The Prince William Chamber of Commerce submits the following comments regarding the Virginia Department of Environmental Quality’s updated guidance—APG-578—which clarifies when emergency generators may be used during planned electrical outages. This clarification is important to the continuity and reliability of operations for businesses, institutions, and essential services across Prince William County and the Commonwealth.
Under existing DEQ regulations, “emergency” generator operation is permitted during a “failure of the electric grid,” but only when the failure results from “sudden and reasonably unforeseeable events” outside the operator’s control. Historically, DEQ has not allowed generators to operate during planned (scheduled) outages because businesses theoretically have sufficient advance notice to implement alternative solutions without relying on emergency units.
However, DEQ recognizes that in many real-world scenarios, businesses often receive insufficient notice of a planned outage—sometimes less than two weeks—and therefore cannot reasonably secure temporary power sources or reconfigure operations to avoid disruption. In these circumstances, use of on-site emergency generators is both necessary and appropriate to maintain critical operations.
APG-578 refines the definition of “sudden and reasonably unforeseeable” to include planned outages when notice is 14 calendar days or less, provided that appropriate notifications, record-keeping, and reporting requirements are satisfied. This guidance does not authorize violations of any air-permit conditions, but instead clarifies a previously ambiguous regulatory interpretation.
The Prince William Chamber of Commerce supports this guidance because it offers a pragmatic, common-sense interpretation that strengthens operational continuity across the private, nonprofit, and public sectors. We respectfully submit the following comments:
1. Emergency generators are critical for continuity of operations
Emergency generators are deployed across the economy—including in manufacturing facilities, hospitals, schools, data centers, public safety sites, and countless private businesses. Their purpose is to ensure safety, protect equipment, preserve data, and maintain essential services when grid power is unavailable.
2. The regulatory definition of “emergency” reflects real-world operational risk
The existing regulations correctly define emergencies as “sudden and reasonably unforeseeable events” outside the operator’s control. Planned outages with limited notice effectively function the same way for businesses that do not have practical alternatives.
3. Utilities often provide limited or no advance notice of maintenance-related outages
Power suppliers must schedule maintenance based on system conditions and infrastructure needs, and these activities can be scheduled quickly. As a result, businesses frequently receive short notice—far less than would be needed to design or deploy backup systems other than their on-site emergency generators.
4. Temporary generator deployment is impractical, costly, and may increase emissions
When outages affect a large number of operations simultaneously:
The guidance appropriately recognizes these operational constraints.
5. APG-578 provides a balanced, practical regulatory interpretation
The guidance:
This is a reasonable, protective, and economically responsible approach.
The Prince William Chamber of Commerce appreciates DEQ’s thoughtful refinement of the emergency-use provisions for generators. APG-578 strikes the right balance between environmental protection and operational practicality for businesses across the Commonwealth. By acknowledging the limitations posed by short-notice planned outages, DEQ has provided clarity that supports business continuity, public safety, and economic stability.
We respectfully support this guidance and urge its continued implementation.