The Connection

Members of Chantilly’s Pleasant Valley community did all they could last week to convince the Fairfax County Planning Commission that allowing construction of a huge data center near their homes would be a terrible idea. They researched every aspect of the potential problems this use could cause, spoke passionately, made fact-based arguments, presented charts and data, and even had an acoustics expert testify remotely.

The commissioners listened intently during the nearly five-hour public hearing last Wednesday, Sept. 20, seemed genuinely concerned and asked a multitude of questions. But in the end – even though the applicant didn’t provide them with all the information they requested, and some huge questions still remain – they voted to approve it.

“The key issues for me are sightline and the constant noise,” said Planning Commission Chairman Phillip Niedzielski-Eichner. “But it’s not adjacent to the neighborhood, and if it’s 40 decibels [at the community’s edge] before it’s operational, it’s OK. But I’m not happy with the way this was handled by the applicant.”

Penzance wants to build a 402,000-square-foot data center off Route 50, Stonecroft Boulevard and Auto Park Circle in Chantilly. It’s adjacent to the Cub Run Stream Valley and just 4/10 of a mile from Pleasant Valley.  

The land’s zoned part commercial and part industrial, so Penzance needs it all rezoned industrial. It’s also seeking a special exception so the data center could be as high as 110 feet, including 27 rooftop diesel generators. 

It would arise on 12.1 acres of a 79-acre parcel, with the remaining 67 acres dedicated to the Park Authority and preserved as a Resource Protection Area (RPA). Some of the questions the applicant refused to answer include 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. 

Indeed, according to Business Insider, “Data centers consume quantities of power so vast they have begun to tax entire energy grids. Amazon operates or is in the process of planning and building 102 data centers in Northern Virginia alone. Together, [they] require more energy to keep running than the entire city of Seattle.” 

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 Commissioners otherwise.

“The noise level would be above and below 50 decibels, 50 percent of the time,” said Pritchard. We’re committing to pre- and post-construction noise tests. He also contended that, because of mitigation efforts, the noise would be equivalent to “the running of a quiet dishwasher.” And because the generators will be screened, he added, “Noise will be no greater than 75 decibels at a distance of 25 feet. And generator testing will be limited to 9 a.m.-9 p.m., for no longer than two hours total at a time.”

Pritchard said there’d be “adequate access” for trucks to enter via Route 50 and “We’ll construct a right-turn, deceleration lane off eastbound 50 onto the property.” He also said the 110-foot height includes all rooftop equipment.

Residents are concerned about potential fuel leaks from the 27 onsite 500-gallon diesel-fuel storage tanks, plus the 5,000-gallon base tanks each generator would have – especially because any fuel entering Cub Run Stream (which flows into the Occoquan Reservoir) could pollute the drinking water for the entire county.

But, said Pritchard, “If there’s a spill, the land will be graded so it’ll flow away from the RPA or stormwater facilities and be contained in an oil/water separator and other equipment. And monitors will sense any leaks and alert the center’s operator. There’ll be overfill-protection valves, and we’ll do any necessary pre-treatment of water before it enters the wastewater.”

The generators will run during maintenance and emergencies, and when the data center needs more electricity from the grid. Noting that there previously was a five-day power outage, Commissioner John Ulfelder (Dranesville) asked, “What happens if the power goes off for five days? That’s a pretty long time for the generators to be running.”

“The tanks have enough fuel for 24 hours,” replied Civil engineer Jamie Cox. “If there was a power outage, we’d have to have fuel deliveries.”

Commissioner Daren Shumate (Mason) asked if the center could really meet 50 decibels at the Pleasant Valley property line. Pritchard said yes, adding that one study showed 42 decibels there. But when Shumate asked if that number also included noise from Route 50, the car dealerships and overhead planes, Penzance’s sound engineer, Sam Williams, said it was “just the building.” He also said the cooling units would have various silencers around them.

Regarding the height, Pritchard said they flew a drone overhead at 110 feet and concluded the center would only be visible from a “handful” of Pleasant Valley homes. “Did you announce the day and time of the drone flight for the community to see?” asked Commissioner Mary Cortina (Braddock). 

Pritchard said they invited county staff, but not the residents, because of their objections to the center. “But nobody could see a speck of a drone,” replied Cortina. “A balloon would have been more visible.”

Niedzielski-Eichner expressed disappointment that Penzance “didn’t include the community most affected” and wondered, “Can we have confidence in the drone visual as accurate?”

Cortina asked where the electric substation would be, but Pritchard said Dominion asked him not to tell. Saying a use of such density requires “adequate infrastructure in place – and we don’t know where it’ll be,” Cortina said, “Usually, Dominion has to provide this information.”

Furthermore, when Ulfelder asked what the air-quality impact would be from the 27 generators, Pritchard said they’d meet EPA and DEQ regulations, but didn’t know what types of generators they’d be. Ulfelder then wondered what the impact would be “to the homes less than half a mile away.”

Noting “natural gas has less potential for risk than diesel fuel and would seem to be better,” Niedzielski-Eichner asked why it’s not an option for the generators. Pritchard simply replied the prospective tenant told Penzance to expect diesel with catalytic converters. 

And when Niedzielski-Eichner asked about a data center’s potential impact on water in the environment, a county water representative said the county doesn’t have enough data on salt concentrations in water from data centers and is trying to get it.

Prior to the vote, Ulfelder said, “There are some open questions that trouble me. This is different and massive and is a change not necessarily intended for that area, so I’ll abstain.” Citing a lack of information, Cortina did likewise, as did Pete Murphy (Springfield).  Vice Chairman Timothy Sargeant, who’d disclosed a professional connection to Dominion at the outset, had recused himself.

Ultimately, although the commissioners asked county staff if they could defer decision on this issue, they were told a deferral would go forward to the Board of Supervisors (who’ll hear it Oct. 24) as an approval. And since they were on day 98 of a 100-day time limit from the staff report’s publication, they went ahead and voted.

Saying he designs data centers, Shumate said strict environmental regulations would prevent this one from having an environmental impact. “It’s a tall building, but quite a way from the community,” he said. “And the applicant said the noise would be 40 decibels from the edge of the community, so I’m satisfied.”