U.S. Senator Raphael Warnock and U.S. Representative Hank Johnson, both of Georgia, are calling on the Environmental Protection Agency to immediately regulate emissions from the diesel generators that power and backstop the state’s booming data-center industry. The two Democrats sent a letter dated October 22 accusing the agency of failing to oversee a technology now multiplying by the hundreds across Georgia’s computing campuses.
According to The Atlanta Journal-Constitution, the lawmakers’ letter warns that diesel generators at Georgia data-center sites number in the hundreds and that, combined, their emissions would release more than twice the nitric oxide of two of Georgia Power’s large coal-fired plants, per the letter. Warnock and Johnson argue the generators pose potential harm to the health and safety of surrounding communities.
Data centers are driving a surge in electricity demand across the state, and diesel generators are used both for backup power during outages and, increasingly, for periods of peak demand when the grid can’t keep up. QTS is one of the companies building that infrastructure, with its Project Excalibur campus in Fayetteville. Georgia Public Broadcasting reported that the QTS Fayetteville project had 205 diesel generators approved in 2023, a single campus illustrating how quickly the hardware has scaled up statewide.
A Permitting Surge Few Saw Coming
The pace of approvals backs up the senators’ alarm. Georgia has approved 20 minor-source permits for diesel generators at data centers since January 2025 alone, GPB’s reporting shows, compared with just 17 issued during the entire decade from 2014 to 2024. Altogether, the station notes that all approved minor-source permits in the state are set to house more than 2,600 diesel generators.
The scale of that backup capacity is striking on its own. The Sierra Club found that 24 Georgia data centers alone provide 5.2 gigawatts of backup power. The group also estimated that if 212 data centers were each allowed a 99-ton annual nitrogen oxide limit, their combined emissions could reach roughly 21,000 tons a year.
Large campuses can propose dozens or hundreds of generators at once, and when their combined emissions cross certain thresholds, it can trigger the need for a state air permit, as Axios Atlanta has reported.
Federal Rule Change Looms Over the Fight
The senators’ letter operates within the Clean Air Act’s framework for minor-source permits, which until now has required at least minimal public participation before approval. That framework is itself in flux: the EPA proposed on July 2 to streamline the New Source Review permitting process for minor sources by eliminating minimum federal regulatory requirements for public participation, the agency said in its own announcement. Critics worry that change would make it even harder for residents near sites like Project Excalibur to weigh in before hundreds more generators get approved.
Georgia’s surge isn’t happening in isolation. The Atlanta Journal-Constitution has reported that Georgia leads the nation in data-center development. Some projects are waiting to connect to the grid. Generators can provide emergency backup and, in some cases, a stopgap power source while they wait.
How Virginia Is Handling the Same Problem
Other states further along in the data-center buildout have already moved to tighten the rules. Virginia has roughly 9,000 diesel generators statewide, with about 4,700 concentrated in Loudoun County alone, according to VPM. In response, Virginia’s State Air Pollution Control Board adopted a new rule on August 18 establishing specific emissions standards for data-center generator sets, according to Alliance Technical Group.
Under Virginia’s new standard, every generator at a covered data center must meet emissions limits equal to or better than a Tier 4 equivalent engine, the cleanest tier currently defined for such equipment. The rule applies to air-permit applications submitted on or after July 1, including requests for coverage under a general permit, offering an example of a state-level approach to data-center generator rules.
Warnock and Johnson have urged the EPA to address their concerns. Federal regulators could move toward a Georgia-specific standard, defer to the state’s existing air-quality rules, or press ahead with the proposed rollback of public-participation requirements. The letter says that even if the diesel generators operate within existing state emissions standards, their combined emissions would more than double those of the two coal plants, even as Georgia continues to approve minor-source permits for data-center generators.
