Virginia Legislature advances HB507 to cap data center generator emissions

The bill set forth by State Del. John Chilton McAuliff targets emission reductions from backup generators at data centers while also strengthening requirements for public notification, monitoring, and health assessments, according to the Virginia State House.

The legislation cleared both chambers and was officially enrolled as of March 30, 2026, passing the House by a 60-34 margin and the Senate with a 25-15 vote.

HB507 was introduced on Jan. 14, 2026, during the regular 2026 session, and the state legislature summarized it as: “Data centers; permit requirements, emission limits for certain engine-generator sets.”

Here is a summary based on the bill text, including clarification of its provisions as needed.

The new regulations limit data centers to operating carbon dioxide-emitting backup generators solely during emergencies, require those units to meet or exceed EPA Tier 4, or Tier 2 with selective catalytic reduction standards, and cap annual operation at 500 hours. Effective July 1, 2027, centers must use energy storage as the primary source of backup power for at least two hours before using such generators during grid emergencies. Further, the bill demands officials notify adjacent property owners when extended generator use is planned, mandates emission monitoring with monthly public reporting, requires air quality surveillance near sites with substantial generator clusters, involves the Health Department in cumulative health impact reviews, instructs notification of schools regarding certain local emission permit applications, and authorizes agencies to create regulations to enforce these rules.

House approval saw 59 Democrats and one Republican support the bill, with opposition from 34 Republicans.

Senate approval included 21 Democrats and four Republicans voting in favor, while 15 Republicans opposed the measure.

Primary sponsorship was by Del. John Chilton McAuliff (Democrat-30th District), Del. JJ Singh (Democrat-26th District), Del. Joshua E. Thomas (Democrat-21st District), and another co-sponsor.

McAuliff received his undergraduate degree from the University of Richmond in 2014.

A member of the Democratic Party, McAuliff was elected in 2026 to represent Virginia’s 30th House District, succeeding Geary Higgins as delegate.

In Virginia, the legislative process begins with a bill’s introduction in either the House of Delegates or the Senate, followed by assignment to committees for discussion or amendment. Once passed in committee, the legislation moves to the floor for debate and voting in both chambers. If both pass it, the bill goes to the governor for signature, veto, or allowance into law without a signature. Each year, the Virginia General Assembly meets in regular session beginning the second Monday of January, reviewing hundreds of bills, though not all are enacted.

Information in this article was obtained from the Virginia State House. The source data can be found here.