A solar project can have perfect land, a signed lease, and investor backing — and still sit idle for three to five years waiting for grid approval. The interconnection queue is the single most common reason solar projects are delayed or abandoned, and it's widely misunderstood by everyone except the developers living inside it.
What Is the Interconnection Queue
Before a solar farm can deliver power to the grid, the utility or grid operator has to study whether the local transmission system can handle it. That study process — and the line of projects waiting for it — is the interconnection queue.
Every new solar project that wants to connect to the grid submits an interconnection application to the relevant authority: a regulated utility, an independent system operator (ISO), or a regional transmission organization (RTO). The application gets assigned a position in the queue. Studies proceed roughly in order. A project can't skip the line.
The studies themselves are layered. Most jurisdictions run an initial feasibility study, then a system impact study, then a facilities study. Each one takes months. Each one can surface new upgrade requirements — equipment the developer must pay for before the connection is approved. If a project ahead of you in the queue withdraws (which happens constantly), it can change your study results, triggering restudies that add more months.
| Study phase | What it evaluates | Typical duration |
|---|---|---|
| Feasibility study | Whether the project can connect without obvious grid violations | 1–3 months |
| System impact study | Transmission constraints, required upgrades, cost allocation | 3–6 months |
| Facilities study | Final engineering and cost confirmation for required grid work | 3–6 months |
| Interconnection agreement | Contract execution; grid connection formally approved | 1–3 months |
In theory, a clean application runs 8 to 18 months. In practice, restudies triggered by queue withdrawals ahead of a project routinely double or triple that.
Why the Queue Is So Backed Up
The US interconnection queue held roughly 1,400 gigawatts of pending capacity by end of 2021, according to Lawrence Berkeley National Laboratory's annual Queued Up report — and reached approximately 2,300 gigawatts of active capacity by end of 2024, as projects that cleared studies or withdrew were removed and new applications continued to pile in. The grid was not designed for this volume of applications, and the study processes were built for a much slower pace of development.
Several factors compound the backlog:
Speculative applications: Developers routinely file multiple interconnection applications for projects they know won't all be built — hedging against study outcomes and site risks. This clogs the queue with projects that will eventually withdraw, but only after consuming study resources and affecting everyone else's timelines.
Transmission infrastructure age: Much of the US transmission grid was built decades ago and wasn't designed to absorb large volumes of distributed generation. Connecting new projects often requires expensive upgrades to substations, transformers, and transmission lines — costs that fall on the developer and frequently kill project economics.
Understaffed utilities: The engineers who run interconnection studies are a specialized and limited workforce. Most utilities and grid operators haven't scaled their interconnection teams proportionally with application volume. Processing times have lengthened even as FERC has pushed for reforms.
How Queue Position Affects Project Economics
Where a project sits in the queue affects more than just timing — it affects cost. Studies are done in clusters, with projects near each other in the queue often evaluated together. A project that joins a queue cluster after the feasibility study window closes may be pushed into the next study cycle, adding a year or more to its timeline.
Upgrade costs assigned during the facilities study can arrive late in the development process, after a developer has already spent significant money on permitting and land control. An unexpected $5 million substation upgrade requirement on a 20-megawatt project can make the entire deal unviable.
Projects that entered the queue in the 2018–2021 period in many MISO and PJM territories are only now receiving final interconnection agreements — five to seven years after application. CAISO and ERCOT have moved faster historically, but their queues have grown as well.
What FERC Order 2023 Changes
In 2023, the Federal Energy Regulatory Commission (FERC) issued Order 2023, the most significant reform to the interconnection process in two decades. The rule requires grid operators to shift from a serial, first-come-first-served study process to a cluster study approach — evaluating groups of projects simultaneously rather than one at a time.
The intent is to reduce total study time and eliminate the restudy cascade triggered by project withdrawals. It also introduces stricter readiness requirements — deposits and milestone deadlines — to reduce speculative queue clogging.
The rule is being implemented on a grid-operator-by-grid-operator basis through 2025 and 2026. Early results in the first cluster cycles have been mixed: fewer restudies, but upgrade cost allocations have in some cases increased as shared network upgrades are split among fewer queue participants than expected.
What This Means If You Own Land Being Evaluated for Solar
When a developer approaches you for a solar land option agreement, one of the first things they're doing during that option period is running interconnection studies. The option period — typically two to five years — exists largely to accommodate this process.
A developer who goes quiet after signing an option isn't necessarily abandoning the project. They may be waiting on a system impact study result, negotiating upgrade cost allocations, or navigating a restudy triggered by another project's withdrawal.
The risk for landowners is that a project can clear every local hurdle — zoning, environmental, community approval — and still fail because interconnection costs came in too high to support viable project economics. When that happens, the developer exits the option, you keep your option payments, and the land goes back to its prior use.
This is also why substation proximity matters so much in the initial offer. A parcel close to a high-capacity substation with available headroom faces a shorter, cheaper interconnection path — and a lower risk that the studies come back with deal-breaking upgrade requirements. That lower risk is priced into the offer from the start.
Sunnyplans shows substation and transformer proximity for individual parcels — the factor that most directly predicts interconnection cost before a developer runs formal studies.