Va. regulators propose easing emission limits for data centers over power transmission concerns

Roughly 150 data centers in Fairfax, Loudoun and Prince William could be impacted through end of July

By: and - January 31, 2023 8:00 pm

Data centers in Ashburn, Virginia (Gerville / Getty Images)

With Dominion Energy anticipating possible problems supplying electricity to data centers in parts of Northern Virginia this spring, the state Department of Environmental Quality is proposing to ease certain air emissions rules for facilities in the zone to allow them to get extra power from generators.

In a statement announcing the proposal Thursday, DEQ Director Mike Rolband said the agency is “proposing this temporary and redundant variance out of an abundance of caution to maintain the reliability of the internet and the electric grid while enabling data centers to continue serving their customers.” 

The variance, which would be in effect between mid-March and July 31, would suspend certain short-term emissions limits for data centers if they sit in an area for which regional grid operator PJM has issued a warning about acute strains on the transmission system, the network of high-voltage power lines that transport electricity from where it is generated to smaller regional substations. 

The data centers would then be allowed to operate their emergency generators during the time period of the warning.

Aaron Proctor, a spokesman for DEQ, said the primary pollutants of concern associated with the generators are nitrogen oxides, with “lesser amounts” of particulate matter.

“We believe the variance’s impact to air quality, if any, would be marginal,” he said in an email, noting that since 2015, the duration of PJM warnings of the type that could trigger the suspension of emissions limits have averaged under 17 hours annually. 

“It is impossible to predict accurately what the potential emissions increase could be as a result of the variance because we don’t know how long warnings called during the term of the variance, if any, would last, or what specific geographic area any particular future warning would cover,” he said. 

Approximately 150 data centers in Prince William, Fairfax and Loudoun counties could be eligible for the variance, according to Proctor. 

That region, particularly the part of Loudoun known as Data Center Alley, is home to almost 300 facilities that contain the servers carrying roughly 70% of global internet traffic. It is the largest concentration of data centers in the world, followed distantly by Silicon Valley. 

While Virginia has actively courted further data center development through tax credits, accelerating growth of the industry in Northern Virginia has strained the ability of existing transmission power lines to carry the massive amounts of electricity these facilities require to operate into the areas where they are concentrated.

Today, Dominion says data centers account for roughly 20% of its total electric sales in Virginia. Much of the increase has occurred rapidly: Since 2019, the utility has connected nearly 70 new data centers in the area with over 2,600 megawatts of capacity — an amount equal to what’s needed to power roughly 650,000 homes. 

The expansion was flagged by gid operator PJM last January in its five-year forecast of the demand utilities should expect, which noted PJM had had to adjust its Dominion forecast “to account for substantial ongoing growth in data center construction.” 

In July, Dominion warned data centers in Ashburn it might not be able to meet power demands. After temporarily pausing connections for new data centers in Data Center Alley to analyze the area’s transmission system, the utility then began rolling out plans for a slate of improvements, including substation expansions and the construction of two new major transmission lines. 

Those improvements are expected to be completed over the next few years, but a gap between transmission capacity for data centers in the region and those facilities’ demand could remain through the end of July. No other businesses or residential customers will be affected. 

While the impacts of potential electricity shortfalls will be limited to data centers in Loudoun, Fairfax and Prince William, costs of new transmission projects are borne by all customers. 

Data center legislation

Legislation before the General Assembly this session aims to speed up the transmission upgrades Dominion is already planning. A bill from Sen. Lynwood Lewis, D-Accomack, would order state regulators to approve a set of projects identified by PJM as “Data Center Alley Improvements” no more than 270 days after the utility proposes them. Similar legislation has been put forward by Del. Matt Fariss, R-Campbell. 

A PJM committee this October recommended that the upgrades be done after finding that “numerous reliability violations” could occur in 2024 and 2025 due to data center demands. 

Upgrades underway by Dominion don’t take into account any future projects, such as plans by Amazon Web Services to invest $35 billion in expanding data center campuses across Virginia. A release from Gov. Glenn Youngkin’s office announcing the plans Jan. 20 said “numerous localities” are under consideration as sites for the new campuses, which “will be decided at a later date,” and said the expansions are expected to create at least 1,000 new jobs.

Dominion officials say any new data center development will require new transmission. 

The rapid growth of the facilities across Virginia has sparked increasing concern in Northern Virginia as centers have spread into Prince William and transmission constraints have emerged. 

Del. Danica Roem, D-Manassas, this session proposed a study of data center impacts on wildlife and natural resources, including air quality and groundwater, as well as electric reliability and ratepayer costs.

“Northern Virginia is already the data center capital of the world, and we need to know what we’re getting ourselves into with the expansion of an already booming industry that consumes a massive amount of water and energy and often requires substation and high-voltage transmission lines to supply it,” Roem said during a hearing on the resolution Monday.  

But while the bill garnered support from groups like the American Battlefield Trust and Virginia Conservation Network, it was opposed by the data center industry as well as the Youngkin administration. The proposal was scrapped on a 3-2 vote. A Senate version of the bill, from Sen. Chap Petersen, D-Fairfax, is still under consideration. 

Another bill from Roem, House Bill 1986, would have required the state to develop stormwater management regulations for data centers located near Manassas National Battlefield Park. DEQ Director Rolband and Meta both opposed the measure, saying it could have a chilling effect on the industry.

Petersen’s Senate Bill 1078 meanwhile would limit local governments to approving only those data centers sited in areas that “will have a minimal impact on historic, agricultural, and cultural resources” and won’t be within a mile of a national park, state park or “historically significant site.” It would also require governments to assess the project’s impact on water usage, carbon emissions and agricultural resources.

Del. Michael Webert, R-Fauquier, and Sen. Jill Vogel, R-Fauquier, have introduced bills that would lead to the undergrounding of transmission lines in their districts, following resident unhappiness over aboveground transmission lines linked to data center development. Both are advancing in their respective chambers.

But a similar proposal from Roem was killed by the House Commerce and Energy Committee Tuesday. 

“There’s a lot of issues surrounding this bill. A lot of people are very concerned about it,” said committee chair Kathy Byron, R-Bedford, before motioning to reject it. 


Our stories may be republished online or in print under Creative Commons license CC BY-NC-ND 4.0. We ask that you edit only for style or to shorten, provide proper attribution and link to our web site. Please see our republishing guidelines for use of photos and graphics.

Sarah Vogelsong
Sarah Vogelsong

Sarah is Editor-in-Chief of the Mercury and previously its environment and energy reporter. She has worked for multiple Virginia and regional publications, including Chesapeake Bay Journal, The Progress-Index and The Caroline Progress. Her reporting has won awards from groups such as the Society of Environmental Journalists and Virginia Press Association, and she is an alumna of the Columbia Energy Journalism Initiative and Metcalf Institute Science Immersion Workshop for Journalists.

Charlie Paullin
Charlie Paullin

Charles Paullin covers energy and environment for the Mercury. He previously worked for Northern Virginia Daily in the Northern Shenandoah Valley and for the New Britain Herald in central Connecticut. An Alexandria native, Charles graduated from the University of Hartford initially wanting to cover sports. He's received several Virginia Press Association awards for his coverage of crime, local government and state politics.