Data centers in Ashburn, Virginia (Gerville/Getty Images)
The Virginia Department of Environmental Quality published a new webpage listing data centers’ air permits, the approvals needed for the facilities to run diesel generators as a source of backup power in the event of any power grid outages, statewide.
“Since DEQ’s permits are not filed by industry type (i.e., factory or data center), it is very time consuming to locate and pull permits for each data center when they are requested,” said Irina Calos, a spokeswoman for DEQ. “Furthermore, these permits are too large to send through email, necessitating the use of a large file transfer program to send. By placing these permits on our website, we are able to ameliorate these hurdles.”
The webpage comes after other transparency initiatives have been introduced under DEQ Director Mike Rolband, including the creation of the Permit Enhancement and Evaluation Platform, or PEEP, a precursor of the Virginia Permitting Transparency platform.
DEQ has come under increasing scrutiny as data centers, the warehouses storing computers that process internet activity, proliferate in Virginia and present unprecedented energy and water demands.
Emissions from diesel generators have become a big part of the discussion on data center development, with DEQ last year considering a variance to reduce pollution requirements on the generators in light of electricity transmission delays. The request was withdrawn, with a solution identified between the industry and the regional grid operator.
This past legislative session, Sen. Suhas Subramanyam, D-Loudoun, and Del. Rip Sullivan, D-Fairfax, introduced bills that would’ve banned the use of diesel for onsite power generation in order to receive the tax credits the state is deploying to lure in more data centers. Both measures failed.
Concerns over diesel generators stem from the tiny particulate matter in their emissions. The American Medical Association found that long-term exposure to PM 2.5 was linked with increased risk of heart issues in California.
Noise from data centers is also part of the discussion. Sen. Danica Roem, D-Prince William, introduced a bill intended to control how loud facilities are and prevent generators from running 9 a.m. to 5 p.m. Monday through Friday.
In September, Fairfax County passed an ordinance to limit the noise from data centers, including requiring that “back-up generators must be 300 feet from the lot line of residential property or separated from the lot line of a residential district or residential property by the data center building.”
The DEQ webpage lists 177 air permits as of Nov. 12.
An analysis by the Virginia Mercury found that 155 are in the northern region of the state, with 16 in the Piedmont, and two each in the Valley, Southwest and Tidewater regions. Loudoun County has 85 permits, with Fairfax County having 34 and Prince William County having 26.
Amazon facilities make up 42 of the permits, and Microsoft has 14.
The oldest air permit dates back to Nov. 22, 2000 for the “RREEF America REIT II Corp. VVV,” data center in Fairfax County. The air permit for the Hayden Data Center in Loudoun County lists over 150 diesel generators.
Permits are not issued if a facility would cause emission exceedances above state and federal air quality limits, Calos said, and require onsite inspections to view records. A majority of the permits issued are Minor New Source Review, or mNSR ones, instead of Standard Operating Permits, or SOPs, which are for smaller facilities.
“As data centers have increased in size, mNSR permits have been issued more frequently, as they allow for new controls and emissions limits,” said Calos.
The Piedmont Environmental Council, a nonprofit focused on preserving the Piedmont region’s rural landscapes, has a map of air permits for data centers last updated in 2023. The group lauded the creation of DEQ’s website so, “reporters, academics, and other nonprofits no longer need to repeatedly request this information through Freedom of Information Act requests.”
“There are over 12 gigawatts worth of capacity in these permits with the vast majority consolidated in the relatively small and highly populated area of northern Virginia,” said Julie Bolthouse, director of land use at PEC. “What is the total amount of additional pollution if all were to operate on an emergency basis during an ozone alert period and what would be the public health impact? We deserve to know this basic information.”
Josh Levi, president of the Data Center Coalition that represents members of the industry, said diesel generators “typically operate infrequently and under limited conditions, including during manufacturer-specified testing and maintenance activities.” The generators are needed, Levi said, in order to ensure companies can provide “uninterrupted operations and provide essential connectivity and data flow to their customers.”
“Data centers are actively evaluating alternatives that can provide similar reliability, fuel availability, siting flexibility, and workplace safety protections,” Levi said. “As an interim measure, many data centers are looking to low-carbon fuel alternatives, including renewable diesel, where available.”