What is a grid interconnection queue?

A project enters a generator interconnection process when it asks a transmission provider to connect a producing facility to the grid. The provider models the proposed injection, checks equipment and network effects, identifies required upgrades, and develops an agreement. Berkeley Lab’s Queued Up methodology describes these as requests from power plants seeking transmission connection. Its dataset excludes distribution-connected projects, behind-the-meter projects, and load requests.

Consider a planned solar plant that can export 200 MW at a particular substation. The study asks what the grid does when the plant injects that power under different conditions, whether lines or protection need work, and how the connection interacts with other planned generation. A battery request adds charging and discharging assumptions. FERC Order No. 2023 specifically requires storage studies to use assumptions reflecting proposed charging behavior.

The word “queue” can mislead because it sounds like a single national line. In practice, each grid operator and utility administers its own requests under applicable tariffs. A project number is useful inside that process; it is not a nationwide ranking. Nor does entry mean approval. A request can move through studies, be withdrawn, receive an agreement, and still wait on permits, equipment, or construction before producing electricity.

The provider first decides whether the request is complete under its rules. The engineering work then evaluates the proposed point of interconnection, the generating equipment, power flows, short-circuit behavior, stability, and any effects on neighboring systems. A facilities study turns identified changes into a buildable connection scope. FERC’s interconnection explainer describes a cluster study followed by a facilities study and an interconnection agreement under its revised generator procedures.

Imagine two new plants on the same constrained line. A study of only one would miss the combined injection. If one project withdraws after results are issued, the provider may have to revisit assumptions and cost allocation for the rest of the cluster. The 2023 rule includes restudies for materially changed clusters and methods to allocate shared study and network-upgrade costs. A queue entry therefore contains both engineering work and commercial exposure.

The regional implementation matters. MISO’s generator-interconnection page describes milestone checkpoints, including technical information and proof of site control. CAISO’s request-and-study page provides its own cluster resources and timelines. A developer should read the operator’s current cycle rules and data requirements before interpreting a generic diagram as a filing guide.

Historically, many generator processes studied projects serially, roughly in arrival order. An early timestamp could put a project ahead for study and shape which upgrades it was assumed to need. That is the useful core of the old “place in line” metaphor. It becomes less accurate when projects are studied together and must prove readiness. FERC explains that Order No. 2023 moved the pro forma process toward first-ready, first-served clusters instead of one-by-one serial studies.

In a cluster, the relevant questions are which study cycle accepted the request, whether site control and deposits were satisfied, and whether the project survives later milestones. A queue identifier still helps you find its record, but it does not by itself produce a commercial-operation date. FERC’s rule fact sheet names deposits, site control, study deadlines, affected-system reviews, and withdrawal penalties. These make a speculative early filing less valuable than a project ready to proceed.

Suppose Project A entered an old serial queue before Project B but lacked land rights. Under a readiness-based cycle, A cannot simply hold priority forever without meeting the operator’s conditions. Conversely, B’s completed application does not remove the need for a line upgrade. The right way to assess either project is to inspect its cycle, milestone status, study results, and pending construction scope. That is the queue-position material formerly presented on its own page; it belongs with the process it describes.

The rule targets generator interconnection. It requires transmission providers to conduct cluster studies, publish available-capacity information, strengthen site-control and financial-readiness requirements, allocate certain costs across a cluster, and address delays and affected-system studies. FERC’s fact sheet summarizes those elements. It also allows multiple generating facilities on one shared site to use a single point of interconnection under specified conditions.

For a concrete example, a solar project and a storage project proposed at the same point may share a request rather than each assuming a separate connection. Their combined operating model still matters; storage that charges at peak demand creates a different network case from storage that charges during solar surplus. The reform addresses how a provider studies and allocates such impacts, not whether the project has building permits or a supplier contract.

The 2024 Order No. 2023-A explanation clarified parts of the cluster request window and withdrawal treatment. Regions also have transition filings and local variations, so do not assume every live queue has exactly the same sequence. PJM, for example, described its new cycles and reported active study work in June 2026. That operator update also separated study processing from later permits and supply-chain work.

At the end of 2025, Berkeley Lab’s 2026 edition counted about 8,200 active projects representing 1,312 GW of proposed generation plus roughly 749 GW of storage in U.S. transmission queues. That is requested capacity, not capacity under construction or a forecast of what will be built. The lab found that only 13% of capacity requesting interconnection from 2000 through 2020 had reached commercial operation by the end of 2025; many requests had withdrawn.

For projects built in 2025 in regions with duration data, the median request-to-commercial-operation interval was more than five years. This interval includes much more than a waiting-room pause: studies, agreement, project development, upgrades, and construction can all lie between filing and operation. It describes completed generator projects, not every current project’s remaining wait. It certainly does not measure the average load-service timeline for a new AI facility.

A developer can use the national numbers to understand congestion in the generation pipeline, then narrow to the relevant operator and substation. MISO offers an interactive generator queue and downloadable data; CAISO publishes cluster-study materials. These are better inputs to a local screening discussion than the national headline. Even then, a public queue cannot replace the provider’s formal study of a proposed connection.

A data center drawing power is a load, not a generating facility. It may need a utility service request, a large-load study, transmission service, local distribution upgrades, or a co-located generation arrangement depending on location and design. The Berkeley Lab queue report expressly excludes load requests. Do not put a campus into the generator queue merely by translating its facility megawatts into a request number.

As of November 2026, the federal large-load framework remains in motion. DOE’s October 2025 direction opened the policy push reflected in FERC docket RM26-4. FERC issued six June 2026 show-cause orders asking regional operators to justify or reform the tariffs used for large loads. Those orders are preliminary actions, not a final nationwide large-load rule.

A regional example shows why the distinction matters. Southwest Power Pool’s HILL process was approved in January 2026 for high-impact loads paired with existing or planned generation. That is a load-focused framework with its own study design, not the generic generator cluster from Order No. 2023. A campus should ask the serving utility and transmission provider which exact path applies to its proposed import, export, and co-location modes.

Start at the grid operator’s own queue or planning portal. Look for the request identifier, study cycle, point of interconnection, requested capacity, fuel or storage type, study phase, and agreement status. MISO’s generator-interconnection page links its active-project map, interactive queue, and process metrics. CAISO posts study timelines and cluster materials. PJM’s Planning Center describes the applications supported by its NextGen and QueuePoint tools.

For a hypothetical 150 MW solar project, do not read “active” as “approved.” Check whether the operator has completed the study, whether the developer accepted upgrade obligations, and whether the agreement is executed. A project can have an agreement and still be waiting on permits, equipment, or construction. Berkeley Lab’s report counted capacity with draft or executed agreements that was not yet operating; it did not label that capacity as ready for immediate delivery.

For a data-center load, ask for the applicable utility or RTO large-load process and written service status. The public generator map may show nearby power plants but omit the campus request. If a proposed on-site plant will also export, track its generator connection separately from the campus’s load service. This gives the project schedule two explicit paths instead of hiding one behind the word “interconnection.”

Do not equate an assigned queue number with a reserved completion date. Study cycles, readiness milestones, upgrades, and later construction control when power can flow. Do not add generation and storage gigawatts as though they were all independent firm plants: a hybrid project can include both and many requests never reach operation.

Most of all, do not use a generator-queue median to promise a data-center connection date. A load request follows the rules of its service territory. Finally, a behind-the-meter design does not settle the question if the project also wants grid backup or exports. Write each requested operating mode down and ask the provider how it will be studied.