accurately determine the feasibility of a site in NYISO using LandGate's nationwide data
Get your projects on the grid faster with reliable transmission data.
Pick a site before the cluster window
NYISO gives 90 days’ notice before a 45-day application window, and applications need proof of site control. Search parcels by criteria such as distance to a substation and available offtake capacity, and see available transfer capacity at transmission-level injection points to find points of interconnection worth applying for.
Commit to Phase 2 with confidence
Phase 1 results don’t include deliverability, and entering Phase 2 means posting at least 20% of Phase 1 costs. LandGate’s automated offtake capacity studies show substation details, capacity results, limiting elements such as transmission lines, and queue information, so you can spot upgrade risks before you're locked in.
Find capacity at the right voltage
NYISO’s review threshold drops from 80 MW to just over 10 MW for loads connecting at >115 kV, so voltage shapes which rules apply. LandGate shows the subtransmission grid (typically between 34.5 kV and 138 kV) with hosting capacity and ATC at the line level, and its Data Center Due Diligence Reports rank the closest substations by available capacity.
Lock down the best sites
NYISO requires proof of site control at application and again to enter Phase 2. LandGate pairs its grid data with proprietary landowner leads, nationwide ownership data and contact info, and a map-based CRM to help you find, secure, and track the right parcels, including off-market properties with the ideal infrastructure profile.
