Procurement Process Guide

The Grid Interconnection Process, Explained

Equipment lead time gets most of the attention, but for a lot of projects, the interconnection queue is the longer pole in the tent. Here's what actually happens between filing a request and energizing.

By Voltfield Editorial Team·Published August 2, 2026·Updated August 23, 2026·How we source & verify this

Key takeaways

  • Interconnection is a multi-stage study process run by the grid operator, and each stage can take months to years.
  • FERC Order 2023 moved queues to cluster studies, with readiness deposits and use-it-or-lose-it deadlines.
  • For many projects the queue, not equipment lead time, is the longer pole in the tent.
On this page · 6 sections
  1. The five stages, in order
  2. Cluster studies: the post-2023 reform
  3. How this varies by region
  4. Why most queued projects never get built
  5. Interconnection timeline vs. equipment lead time
  6. Frequently asked questions

Connecting a generation project — solar, wind, storage, or a new load — to the transmission or distribution grid isn't a permit you apply for once. It's a multi-stage technical study process run by the transmission provider or grid operator (a regional ISO/RTO like PJM, MISO, ERCOT, or CAISO, or a utility running its own queue), and each stage can take months to years depending on how congested the local grid already is.

The five stages, in order

Interconnection request
The developer files a formal request establishing queue position, along with a study deposit. This is the moment that starts the clock — and the position in line matters, because studies are often done in the order requests were filed (or in batches, see cluster studies below).
Feasibility study
A first-pass, relatively quick study estimating potential system impacts and a rough order-of-magnitude cost and timeline. It's meant to flag obvious problems early, not to be the final answer.
System impact study (SIS)
A detailed technical study of what the project actually does to the grid — thermal loading, voltage, stability, and short-circuit contribution — and identifies the specific network upgrades required to interconnect safely.
Facilities study
Detailed engineering and firm cost estimates for the specific interconnection facilities and network upgrades the system impact study identified — this is where a rough cost estimate becomes a real number the developer has to plan around.
Interconnection agreement (IA)
The executed contract: the developer commits to funding and often building the required upgrades, and the transmission provider commits to interconnecting the project once they're complete. This is the document that actually allows energization.

Cluster studies: the post-2023 reform

For years, most queues studied projects one at a time, in strict filing order — a project near the back of a long queue could wait years just for its turn to be studied, even if it was otherwise ready to build. FERC Order 2023 (2023) required transmission providers to move toward cluster studies: batches of interconnection requests studied together on a fixed cycle, paired with stricter readiness deposits and "use-it-or-lose-it" deadlines meant to push out speculative projects that were holding a queue position without a realistic path to construction.

Why this matters for procurement: a project's queue cohort and study cycle timing now matter as much as its position number. Two projects filed the same month in different regions can be on completely different timelines depending on how their transmission provider has implemented cluster reform.

How this varies by region

FERC Order 2023 only reaches transmission providers under FERC jurisdiction — PJM, MISO, SPP, CAISO, and NYISO among them — and each has implemented cluster studies on its own timeline and with its own specific rules. ERCOT sits outside FERC jurisdiction entirely and runs its own generator interconnection process, so its reform path and timelines don't automatically track the others. Comparing queue position across regions really means comparing different rulebooks, not just different backlogs — check the specific transmission provider's own process before assuming a timeline transfers from one region to another.

Why most queued projects never get built

Lawrence Berkeley National Laboratory's annual "Queued Up" report has tracked this for years: only a minority of projects that enter an interconnection queue ultimately reach commercial operation. Many withdraw once system impact study results show the required network upgrade costs, or after a competing project ahead of them in the queue claims the available capacity first. That attrition rate is exactly why queue position alone is a weak signal of whether a project will actually get built on schedule.

Interconnection timeline vs. equipment lead time

For a lot of projects today, the interconnection study-and-upgrade timeline runs longer than the equipment procurement timeline — even with transformer lead times stretching past 3 years. That reshuffles the usual planning order: instead of finalizing interconnection and then ordering equipment, both need to move in parallel from the earliest feasible point, with the equipment order placed against a preliminary spec rather than waiting for the facilities study to finalize every detail.

Frequently asked questions

What are the stages of the grid interconnection process?

In order: an interconnection request establishes queue position, a feasibility study gives a rough first look at impacts and cost, a system impact study identifies specific required upgrades (thermal, voltage, stability, short-circuit), a facilities study prices and engineers those upgrades in detail, and an interconnection agreement is the executed contract that obligates the developer to fund the upgrades and the transmission provider to interconnect the project.

What is a cluster study and why did it replace serial studies?

A cluster study evaluates a batch of interconnection requests together in one study cycle instead of one at a time in queue order. FERC Order 2023 (2023) required transmission providers to move to cluster studies with stricter readiness deposits and use-it-or-lose-it deadlines, specifically to address a backlog where projects had been waiting years for serial, one-by-one studies.

Why do most interconnection queue projects never get built?

Berkeley Lab's annual "Queued Up" report has repeatedly found that only a minority of projects that enter interconnection queues ultimately reach commercial operation — many withdraw once study results show the required network upgrade costs, or after competing projects ahead of them in the queue claim available capacity.

How does interconnection timeline compare to equipment lead time?

For many projects, interconnection studies and required network upgrades now take longer than procuring the generation equipment itself — which is why queue position and study milestones need to be tracked in parallel with equipment ordering from day one, not treated as a formality to clear after equipment is already on order.

Next steps

Once your interconnection facilities study specifies the equipment — GSU transformers, switchgear, protection relays — configure it directly on the Renewables or Data Centers reference and check its indicative lead time before you're locked into a facilities-study cost estimate. Tracking multiple studies and equipment orders across projects? The specification checklist keeps every vendor spec consistent, and the Lead-Time Index shows current equipment lead times to plan alongside your queue timeline.

Equipment

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Free to quote with attribution. Suggested citation: Voltfield Editorial Team, “The Grid Interconnection Process, Explained,” Voltfield, updated August 23, 2026. https://voltfield.org/guide-grid-interconnection-process.html

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