Supervisors to Decide on Chantilly Data Center

Supervisors to Decide on Chantilly Data Center

Public hearing is set for next Tuesday, Jan. 23.

Artist’s rendition of the proposed data center in Chantilly. See white car on left in comparison to the building’s height.

Artist’s rendition of the proposed data center in Chantilly. See white car on left in comparison to the building’s height.

How to Comment to the Board on this Data Center

* To speak at the Jan. 23 Board meeting, fill out and submit the form at Speakers must sign up before noon on the day of the hearing. 

* Or submit written testimony, including attachments, to Case numbers to reference are RZ 2022-SU-00019 and SE 2022-SU-00038. 

* Letters may be mailed to the Department of Clerk Services at 12000 Government Center Parkway, Suite 552, Fairfax, VA 22035. Or email them to Board Chairman Jeff McKay at or to Supervisor Kathy Smith (D-Sully) at, since the proposed data center is in the Sully District. Emails may be sent, as well, to individual supervisors from other districts.  

* To submit a video, go to All videos must be submitted by Monday, Jan. 22, at 9 a.m.

* To testify by phone, people must sign up first and may call in during the hearing at 703-324-1020. Land lines work best, though, because the county’s audio system often makes cell phones difficult to hear.

“Increased electricity demand also increases greenhouse gas emissions, which may make it harder to meet the state and county greenhouse-gas emission- reduction goals.” 

— Fairfax County DATA CENTERS Report and Recommendations, Jan. 9, 2024

In September 2023, members of Chantilly’s Pleasant Valley community presented facts, charts, data and expert testimony to the Fairfax County Planning Commission. A gigantic data center is proposed for construction just 4/10 of a mile from their homes, and they explained in great detail all the harm it could cause to them and to the environment. 

Ultimately, though, the Commissioners recommended approval, and the matter now goes to the Board of Supervisors for a public hearing and decision, next Tuesday, Jan. 23, at 4 p.m. (although it could start later). 

Knowing that the Supervisors are eyeing the potential $6 million in revenue this data center could bring the county, the residents opposed to it realize they’re facing an uphill battle, but they’re still determined to fight. And they hope others will join them by either emailing the supervisors or signing up to testify at next week’s hearing at the county Government Center in Fair Oaks. (See information at end of story).

“The threat to our environment and drinking water is real,” said Kate Maisal. She and many other residents are worried about the continual delivery and storage of thousands of gallons of diesel fuel to this data center that would occur in a stream valley upstream from the Occoquan Reservoir – the drinking-water source for much of Fairfax County.

The Sierra Club’s Ann Bennett said the data center hasn’t incorporated adequate sustainability and clean-energy measures. Acoustics engineer Braxton Boren said its relentless 24/7 hum would harm residents’ quality of life. And the joint Sully District Council/West Fairfax County Citizens Association Land-Use Committee decried the fact that consumers – and not the applicant – will foot the bill for the new electric substation and transmission lines required to support this facility. 

Penzance wants to build a 402,000-square-foot data center off Route 50, Stonecroft Boulevard and Auto Park Circle in Chantilly. It would also be adjacent to the Cub Run Stream Valley. It would be constructed on 12.1 acres and could be as high as 110 feet. 

Its components include 27 diesel generators in an enclosure on the rear/Pleasant Valley side of the building, plus a rooftop HVAC system that would emit the constant hum Boren noted. And so far, Penzance has refused to answer who the data center user would be, exactly where the electric substation needed to power it would go, and how much water and electricity it would consume. 

Many residents in Centreville and Chantilly alike are opposed because of the massive size, noise, truck traffic and air, water and soil pollution this center could bring. But land-use attorney Evan Pritchard, representing the applicant, persuaded the Planning Commissioners otherwise.

Now, though, it seems as if county staff itself has several serious concerns about data centers, the way they’re approved and the dangers they pose. 

In May 2023, the Board of Supervisors directed staff to provide a report on data centers – complete with research, findings and recommendations. After completing its extensive investigation, staff released a report dated Jan. 9 containing its findings.

It noted that the large energy demand of data centers warrants several concerns:

* The availability and reliability of energy for existing and planned development; 

* The potential need for clearing and construction of new major transmission lines and substations and related costs relayed to rate-payers; and

* Potential water quality and air quality impacts of large numbers of diesel backup generators.

Furthermore, the report stated that “increased electricity demand also increases greenhouse gas emissions, which may make it harder to meet the state and county greenhouse-gas emission- reduction goals.” And once constructed, both data centers and their electric substations “can have visual and noise impacts and, depending on their location, impacts on natural resources and environmentally sensitive areas.”

Among the report’s recommendations are that “consideration could be given to amending the [county’s] Noise Ordinance for data centers with large numbers of backup generators to remove the exemptions for testing and maintenance of generators, as well as the full emergency use of backup generators.”

It also noted that “a review of noise studies submitted as part of rezoning or SE [special-exception permit] applications for data center projects in Fairfax County indicated that measures were consistently needed to reduce the potential noise to comply with the Noise Ordinance.”

The report stated that the county Zoning Ordinance should “consider revising permissions to require SE approval for data centers, regardless of size, in the C-3, C-4 and I-2 through I-6 Districts. It further suggested that standards for special-exception review should include the consideration of the size of a proposed data center and its distance (buildings and generators) from surrounding existing and planned residential development.”

The report stated that some of its recommendations – “such as a review of noise studies and building design and encouraging increased open space, tree planting and stormwater treatment – may be more effectively implemented through an SE review.”

And it recommended that the county’s Comprehensive Plan could consider “recommendations for enhanced buffering for data centers located near

residential, noise sensitive uses and environmentally sensitive areas.” It also suggested establishing “guidelines for distances from existing or planned substations or transmission lines that can service the data center.”

Read the report at

So now that the supervisors have all these new recommendations in hand – and they haven’t yet voted to approve the Chantilly mega data center, local residents are wondering what’s the rush – and why this application can’t be voted on later, after it can be determined if it meets staff’s recommendations?

After all, said resident Donna Jacobson, “A responsible government should want to make sure any data center is built using the highest standards to safeguard residents.”