The Virginia Department of Environmental Quality (DEQ) is considering relaxing its restrictions on data centers using backup generators amid energy transmission concerns.

First reported by the Bay Journal, the DEQ announced this month it is considering the issuance of a variance (i.e. exception to general rules) that would provide data centers located in Fairfax, Loudoun, and Prince William Counties “a measure of relief” from existing regulations and permits that limit the use of Tier II and Tier IV emergency generators only during periods of a PJM-declared emergency.

“DEQ is concerned that the Counties of Fairfax, Loudoun, and Prince William is an area in which there may not be a sufficient amount of electricity for data centers due to severe, localized constraints in electricity transmission,” the department said. “A transmission constraint issue exists in the area which may affect the ability to provide enough electricity to data centers through 2025. In particular, the period between March and July 2023 has been identified as a time of potentially acute stress on the transmission capacity of the grid.”

DEQ said the proposed variance would authorize data centers' on-site generators to operate during times that fall short of a PJM-declared emergency but during ‘acute’ transmission constraints and strain on the electric grid.

“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 proposed various, data center operators much ‘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 come into effect following a 45-day comment period and will expire on July 31, 2023.

DEQ Spokesman Aaron Proctor told the Bay Journal that demand for electricity from data centers in affected counties "could potentially exceed the capacity of the area's electric transmission system" during that time period.

Proctor said the agency hopes the variance, once approved, will not be invoked and that it is "intended only as a precautionary measure."

DCD has reached out to DEQ and PJM for more information.

Update: A spokesperson for PJM told DCD: "Data center load growth in that area has the potential to cause system constraints.  PJM and Dominion are working to build out the transmission system to support this load growth. This proposal from the VA DEP would allow for data center on-site generation to run during limited circumstances to bolster reliability for existing customers as construction outages take place in the region."

A Dominion spokesperson told DCD: "We’re continuing to develop several near and long-term transmission projects to alleviate transmission constraints in eastern Loudoun. The first of the projects will be completed in late June. In the meantime and out of an abundance of caution, DEQ proposed the temporary variance as an additional tool for data centers in case it’s necessary. To be clear, transmission capacity is not constrained outside of “data center alley” in eastern Loudoun, and does not impact service to residential or small business customers, or any customers outside of the area. "

Get a monthly roundup of Power & Cooling news, direct to your inbox.