Which ISO Has the Fastest Interconnection Timeline in 2026?
Short answer: On paper, the Southwest Power Pool (SPP) has the fastest interconnection timeline in 2026. Its new Consolidated Planning Process targets a signed generator interconnection agreement 180 days after the queue window closes. That target is still untested, though. SPP doesn't expect the first agreements from its transitional cycle until spring 2027.
ERCOT is the other standout. It doesn't run an annual cluster window at all, so projects can apply any time. ERCOT puts the full path to commercial operation for large generators at about 18 to 30 months. At the other end, PJM's reformed Cycle process runs about 690 days from its application deadline to a final agreement. That is the longest published target of the seven ISOs.
Below, we compare all seven ISOs using their own published timelines, then cover the fast-track programs that can beat the standard process. Every number comes from the step-by-step LandGate interconnection guides, which map each ISO's process for both generators and large loads. This ranking covers generators, such as solar, wind, storage and gas plants. Large loads like data centers go through separate processes with their own timelines, and in Texas they are currently on hold (more in the ERCOT section).
Interconnection Timelines by ISO: 2026 Rankings at a Glance
Rank | ISO | Process | When you can apply | Published target |
1 | Consolidated Planning Process | Once a year (Dec 15 to Feb 15 in the tariff) | 180 days from window close to signed agreement | |
2 | Individual studies, connect-and-manage | Any time | 18 to 30 months to commercial operation | |
3 | Scored, zone-based cluster | Once a year (Oct 1 to 15) | About 360 days of study phases, then the agreement | |
4 | Cluster study | 45-day windows | About 420 to 600 days of study phases, then the agreement | |
5 | Definitive Planning Phase (DPP) | Once per annual cycle | About 505 days from study kickoff to signed agreement | |
6 | Two-phase cluster study | 45-day windows | About 580 days through the final decision period, then the agreement | |
7 | Reformed Cycle process | Once per Cycle | About 690 days from application deadline to final agreement |
The CAISO, ISO-NE and NYISO figures add up each ISO's published phase timelines. The others are the ISO's own end-to-end figures.
ISO Interconnection Timeline Comparison
To compare each ISO’s interconnection timeline, we used each ISO’s official targets from tariffs, manuals, and filings as of October 2026, reflecting stated timelines rather than historical averages (which have often been longer). Timelines were measured from the application window closing to a signed interconnection agreement, using published end-to-end figures or the sum of individual phase timelines where necessary. Exact comparisons are limited because most ISOs accept applications annually, meaning a missed window can add up to 12 months, and ERCOT reports timelines to commercial operation rather than a signed agreement.
1. SPP: 180 days to a signed agreement (target)
SPP replaced its old DISIS process with the Consolidated Planning Process, approved by FERC in March 2026. Projects apply in a single annual window with 100% site control and financial security, then go through one 180-day Interconnection Cluster Study. A single 20-business-day decision point follows, where developers commit or withdraw.
SPP's 180-day target compares with a minimum of 12 months under DISIS and a historical median of 51 months. The catch is timing: first agreements from the transitional cycle are expected in spring 2027, and SPP had not confirmed some window dates and GRID-C rates as of October 2026.
Fast tracks: SPP's Expedited Resource Adequacy Study (ERAS) was a one-time, parallel study for projects nominated by load-serving entities facing resource adequacy shortfalls. About 13 GW was under consideration as of February 2026. Surplus interconnection service is also available: it lets a new resource, often storage, use unused capacity at an existing plant's point of interconnection, and requests are studied as they come in.
2. ERCOT: 18 to 30 months to commercial operation
ERCOT is the only ISO here without a cluster window, so projects enter the process whenever they're ready. For projects of 10 MW or more, a security screening study comes first, followed by a Full Interconnection Study run by the transmission service provider. Developer guides report that the screening takes up to 90 days and the full study about 40 to 300 days.
ERCOT's published range of 18 to 30 months runs all the way to commercial operation, excluding construction and supply delays. No other ISO publishes a target that far down the line. The trade-off is that ERCOT connects projects without building transmission to guarantee their output, so a connected project can still be curtailed.
Data centers face a separate hold. These timelines cover generators. Data center large loads are a different story. On August 3, 2026, Governor Greg Abbott directed the PUCT and ERCOT to audit every data center in ERCOT's interconnection process before any more could move forward, and ERCOT paused its Batch Zero large-load classifications in response. On September 21, he directed TCEQ to stop issuing data center permits until the audit is done.
The November 2026 election adds another variable. Democrat Gina Hinojosa defeated Abbott in the November 3, 2026 governor's race and takes office in January. She campaigned on a temporary moratorium on new data centers until the Legislature passes new protections, along with an end to data center tax breaks. How and when the current pause ends now depends on the incoming administration and the Legislature, and no end date has been set.
Faster path for small projects: Projects under 10 MW follow ERCOT's small generation process, which takes about 8 to 12 months, excluding construction and supply delays.
3. CAISO: about 360 days of studies
CAISO accepts applications from October 1 to 15 each year and scores them to decide which enter the study. In Cluster 15, only 145 of 541 applications made it in. Admitted projects then go through a 90-day engagement window, a Cluster Study with its report due within 150 days, and a facilities study planned for 120 days.
The agreement follows CAISO's annual Transmission Plan Deliverability allocation, which can add time. For Cluster 16, which closed October 15, 2026, CAISO expects the Cluster Study to start in January 2027.
