120 coal plants, 25 months, one playbook.

Every retired coal plant carries three latent assets that take years to build from scratch: transmission interconnection capacity, heavy-industrial zoning, and cooling water access. For a data center developer, these are the three slowest steps of predevelopment. The average new build waits 5 to 9 years to reach commercial operation in most US ISOs; a coal conversion can compress that timeline to 2 to 3 years by inheriting infrastructure that's already in place.

The economics reflect this. A greenfield data center with new interconnection typically costs $150–400 per MW capacity for grid upgrades alone, not counting years of ISO study and study deposits. A coal conversion that reuses existing POI capacity typically spends a fraction of that on upgrades and skips the multi-year cluster study altogether.

The strategic premium is acceleration. Every 12 months of acceleration is roughly $14.2 million per month of opportunity cost per 60 MW of GPU capacity, per our industry model. For a 500 MW campus, accelerating by 24 months represents over $1 billion in opportunity cost recaptured. A coal conversion that compresses the timeline by even 12 months is worth hundreds of millions in enterprise value.

Homer City, Pennsylvania — 1,884 MW of retired coal, Indiana County — became the template after Homer City Redevelopment announced a $10 billion conversion to a gas-fired generation and data center campus in 2025. The conversion combines natural gas turbines on-site with a purpose-built data center, sharing the existing 500 kV interconnection into PJM.

What makes Homer City the template is the combination of factors that had to align: (1) a fully retired coal plant with existing 500 kV interconnection, (2) a motivated sponsor with capital, (3) a local community amenable to continued industrial use, (4) a state regulatory framework that could accommodate the restructure, and (5) a clear path through the PJM queue. Each of these alignments is rare; having all five is rarer still.

The Homer City team took about 25 months from initial evaluation to public announcement. Most of that time was spent on the regulatory work — ISO coordination, FERC filings, PA PUC engagement, community agreements, environmental review. The actual construction timeline is shorter than the regulatory timeline. This is the pattern most coal conversions follow.

Our Site Intelligence index scores every retiring coal plant on seven factors: POI voltage, transmission headroom, retirement schedule, remediation status, zoning classification, water availability, and sponsor readiness. The blend produces a 0–100 fit score that reflects BTM viability.

The top 20 sites by fit score include Homer City (PA, 94), Morgantown (MD, 88), Bowen (GA, 86), Roxboro (NC, 85), Amos (WV, 79), Kingston (TN, 82), Keystone (PA, 81), and several mid-Atlantic and Appalachian candidates where PJM queue access is best and water availability is strong.

The bottom end of the list — not because they're bad sites but because conversion is less straightforward — includes plants with longer retirement horizons (Gibson IN, Labadie MO), plants in regions with softer DC demand (Craig CO), and plants with significant remediation exposure (several legacy plants we flag but don't publish for diligence reasons).

The scoring is the starting point, not the answer. Every top-scoring site still requires physical diligence, sponsor negotiation, and a realistic regulatory pathway analysis before it becomes a live opportunity. Our role is to compress the filter step from months of consultant work to a few hours in our index.

A coal conversion triggers a specific sequence of regulatory filings. First, the retiring plant owner files a generator retirement with the ISO. This opens a window in which the interconnection capacity becomes eligible for reuse — but only for a limited period and only under specific rules.

Second, the new sponsor files an interconnection request under the reuse framework. This is where ISO-specific variation kicks in. PJM has a relatively streamlined reuse process under its queue reform. MISO's DPP Phase III supports coal conversion cases with explicit provisions. ERCOT handles reuse through its existing cluster framework. CAISO's reuse framework is the slowest and least developed.

Third, the conversion triggers state-level regulatory work. Environmental review of the site transition. State PUC engagement on any rate structure changes. Local zoning confirmation. Community benefit negotiation. And where nuclear or gas on-site generation is involved, NRC or FERC filings on the generation asset itself.

Fourth, the financial and commercial structure is locked in. This is where the deal looks like a BTM Workflow deal — our regulatory graph tracks the commercial filings alongside the conversion-specific environmental and interconnection filings so the same workspace handles both sides.

Each of these four steps takes months. Running them in parallel saves months to years. Running them sequentially guarantees a multi-year timeline. Our Predevelopment Services team coordinates the parallel execution; BTM Workflow tracks the filings; Site Intelligence identifies the candidate in the first place.

The first wave of coal conversions — Homer City, Babcock & Wilcox / Denham, Xcel — was won by teams with very specific advantages: capital, relationships with the retiring operator, and existing DC domain expertise. The next wave (roughly 2027–2029) will see a different shape of winner.

The next wave winners will have three characteristics. First, they will move faster on diligence than the first wave. The first wave took 18–24 months of diligence per site because the playbook didn't exist; the next wave compresses diligence to 4–8 weeks because the playbook is public. Second, they will have better financing structure — the first wave was largely equity-heavy; the next wave uses tax-exempt bonds, DOE loans under §1706, and structured commercial financing. Third, they will execute the four-step regulatory pathway in parallel rather than sequentially, saving months to years.

Our Site Intelligence product is designed to help the next wave move. Predevelopment Services is designed to compress the diligence timeline. BTM Workflow is designed to handle the deal structure. The next wave of coal conversions will buy this stack — and probably rebuild the whole industry in the process.