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This past summer, a fire at an electrical substation forced data centers in Loudoun County to rely on backup diesel generators as their power source.
Grid failures like this happen often, but this time, shoppers in a nearby Walmart parking lot heard the noisy generators start up and reported smelling diesel fumes.
“People were like, ‘What is going on?’” said Julie Bolthouse, the director of land use for the Piedmont Environmental Council, an environmental nonprofit fighting data center sprawl. “This sounds like planes landing constantly for over 24 hours.”
Loudoun County Supervisor Mike Turner, who represents the Ashburn region known as “Data Center Alley” because it is home to the world’s largest concentration of the facilities, said email complaints flooded his inbox during the incident.
“Frankly, they’re filthy,” Turner said of the diesel generators that had to run for four or five days. “As soon as they start running their backup generators, we start getting complaints.”
Now, new guidance from the state’s Department of Environmental Quality (DEQ) may expand the circumstances under which data centers could use their backup diesel generators next year, raising concerns among residents and environmentalists about air and noise pollution.
“Any increase in how often they’re running is going to cause corresponding localized air pollution,” said Tyler Demetriou, an associate attorney with the Southern Environmental Law Center.
The DEQ guidance surfaced in a Sept. 30 memo from Mike Dowd, director of the Air and Renewable Energy Division, to Director Michael Rolband. It expands the definition of an emergency, allowing for the use of the diesel generators, known as Tier II generators.
Currently, Virginia’s regulations allow Tier II generators to operate only in emergencies, generally defined as “sudden and reasonably unforeseeable” events, including power outages or natural disasters. Cleaner-burning generators, known as Tier IV generators, can run outside of emergencies, but their emission-control technology is more costly.
The new guidance would add a “planned outage” scheduled by a utility to the list of emergencies when dirtier, cheaper Tier II generators could run. DEQ uses a scenario in which notice of an outage is provided within 14 days or less.
“In light of this analysis, DEQ considers that an electric outage may sometimes be a ‘sudden and reasonably unforeseeable’ event,