TVA's New Cluster-Based Interconnection Queue: A Technical Walkthrough LGIP

If you're a developer, EPC firm, or asset owner planning to connect a generating facility larger than 20 MW anywhere in the Tennessee Valley Authority's footprint, the rules changed. TVA's revised Standard Large Generator Interconnection Procedures (LGIP) — posted October 1, 2024, replace the old serial, first-come-first-served queue with a cluster study process. This is TVA's implementation of the reforms FERC set out in Order No. 2023, and it touches almost every commercial and engineering decision you'll make about a project's timeline, deposits, and exposure to cost risk.



This post walks through the mechanics that actually matter when you're scoping a project: how the annual window works, what it costs to get in the door, how studies are sequenced, how network upgrade costs get allocated across a cluster, and — critically — what it costs to get out if your project doesn't pencil.

From serial to cluster: why the model changed

Under a serial queue, each interconnection request is studied in order, one behind the next, with each project's upgrade costs evaluated against everything ahead of it. The well-documented failure mode is the cascade: a higher-queued project withdraws, every downstream study has to be reworked, and the whole line stalls. Speculative requests with no real site control or financing clog the queue and inflate study timelines for serious projects.



The cluster model attacks this directly. Instead of a continuous queue, TVA now opens a defined annual window, gathers all the requests that arrive during it, and studies them together as one group against a common base case. Every project validated in a single window is treated as equally queued — there is no jockeying for an earlier timestamp within a cluster. Projects in an earlier annual cluster hold a higher queue position than those in a later one, but inside a given cluster, position is flat.

The trade-off is structural: you give up the ability to jump the line by filing early, and in exchange you get a study process designed to be more predictable, with cost-sharing across the group and financial commitments that screen out projects that aren't real.

The annual window and what "equally queued" means in practice

TVA accepts interconnection requests during a 45-calendar-day Cluster Request Window. After the initial transition window, successive windows open every January 15. Requests submitted outside the window are not considered — there's no rolling intake anymore. If you miss January, you wait a year.

Because every validated request in the window shares the same queue position, the competitive dynamic shifts away from speed and toward readiness. The differentiators become:

do you have site control, do you have a credible point of interconnection, and can you post the required security. That's a deliberate design choice — the queue is no longer a land grab on timestamps.

What it costs to enter: deposits and the commercial-readiness screen

This is where the new rules bite first. To submit a valid request you need to assemble a fairly substantial package up front:

A non-refundable application fee of $25,000, plus a refundable study deposit scaled to project size:

• $150,000 for requests under 75 MW
• $200,000 for requests from 75 MW up to (but not including) 200 MW
• $300,000 for requests of 200 MW or more

On top of the study deposit, you must post a Commercial Readiness Deposit equal to twice the study deposit — so a 250 MW project is looking at a $300,000 study deposit plus a $600,000 commercial readiness deposit, in cash or another security form TVA accepts. This deposit is the financial backbone of the new withdrawal-penalty regime (more on that below), and it's refundable per the withdrawal rules.

You also need to demonstrate 100% site control at submission — the exclusive land right to develop, construct, operate, and maintain the facility over its expected operating life. There's a narrow carve-out: if site control is genuinely unobtainable because of a defined regulatory limitation, you can substitute a deposit in lieu of site control of $10,000/MW, subject to a $500,000 floor and a $2,000,000 ceiling — but you still have to show you're actively pursuing the approvals, and you must reach full site control within 180 calendar days of the LGIA's effective date.

The design intent here is unambiguous: raise the cost of speculative entry so that the cluster is populated by projects with real land, real money, and real intent. If you've been treating an interconnection request as a cheap option on a site, that approach no longer works in TVA territory.

The full sequence, window to agreement

The Cluster Study Process runs as a defined sequence with hard timeframes attached to most steps. Here's the path a request travels:

1. Cluster Request Window (45 days).

Submit the complete package. TVA acknowledges receipt within 5 business days. If your request is deficient, TVA notifies you within 5 business days, and you have 10 business days to cure — but never past the close of the window.

2. Customer Engagement Window (60 days).

Opens when the request window closes. TVA holds a Scoping Meeting with all interested customers, posts an anonymized list of the cluster's requests to OASIS (capacity, county/state, interconnecting station or line, projected in-service date, service type, and fuel/facility type — no identities), and provides a non-binding cost-and-timeframe estimate plus a Cluster Study Agreement. You must execute that agreement before the window closes, or your request is deemed withdrawn, your application fee is forfeit, and your deposits are returned.

3. Cluster Study (150 days).

TVA evaluates the whole cluster together with power flow, stability, and short-circuit analyses against the base case, plus higher-queued pending requests and executed-LGIA projects. The single Cluster Study Report identifies the required interconnection facilities and network upgrades, non-binding cost estimates, and — importantly — each customer's estimated allocated share of those costs. Notably, the study must also evaluate a defined set of alternative transmission technologies (static VAR compensators, advanced power flow control, synchronous condensers, voltage source converters, advanced conductors, tower lifting, transmission switching, and more) and explain the results for each in the report. A Cluster Study Report Meeting follows within 10 business days.

