Ask the Expert

What Is the Status of the RICE NESHAP (Subpart ZZZZ) Following the 2015 Vacatur of Certain Emergency Engine Provisions?

Q: On May 1, 2015, the U.S. Court of Appeals for the District of Columbia Circuit issued a decision on 40 CFR Part 63, Subpart ZZZZ vacating the 100-hour exemption for emergency generators participating in demand response from having to meet the more stringent emission limits, control device requirements, and/or work practice requirements applicable to non-emergency generators. Does this court decision remain in effect or has it been modified in any way by the court or has the EPA issued new rules, or policy?

A: The decision issued by U.S. Court of Appeals for District of Columbia Circuit in May 2015 remains in effect.  On April 15, 2016, the EPA issued guidance on how the vacatur will impact certain regulatory provisions.  Nothing has changed since the EPA issued its guidance.  The vacated provisions remain “on the books” but as a result of the Court’s ruling they have no legal effect.  The EPA has indicated that there is no established timeline for revising the regulations.

The original regulation stated under 40 CFR 63.6640(f)(2) that an emergency stationary RICE may be operated for a maximum of 100 hours for any combination of:
i)        Maintenance checks and readiness testing;
ii)       Emergency demand response for periods that are declared an Energy Emergency Alert Level 2; and
iii)     Periods where there is a deviation of voltage or frequency of 5 percent or greater below standard voltage or frequency.

The Court’s decision vacates provisions ii) and iii), above, and the EPA’s guidance states that “an engine may not operate in circumstances described in the vacated provisions for any number of hours unless it is in compliance with the emission standards and other applicable requirements for a non-emergency engine.”