On December 11, 2025, the EPA’s Office of Air and Radiation launched a new resource page consolidating Clean Air Act guidance for data center developers. The resource is part of the Trump administration’s broader effort to accelerate energy infrastructure development and reflects the growing recognition that air permitting has become a critical bottleneck for AI and data center projects.
What’s in the New Resource
The EPA’s data center resource page brings together guidance, regulations, and technical tools that were previously scattered across multiple agency webpages. Key resources include:
Permitting Guidance: Potential to emit (PTE) calculations for emergency generators, including methods for limiting PTE to avoid major source classification
- Guidance on aggregation and “adjacency” interpretations for determining stationary source scope
- “Begin Actual Construction” interpretations relevant to project timing
Applicable Standards: New Source Performance Standards (NSPS) for stationary combustion turbines and reciprocating internal combustion engines commonly used for primary and backup power
- National Emission Standards for Hazardous Air Pollutants (NESHAP) for these same source categories
- Title V operating permit requirements for major sources
Technical Tools: Air quality dispersion modeling guidance and preferred models under 40 CFR Part 51, Appendix W
- Air quality analysis checklists
- Particulate matter testing guidance
Why This Matters: NSR Reform and the Permitting Bottleneck
The new data center resource page arrives alongside a series of EPA actions aimed at reforming New Source Review (NSR)—the preconstruction permitting program that has become a significant bottleneck for power generation and industrial projects.
“Begin Actual Construction” Redefined
On September 2, 2025, EPA issued guidance redefining what it means to “begin actual construction” under NSR. The new interpretation allows developers to proceed with “core and shell” construction—including foundations, structural steel, and external walls—before receiving their NSR permit. The key limitation that remains is that no emissions units, foundations for emissions units, or related piping can be installed until the air permit is issued.
For data center projects with lengthy permit timelines, this change is significant. Developers can now begin site work and building construction while the air permit is under review, potentially shaving months off project schedules. EPA has indicated it plans to codify this interpretation through rulemaking, with a proposed rule expected by January 2026 and a final rule by September 2026.
Reactivation Policy Rescinded
On September 18, 2025, EPA rescinded its long-standing policy treating facility restarts as triggering NSR review. Under the new approach, restarting an idle facility only triggers NSR if the restart involves a “major modification”—a physical or operational change that increases emissions above applicable thresholds. This provides significant flexibility for bringing mothballed power plants or industrial facilities back online without a full NSR permitting process.
Aggregation and Adjacency Guidance
The new resource page also consolidates existing guidance on source aggregation—a critical issue for data center developers pursuing on-site power generation. Under NSR, pollutant-emitting activities are aggregated into a single “stationary source” if they share the same SIC code, are under common control, and are located on contiguous or adjacent properties. Whether a data center and its co-located power plant are treated as one source can determine whether combined emissions trigger major NSR/PSD thresholds.
EPA’s 2019 adjacency guidance—which remains in effect—clarified that “adjacent” should be interpreted based on physical proximity alone, not on whether facilities are functionally interrelated. For projects where aggregation could push emissions over major source thresholds, careful attention to facility siting, ownership structures, and potential-to-emit limitation strategies can make the difference between a minor source permit and a multi-year major NSR process.
Policy Context
EPA’s data center resource page is part of a coordinated Trump administration policy to accelerate energy infrastructure development. On his first day in office, President Trump signed “Unleashing American Energy,” which directs agencies to “eliminate all delays” in permitting processes and prioritize “efficiency and certainty” in environmental reviews. The order specifically calls for streamlining NEPA implementation and eliminating the social cost of carbon from permitting decisions.
The President also declared a national energy emergency, citing the need for reliable energy supplies “to power the next generation of technology.” The emergency declaration authorizes agencies to invoke emergency permitting authorities, including expedited Army Corps of Engineers permits and streamlined Endangered Species Act consultations.
Administrator Lee Zeldin framed the new data center resource in these terms: “The global race to harness the power of artificial intelligence and build data centers is underway…we need to win that race.”
What’s Next
EPA has signaled that the data center resource page is just the beginning. The agency is expected to continue developing guidance and potentially propose regulatory changes to further streamline air permitting for data center and power generation projects. Given the administration’s deregulatory posture—including an executive order requiring agencies to identify ten regulations for repeal for each new regulation issued—additional reforms to NSR and related programs are likely forthcoming.
Data center developers, independent power producers, and investors should take advantage of EPA’s new consolidated resource. Early coordination with EPA and state permitting authorities can help identify potential aggregation issues, develop PTE limitation strategies, and position projects for the most efficient permitting pathway.
