Virginia DEQ Proposes Allowing Data Centers to Run Diesel Generators Proactively During Spring, Summer Months

Environmentalists sat it will leave Northern Virginians breathing smog


Environmental groups are rallying against the Virginia Department of Environmental Quality's (DEQ) proposed variance that would allow regional data centers to run their generators in times of stress on the electrical grid as a preventative measure.

Residents will have the opportunity to comment on a proposed temporary variance for Northern Virginia data centers at a public hearing at 11 a.m. on Monday, Feb. 27 at the DEQ Northern Regional Office in Woodbridge, Va.

Diesel generators release pollutants into the air such as Nitrogen Dioxide [NO2], CO, VOC, SO2, which is why it is important they do not run too often. 

But DEQ now wants to allow data centers to run generators during the spring and summer months when there is a high demand on the electrical grid, in order to prevent such blackouts.  

The idea is to keep both the internet and the electrical grid up and running.

The provision is complicated by the fact that jurisdictions such as Prince William County have been approving (or are near to approving) data center campuses outside industrial zones. Large data center campuses are planned near homes, schools, and national and state parks. The result of this is that pollutants will not only affect people in industrial jobs but adults and children going about their daily lives.

Still, DEQ sees it as a necessity. 

“Northern Virginia is home to nearly 300 data centers that currently move approximately 70% of the world’s internet traffic,” said the DEQ press release. “These data centers require a significant amount of electricity to power their operations and cool their servers. An area in Fairfax, Loudoun, and Prince William counties has been identified in which data centers may not be able to obtain enough electricity due to transmission problems anticipated from March through July.”

The proposed variance would provide data centers in the affected counties “a measure of relief from limits that would be coordinated with the movement of wholesale electricity in Virginia."

“We are 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,” said DEQ Director Mike Rolband. “We will closely follow this developing situation and will use our robust compliance and permitting programs to ensure our environment remains protected.”

Under the variance, data centers must immediately notify DEQ when they are operating their on-site generators and must calculate and report the air emissions created by those generators during those times.

The variance will become effective upon signature of the DEQ Director following a 45-day comment period, including a public hearing, and will expire on July 31, 2023.  Public comments will be accepted in writing until March 14.

To view details of the public comment period and hearing, and provide electronic comments, please visit Town Hall at

Bristow Beat was unable to get in contact with a media contact at DEQ before publication but will continue covering this story to provide a vaster understanding of the issue. 

Environmental Opposition

The Piedmont Environmental Council, Sierra Club, Prince William Conservation Alliance, Coalition to Protect Prince William County, National Park Conservation Association and Protect Fauquier have organized a 10 a.m. media conference outside the DEQ building in Woodbridge. 

“We are opposed to the variance which seems to give the data center industry in Northern Virginia carte blanche when it comes to air pollution from March 15 to July 31st,” said Julie Bolthouse Director of the PEC.

“We are also disappointed that DEQ has not even provided an analysis or information on potential public health and environmental impacts of approving the variance. If the variance is approved, we believe DEQ at least needs to provide more analysis and establish some guardrails, require real-time monitoring of pollutants, and establish an alert system that notifies residents of affected communities when generators will be running so they can take precautions.”

The key concerns among environmental groups include processing issues.

“The DEQ has not provided reasonable outreach or notice to the affected localities, given enough information on this proposal in a readily accessible format, or adequately evaluated the public health and environmental impacts of this proposed variance.”

Excessive Scale and Scope of Variance.

The variance will apply to 101 air pollution permits in Northern Virginia. The permits cover 4,632 commercial generators with a rated capacity of 11 gigawatts in total. For comparison, the nuclear facility at Lake Anna has a rated capacity of 1.8 gigawatts.”

Health Impacts.

The data centers covered by this permit are clustered in areas in close proximity to communities, schools, parks, and recreational facilities. In the Ashburn/Sterling cluster (data center alley) which the W&OD trail goes through, there are 2,856 generators.

In the Manassas cluster near several parks and schools, there are 842 generators.

All of these generators run on diesel and release NO2, CO, VOC, SO2, and PM10/2.5 which have known health impacts, especially on vulnerable populations like children and elderly.” 

And finally Environmental Impacts.  

“The emissions from diesel generators are known to be harmful to the environment, contributing to ground-level ozone, causing acid rain, and releasing greenhouse gasses that warm the planet and alter the climate.” 

Health Impacts on the Community 

According to the EOHHA California, diesel exhaust is a mixture of thousands of gases and fine particles, or “soot,” that contain 40 toxic air contaminants, of which many are cancer-causing substances such as benzene, arsenic and formaldehyde."

Exposure through breathing or on the skin leads to higher health risks over both the short-term and long-term, including certain cancers. It can also cause immediate health effects.

“Diesel exhaust can irritate the eyes, nose, throat and lungs, and it can cause coughs, headaches, lightheadedness and nausea. In studies with human volunteers, diesel exhaust particles made people with allergies more susceptible to the materials to which they are allergic, such as dust and pollen. Exposure to diesel exhaust also causes inflammation in the lungs, which may aggravate chronic respiratory symptoms and increase the frequency or intensity of asthma attacks.”