4. Restudy gate.

Within 20 days of the report meeting, you must demonstrate continued site control and top up your Commercial Readiness Deposit to 5% of your allocated network upgrade cost (rounded up to the nearest $10,000). If anyone withdraws, TVA decides within 30 days whether a Cluster Restudy is needed; restudies run on the same 150-day clock and follow the same scope.

5. Interconnection Facilities Study (180 days).

Once no further restudy is required, this study is done individually, not clustered — it's the detailed engineering of the switching configuration, transformer, switchgear, metering, and the construction cost and schedule to physically connect you. Executing the agreement requires topping the Commercial Readiness Deposit up to 10% of your allocated network upgrade cost. You get a draft report, 30 days to comment, and a final report 15 business days after comments.

6. LGIA.

TVA tenders the Standard Large Generator Interconnection Agreement, and you proceed toward construction and commercial operation.

Add it up and you're looking at a multi-year path even when everything runs on schedule, which is why the deposit and milestone structure is built to weed out projects before they consume study resources.

How network upgrade costs get allocated

This is the part that determines whether a project is viable, and the methodology is specific.

Substation Network Upgrades

(including switching stations) are allocated per capita — first across the interconnection facilities connecting to the substation at the same voltage level, then per capita across each generating facility sharing the interconnection facility. Per capita means per generating facility, not pro-rata by megawatts.

System Network Upgrades

 (anything required beyond the point-of-interconnection substation) are allocated by proportional impact — each facility's share is based on how much it contributes to the need for that specific upgrade. TVA posts the detailed methodology on OASIS, broken out by category: system protection, lines and transformers, voltage support, short-circuit upgrades, stability upgrades, system strength upgrades, and so on.



Interconnection Facilities

 (the direct connection equipment) are directly assigned to the customers using them, shared per capita where customers agree to share.

Customers who fund network upgrades are entitled to transmission credits under the LGIA. The key engineering takeaway: because system upgrade costs follow proportional impact, the marginal cost of your project depends heavily on what else is in your cluster and where it connects. Two identical facilities can carry very different cost allocations depending on cluster composition.

Early in the process a developer must choose the type of interconnection service. This single choice shapes how the project is studied, what upgrades it triggers, and what it is allowed to do in the capacity market.

The withdrawal penalty: the sharpest edge in the new rules

Here's the mechanism that changes the risk calculus most. Under the cluster model, when a project leaves, it can force restudies and shift costs onto everyone who stayed. The withdrawal penalty exists to internalize that cost.

You are not penalized if you withdraw before the initial Cluster Study commences. After that, the penalty escalates with how far you've progressed:

• During the Cluster Study or after the Cluster Study Report (before restudy or facilities study): the greater of 2× your study deposit, or 2× your study deposit. (At this stage the floor is 2× the study deposit.)

• During the Cluster Restudy (before the facilities study): the greater of 2× study deposit or 5% of estimated allocated network upgrade costs.

• During the Interconnection Facilities Study, or after its report but before executing the LGIA (with milestones met): the greater of 2× study deposit or 10% of estimated allocated network upgrade costs.

• After executing the LGIA, or if the facility otherwise never reaches commercial operation: 20% of estimated allocated network upgrade costs.

There are important exemptions that protect you from runaway cost estimates: no penalty if you withdraw before LGIA execution and your exit doesn't materially affect cost or timing for others in the cluster; no penalty if your network upgrade costs jumped more than 25% in your latest Cluster Restudy Report versus the prior report; and no penalty if costs rose more than 100% in your Interconnection Facilities Study Report versus the Cluster Study or Restudy figure. In other words, if TVA's own restudies blow up your number beyond those thresholds, you can walk without paying the penalty.



Penalty funds don't just disappear into TVA. For a given cluster, TVA holds all penalty funds until every project has either withdrawn or executed an LGIA, then applies them first to fund studies for the customers who stayed and executed LGIAs, and next to offset the net cost increases those remaining customers absorbed because a co-funding project left. The balance held is posted quarterly on OASIS. It's a genuine risk-sharing pool, not a fine.

What this means for your project planning

A few practical implications worth internalizing:

Treat the January window as a hard annual deadline.

There's no rolling queue to slip into. Missing the window costs you a full year.

Front-load your readiness.

Site control and the deposit stack are now gating items, not paperwork you tidy up later. Budget the application fee, study deposit, and 2× commercial readiness deposit as a cost of entry.

Model your withdrawal exposure as a real line item.

Once the cluster study starts, exiting costs money — and the further you go, the more it costs. But also model the exemption thresholds: the 25% and 100% cost-increase off-ramps are your protection against committing to a project whose economics the studies have quietly destroyed.

Your costs are coupled to your neighbors.

Proportional-impact allocation for system upgrades and per-capita allocation for substation upgrades mean your number moves with cluster composition. Watch the anonymized OASIS posting to understand what you're clustered with.

Storage and partial-service requests have real flexibility.

TVA will study storage-inclusive facilities using your proposed charging assumptions (e.g., not charging at peak), and will study interconnection service below full facility capacity using injection-limiting equipment — both of which can reduce required upgrades, subject to good utility practice and reliability standards.

The cluster model trades the old queue's illusion of speed for a more disciplined, more predictable, and more capital-intensive process. For serious projects with site control and financing, that's mostly good news. For everyone else, the new deposits and penalties are exactly the filter they were designed to be.

FAQ: TVA's  Cluster-Based LGIP