Virginia Tightens Air Permitting for Data Center Backup Generators with Tier 4-Equivalent Emissions Limits

Virginia has adopted new air emissions requirements for data center backup generators, marking a significant shift in how the Commonwealth regulates one of the fastest-growing sources of stationary diesel engine emissions. The new rules, which apply to air permit applications submitted on or after July 1, 2026, require that each engine-generator set meet emissions performance equivalent to a Tier 4-certified unit, and they carry substantial implications for generator selection, permitting strate