The Queue Report

Industry coverage this spring cited "more than 3,000 projects" pending at Ameren Illinois. As of the June 9 snapshot, the public queue holds 3,334 projects totaling 13.74 GW of proposed DER capacity. Of those, 2,335 projects (10.2 GW) remain active and pre-construction — 1,886 in Pending Review alone (8.7 GW). Only 998 projects have reached construction or beyond.

For scale: 10.2 GW of waiting distributed capacity is roughly three times ComEd's entire installed DER base and nearly equal to the entire U.S. community solar fleet built to date (10.1 GW, per Wood Mackenzie). It is concentrated on one downstate utility.

The queue operates serially: each project's review can wait on the project ahead of it. The public data exposes this as a literal "Waiting On Project" field — which means the blast radius of every dispute is computable. Nobody appears to have computed it.

The 134 projects currently In Dispute hold just 556 MW. But walk the dependency chains downstream and the picture changes: 109 projects (510 MW) are waiting directly on a disputed project, and 1,138 active projects — 5,232 MW — sit somewhere behind a dispute in their chain. That is 51% of all active capacity in the queue, gated by the slowest-moving 4% of it.

Disputes touch 41 of the 71 active queue areas. The mid-March figure reported in trade press was 123 disputes; the count is now 134 and rising.

Chain depth — how many projects must clear before yours reaches the front — is the single most decision-relevant number in the dataset, and it appears nowhere on any status page. Computed across all active projects: median chain depth is 14; the mean is 28; the deepest chain runs 219 projects long (DER-79370, in the ER-series corridor).

Under Ameren's current serial-study regime (concurrent studies are not promised until January 2027), chain depth converts roughly into review cycles. A project at depth 14 with even an optimistic 2–4 weeks per upstream resolution is looking at 6–13 months of structural wait before its own review completes — before any construction timeline begins.

Ameren reports its queue in 71 area queues. The top ten by active capacity hold 5.7 GW — 55% of everything waiting. Queue area ER-4 alone holds 324 active projects (1.44 GW) and 14 live disputes; NRP-1 follows with 1.02 GW. Siting decisions made today without this map are siting decisions made blind.

WRN-8 and SRN-11 are the quiet stories: mid-size queues carrying outsized dispute density (14 and 8 live disputes respectively). Projects entering these areas inherit the highest blockage probability per MW in the territory.

Under the OBBBA, solar projects that didn't start construction by July 4, 2026 (24 days from publication) must be placed in service by December 31, 2027 to keep the federal ITC. In the Ameren queue today, 2,113 projects of 1 MW or larger — 9.9 GW — have not yet cleared review.

At a conservative $1.4M/MW capex and a 30% credit, the queue is holding roughly $4.2 billion of ITC value hostage to interconnection timing. For a single standard 5 MW community solar project, the stake is ~$2.1M — against a median chain depth of 14 and a 51% chance of standing behind a dispute. The 1,520 active projects in the 4.5–5 MW class (7.6 GW) are almost all Illinois Shines community solar economics, where losing the ITC doesn't trim returns; it kills the project.

ComEd's latest ICC grid-plan filing shows its capacity sitting where its queue isn't: the Chicago region holds 947 MW of available hosting capacity but just 61 MW of queued DER (2%), while the South and West regions carry 1,157 MW and 1,222 MW of queued capacity against only 518 MW and 347 MW of hosting headroom. Illinois's two big utilities are mirror images: Ameren's problem is process throughput; ComEd's is geographic mismatch. Developers playing both territories are navigating two different games with one set of public maps — updated on a lag the utility itself acknowledges.