On December 15, 2023, the District of Columbia Department of Energy and the Environment (DOEE) proposed to renew and revise the existing source category permits to construct and/or operate diesel and natural gas-fired emergency engines. These revised source category permits are applicable to a subset of engines that are subject to the federal New Source Performance Standard (NSPS) Subpart IIII and Subpart JJJJ. These permits are currently set to expire on September 26, 2024. For engines not subject to the NSPS regulations, DOEE has separate source category permits which are valid through September 29, 2025, and will not be impacted by this action.
Diesel-fired emergency engine owners and operators must seek coverage under air quality source category permit No. 7048-SC-R2 for new and existing emergency engines in the District of Columbia subject to NSPS IIII. Meanwhile, natural gas-fired emergency engine owners and operators will be required to apply for coverage under air quality source category permit No. 7043-SC-R2 for engines subject to NSPS JJJJ. These revised permits establish a new five-year duration for each source category permit and are proposed to expire on January 16, 2029.
There is no change in applicability for the source category permits, and the majority of the permits are unchanged. However, there were some changes to the permits to reflect changes to DC environmental regulations that have become effective since the permit was last issued. The most notable change to the permits is the inclusion of language to incorporate revisions to the District’s visible emissions regulations in Title 20, Section 606 of the District of Columbia Municipal Regulations (20 DCMR 606) and the District’s revised regulations odor regulations in 20 DCMR 903.
In both of the new permits, Condition III(b) has been amended to require that visible emissions be limited to 27% (unaveraged) opacity during a permissible event, such as start-up, cleaning, adjustment of combustion or operational controls, or regeneration of emissions control equipment. This is a significant reduction from the 40% (unaveraged) opacity limit set in the previous permit. The new permit also removes the twelve-minute aggregate allowance of engine discharges within any twenty-four-hour period. Instead, discharges shall be permitted for a maximum of two minutes total. Additionally, this two-minute limit no longer includes malfunction of the equipment as a permissible event in the new permit. This is consistent with changes to 20 DCMR 606 which became effective on August 11, 2023, which already apply to emergency generators in the District.
The removal of equipment malfunction as a permissible event is covered in greater detail in Condition III(c). The new permit clarifies that a malfunction shall not be considered unavoidable if the owner or operator could have taken, but did not take, appropriate steps to eliminate the malfunction within a reasonable time, as determined by the Department. This revision requires that owners and operators of applicable emergency engines provide evidence that any given malfunction was unavoidable.
The changes to the District’s odor regulations (20 DCMR 903) were largely the addition of requirements for odor control plans for certain sources. Emergency generators are not subject to this portion of the regulation. As such, the changes to odor requirements are minimal and general in natural despite the 2023 changes to DC’s odor requirements.
Once the new permit is issued, no new applications for coverage under the old permit will be accepted and any applications to cover new engines will need to use the new form and will receive coverage under the new permit. Engines operating under one of the current source category permits must submit a renewal application by June 26, 2024. For both new and existing generators, the permit application fee will be $500 or $1,000 depending on the engine size. At this time, DOEE is issuing invoices once an application is submitted; the 45-day approval clock for a source category permit does not begin until payment is received.
The draft application forms and permits (available for review and comment) can be found below:
- Draft Permits and Application Forms:
- Public Notices
The draft source category permits were posted December 15, 2023, and are available for public comment for 30 days (January 16, 2024). Trinity has been assisting clients with air quality permitting in the District of Columbia for over two decades. If you need assistance in determining if these source category permits could apply to your operations or would like assistance in reviewing the revised source category permits, please contact
Trinity’s DC office at
240.379.7490.