“Like all fuel-burning equipment, diesel engines produce nitrogen oxides…Nitrogen oxides can damage lung tissue, lower the body's resistance to respiratory infection and worsen chronic lung diseases, such as asthma. They also react with other pollutants in the atmosphere to form ozone, a major component of smog.”

The elderly, and people with emphysema, asthma and chronic heart and lung disease are especially sensitive to fine-particle pollution as are children because their lungs are still developing. It can increase the frequency of childhood illnesses and can also reduce lung function in children.

In Prince William County data centers are planned next to elementary schools and 55+ living communities. 

The study "Using backup generators for meeting peak electricity demand: a sensitivity analysis on emission controls, location, and health endpoints"  notes that “generators installed for backup power during blackouts could help satisfy peak electricity demand; however, many are diesel generators with nonnegligible air emissions that may damage air quality and human health.” It advises companies to adopt cost-effect mitigations to protect public health, while weight the cost-benefit in terms of dollars and cents.

“On a full cost basis, it was found that properly controlled diesel generators are cost-effective for meeting peak electricity demand…These air quality changes were translated to their equivalent human health effects using concentration-response functions and then into dollars using estimates of ‘willingness-to-pay’ to avoid ill healthThe cost was $2 per KiloWhatt verses 10 cents per kiloWht without any mitigations to protect public health,” said the abstract.

Who could have known? 

Air quality was hardly even part of the conversation regarding data centers being built near homes, schools, and parks because people were told generators would only run in emergency situations. Still, environmentalists have advocated that Virginia tighten its regulations in regard to backup generators.

In an OpEd piece in the Virginia Mercy dated Feb. 15, the Sierra Club’s Ivy Main explained that elsewhere outside Virginia, data centers were using clean energy and storage or installing microgrids “capable of providing all of the power the facility needed.”

 Years prior she urged the DEQ to require data centers to have generators that would run on solar and batteries as a “first line of defense." 

“Yet DEQ rejected the suggestion and gave the go-ahead for the data center to install 139 diesel generators with no pollution controls,” said Main.

“Three years later, data centers have proliferated to such a degree that the power grid can’t keep up. DEQ is now proposing that more than 100 data centers in Loudoun, Prince William and Fairfax counties be given a variance from air pollution controls so they can run their diesel generators any time the transmission system is strained.”

Support for the Variance

The Virginia Chamber of Commerce supports the variance, posting this statement in support of the amendment. 

“The variance proposed by the Department of Environmental Quality is limited in both scope of geography and duration to address the electrical transmission capacity constraints within eastern Loudoun County between the months of March and July."

"These limitations are well-crafted and will enable regulators and industrial partners alike to be intentional and measured in implementing policies without introducing unnecessary risk or emissions."

"Importantly, any utilization of the variance will be optional and contingent on notice from utility providers to ensure that generators will be subject to active monitoring, reporting and regulatory oversight during any limited periods of run-time. These guardrails will ensure that industry and utility partners communicate and coordinate effectively while collecting critical data required to further strengthen the grid.”

The chamber goes on to say that Virginia is a global leader in the data center industry and while it does not have a "Demand Response" as California and Texas do, this is a step forward. 

Response from the Community

Dr. Steve Pleickhardt, President of the Amberleigh Station HOA, responded to the chamber’s stance in an email, Friday, horrified that they would side against residents. 

“My HOA is incensed about the comment below to allow diesel generators to run during critical energy shortages for data centers! I’m sure none of your members have data centers 100 feet from their homes and wouldn’t want to risk their health by inhaling small diesel particulates.”

His residents now fear their community will also be damaged by “scores of diesel generators that will engulf our residents in plumes of pollution and noise. It is an OUTRAGE that you have such a stance regarding the health of tens of thousands of residents of Virginia!”

In a Facebook Live video, Friday, Going Gainesville talked to the newly elected Gainesville Supervisor Bob Weir about the data center propagation, the electrical grid and the generator variance.

He explained running generators would be no small thing. 

“I just looked at one of these plans for a data center yesterday and there’s 100 diesel generators, and we’re not talking the little ones you put in your garage, we’re talking these semi-truck sized diesel generators. Can you imagine living next to one of those? It would be like living next to a truck stop with the trucks coming in 24/7.”

He is opposed to the variance mainly because of the health risks and the fact that, at least in Prince William County, data centers have been improperly sited outside of industrial-zoned areas. 

“I’m not an ecowarrior but one of my children has severe asthma and I can’t imagine what someone with asthma or allergies is going to be like on a code red day when they fire up 100 generators," said Weir. “Quite frankly, it’s something the General Assembly needs to address.”

Weir explains that the grid cannot sustain the number of new data centers planned in the region. 

“It’s going to reach critical mass. It’s going to reach critical mass sooner than I think anybody realizes and there is going to have to be some action taken. What that action is, I don’t know. It is going to be interesting.”

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