Air-permit underwriting · turbine siting
Siting tools tell you where the land is. This tells you what the turbines themselves will get out of a site once the air permit hits. Enter your fleet below to drive the county heatmap live; scroll for the state-level view and comparable issued permits.
County heatmap · your fleet
Color is air-permitting difficulty: minor-source vs Title V + BACT vs NNSR + LAER + offsets. Overlay is 2015 ozone NAAQS attainment from EPA Green Book; county opacity reflects RBLC BACT precedent density for stationary combustion turbines. Hover for the binding constraint; click for the permit pathway.
Fleet preset
Site potential to emit
Site MW
88 MW
Uncapped NOx @ 8,760 hr
23 tpy
Enforceable NOx @ 4,000 hr
10.6 tpy
Enforceable CO @ 4,000 hr
10.6 tpy
Enforceable PTE below 100 tpy Title V trigger — synthetic-minor permit posture, assuming the dispatch-hour cap is federally enforceable.
Minor source
State-only permit, 3–6 mo
3,130 counties · 100%
Title V · BACT
Attainment major, 9–15 mo
0 counties · 0%
NNSR · LAER + offsets
Marginal/moderate NAA, 12–18 mo
0 counties · 0%
NNSR · scarce offsets
Serious/severe/extreme NAA, 18–30 mo
12 counties · 0%
Fleet-wide siting readout
Of 3,142 US counties, this fleet lands in a state-only minor-source permit in 3,130, triggers full Title V + BACT in 0, lands in tractable NNSR + offsets in 0, and hits NNSR with scarce offsets in 12. Hover any county to see its binding constraint; click for the detail panel.
Directional model. Classification assumes a federally enforceable hour cap at the selected dispatch profile (synthetic-minor posture); uncapped PTE at 8,760 hr is shown separately. Emission factors from AP-42 Ch. 3.1 rule-of-thumb lb/MWh. Nonattainment classifications from EPA Green Book (2015 ozone NAAQS, 2012 PM2.5 NAAQS), full-county approximation. RBLC density is a state-level proxy from public BACT/LAER determination counts. Not a permit application. Real work requires unit-specific vendor data, site-specific dispersion modeling, and a live RBLC pull.
State cartogram · reference fleet
A zoom-out view for when you want to compare states at a glance. This cartogram runs one hardcoded reference fleet — the kind a typical BTM-bridge turbine seller is marketing in the US right now — against every state agency rule set. Green means fast synthetic minor; red means PSD or LAER in nonattainment.
3 to 9 months
9 to 18 months
18 to 30 months
Hover a tile for the state-specific rationale; click to open that state's air-permit authority. Demo classification; the production product runs per parcel.
Comparable permits
Five recent comparables pulled from public issued permits. The real deliverable surfaces the 3 to 5 most comparable permits for a specific site and turbine spec, with timeline to issuance, BACT determination, operating limits, and appeal history. Sources are EPA RBLC, EPA ECHO, and state agency public dockets.
xAI Colossus 1 (Memphis, TN)
Shelby County Health Dept — SCHD
247.2 MW
15 methane gas turbines
Enforceable limits keep aggregate under Title V thresholds (100 tpy criteria, 10 tpy single HAP, 25 tpy combined HAPs). Consultant of record: Trinity. 35 turbines observed on-site; EPA rejected the 'temporary/non-road' exemption theory after the June 2025 NOI-to-sue.
SCHD air permit notices→xAI Colossus 2 (Southaven, MS)
Mississippi DEQ — MDEQ
Est. 700+ MW
41 methane gas turbines
Appeal filed 2026-04-09 by SELC/NAACP. Permit terms are a moving target until the appeal resolves; do not underwrite Mississippi as definitionally fast on the basis of this single issuance.
MDEQ air division→Torrance Denker / Performance Team (CA)
SCAQMD
10 MW
Reciprocating engines, fuel-flexible
Prologis BTM case study. Proves that even in SCAQMD, recip + multi-fuel can get permitted if emissions engineering is right. Fuels: NG, propane, hydrogen. Useful counterexample to 'California impossible' framing; but 12-month path was extraordinary, not typical.
SCAQMD permit lookup→VoltaGrid Project Frontier (Shackelford County, TX)
TCEQ
2,000 MW (phased)
Multi-phase fleet
In-house 5 FTE air permit team at VoltaGrid files directly in Texas. In non-Texas deployments the hyperscaler customer files instead. Concrete design-partner target for the timeline-compression product.
TCEQ Air Permits→Generic 8 x 23 MW NG peaker — attainment county in VA
VA DEQ
184 MW
8 aeroderivative turbines
Plain-vanilla synthetic minor path if fleet accepts SCR + DLE + hour cap. Post-APG-578 (2025-09-30), utility outages noticed within 14 days may qualify as emergency. Critical variable for BTM underwriting.
VA DEQ data center permits→Method
County-level attainment status for ozone, PM2.5, PM10, NO2, SO2, CO, and Pb. Sets whether the site is in attainment, marginal, moderate, serious, severe, or extreme nonattainment, which in turn drives PSD vs. LAER vs. offset-required posture.
Every BACT determination on file for stationary combustion turbines. Surfaces the realistic NOx, CO, VOC, PM, and HAP limits you will be held to in each region, with cost-per-ton trajectories over time.
TCEQ, VA DEQ, GA EPD, Ohio EPA, IEPA, CARB + local air districts, MDEQ, and dozens more (every jurisdiction tile on the map above links straight to its air-permit authority). Issued permits, statements of basis, public-comment dockets, and appeal histories, each scoped to the specific turbine technology class.
Aggregate potential-to-emit across all fleet units, tested against the 100 tpy criteria / 10 tpy single HAP / 25 tpy combined HAP thresholds. Determines whether the fast synthetic minor path is viable at the proposed dispatch.
40 CFR 60 Subpart KKKK (NSPS for new gas turbines), 40 CFR 63 Subpart YYYY (turbine MACT), and 40 CFR 63 Subpart ZZZZ (RICE NESHAP for any recip backup). These are the same in every state and set the non-negotiable baseline.
Explore the five live state pages: /permitting
Run your fleet
Make, model, MW per unit, count, fuel, and intended dispatch profile. We return a county-level air-permit readout with the 3 to 5 most comparable issued permits per candidate site.