Fast tracks: CAISO's Fast Track lets eligible smaller projects apply any time of year and go through screening instead of the cluster. Surplus interconnection service lets a new resource, often storage, use unused capacity at a plant that already has an agreement.
4. ISO-NE: about 420 to 600 days of studies
ISO-NE moved to a cluster process under Tariff Schedule 22, effective September 1, 2026. Its first regular window opened October 5 and closes November 19, 2026. After a 60-day engagement window, ISO-NE must report to FERC if the Cluster Study runs past 270 days. A facilities study follows, taking 90 days for a ±20% cost estimate or 180 days for ±10%, with a possible 90-day restudy before it. The agreement comes after that.
Fast tracks: ISO-NE has no expedited study track, but surplus interconnection requests are studied outside the cluster, so they don't wait for the next window.
5. MISO: about 505 days from kickoff to agreement
MISO's Definitive Planning Phase has three study phases, each ending in a decision point, followed by agreement negotiation. MISO targets about 140, 80 and 135 days for the phases and about 150 days for the agreement, roughly 505 days in total. MISO notes that actual cycles have rarely hit this target.
The wait before kickoff matters too. MISO's July 2026 working-group minutes list a DPP-2026 application deadline of September 10, 2026 and a study kickoff of December 9, 2026, though other trackers show a January 15, 2027 deadline. Queue caps can also push projects to a later cycle: the East (ITC) region's cap was already met for DPP-2026 as of June 2026.
Fast tracks: MISO's Expedited Resource Adequacy Study (ERAS) targets an expedited agreement about 90 days after its quarterly kickoff. Projects need 100% site control and written regulator verification of resource needs. ERAS is limited to 68 projects, about 10 per quarter, and sunsets by August 31, 2027.
6. NYISO: about 580 days through the final decision
NYISO runs a 45-day application window, a 70-day validation and engagement period, then two cluster study phases. In the Transition Cluster, Phase 1 was set at 190 days and Phase 2 at 270 days. Developers then accept or reject their cost allocations in final decision rounds, starting with a 30-day window, before signing the agreement.
Delays at one utility pushed the Transition Cluster's Phase 2 decision back 60 days, and NYISO had not published final results as of October 2026.
7. PJM: about 690 days to a final agreement
PJM's reformed Cycle process has an application review of at least 90 days, three System Impact Study phases of about 120, 180 and 180 days, and a 30-day decision point after each phase. Final agreement negotiation takes about 60 days. PJM itself puts the full process at roughly 690 days from the application deadline.
Scale is part of the story. Cycle 01 Phase I began September 28, 2026 with 633 projects totaling 168.6 GW. Each Cycle's later phases also wait for the previous Cycle to clear its milestones, so delays carry forward.
Fast tracks: PJM's Expedited Interconnection Track (EIT) targets a signed agreement about 10 months after a complete request. It is open to up to 10 projects per year, each at least 250 MW of unforced capacity, sponsored by a PJM state and located in it. EIT took effect July 31, 2026 and sunsets December 31, 2027. Surplus and replacement generation interconnection service offer other routes at existing plant sites.
What This Means for Developers
The fastest published target isn't always the fastest path for a given project. Three factors often matter more than the headline number.
Window timing. Every ISO except ERCOT studies projects in batches. Applying just after a window closes can add close to a year before your study starts, which can erase the gap between a fast ISO and a slow one.
Targets versus track record. SPP's 180-day target is new and untested, and MISO notes its cycles have rarely hit their targets. Treat every number in this post as a best case.
Your site. Upgrade costs, queue caps and congestion at your point of interconnection can stall a project in any ISO. In CAISO, scoring decides whether you're studied at all. Picking the right location matters as much as picking the right ISO.
Map Your Path Through Any ISO
LandGate's interconnection guides turn each ISO's process into a clickable map for both generators and large loads. Pick a region, then select any step to see what happens there, what it costs, how long it takes and what can stop a project.
Ready to find sites with the best shot at a fast interconnection? Contact us to book a demo to see how LandGate's grid and land data fit together.
Frequently Asked Questions
Which ISO has the fastest interconnection process in 2026?
SPP has the fastest published target: 180 days from the close of its queue window to a signed interconnection agreement. Its first agreements under the new process are expected in spring 2027, so the target hasn't been proven yet.
Which ISO has the slowest interconnection process?
PJM has the longest published target of the seven ISOs, at roughly 690 days from its application deadline to a final agreement.
How long does ERCOT interconnection take?
ERCOT puts the process for generators of 10 MW or more at about 18 to 30 months to commercial operation, not counting construction or supply delays. Projects under 10 MW take about 8 to 12 months. Data center interconnection in Texas is a different story: Texas large loads are on hold while ERCOT completes its data center audit, and the state has paused data center permits until then.
Why doesn't ERCOT have an interconnection queue window?
ERCOT studies generators individually as they apply instead of in annual clusters. It connects projects and manages congestion in real time rather than building transmission to guarantee each project's output.
What is the fastest way to interconnect in PJM?
PJM's Expedited Interconnection Track targets a signed agreement about 10 months after a complete request. It is limited to 10 state-sponsored projects per year of at least 250 MW and ends December 31, 2027.
Do ISOs actually meet their interconnection targets?
Often they don't. MISO notes its cycles have rarely hit its roughly 505-day target, and NYISO's Transition Cluster was delayed by 60 days at Phase 2. Published targets are best-case timelines.
