This summer, a fire at an electrical substation forced data centers in Loudoun County to rely on backup diesel generators, leading to noise and diesel fumes complaints from a nearby Walmart parking lot.
Loudoun County Supervisor Mike Turner, representing the Ashburn area known as “Data Center Alley” for its high concentration of facilities, received numerous complaints via email during the incident.
Turner remarked on the diesel generators, labeling them as “filthy” due to their operation for several days. “As soon as they start running their backup generators, we start getting complaints,” he said.
New guidance from Virginia’s Department of Environmental Quality (DEQ) may expand conditions allowing data centers to use these generators next year, raising air and noise pollution concerns.
The DEQ guidance, detailed in a memo, redefines emergencies to include “planned outages,” allowing the use of Tier II generators more frequently.
Currently, Tier II generators are permitted only during unforeseen events like power outages or natural disasters. Cleaner Tier IV generators can operate outside emergencies but are costlier due to advanced emission-control technology.
Dominion Energy, the state’s largest utility, did not comment on the DEQ guidance. The Data Center Coalition supports the new definition for continuous power requirements.
According to a report, Virginia has about 9,000 generators, with 4,700 in Loudoun County. Around 8,000 are Tier II generators, which produce pollutants like nitrogen oxides and particulate matter. These substances are linked to health issues, including cardiopulmonary death.
The legislative report indicates that in a worst-case scenario, backup generators could emit 9,000 tons of nitrogen oxides, roughly half of Northern Virginia’s annual emissions.
Virginia’s need for grid transmission upgrades is driving the push for flexible generator use. More than 100 are planned to supply data centers, often requiring temporary outages.
Some environmental groups are requesting a 30-day extension to comment on the guidance, which could still be under review when governor-elect Abigail Spanberger takes office. Her stance on diesel generators remains unclear.
Battery storage systems are a possible alternative, but they take up significant space and only provide power for about four hours before needing a recharge.
“I am not surprised,” Turner said regarding DEQ’s memo. “With a constrained grid in Loudoun County, it makes sense for DEQ to widen the scope of emergencies for generator use, though I’m unsure if I agree.”
The potential increase in diesel generator use could impact air quality, particularly on hot days, said Jeff King from the Metropolitan Washington Council of Governments. Understanding the full emissions impact is challenging without complete data.
Recent reports suggest ratepayer savings could be achieved by reducing grid energy use, a development closely watched by the Piedmont Environmental Council.
Original Story at insideclimatenews.org