DOEE Proposes Amendment for Opacity Limits for Fuel-Burning Equipment

Environmental Consulting

March 23, 2023

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On May 12, 2023, the Department of Energy and Environment (DOEE) proposed amendments to Chapter 6 of the District’s air quality regulations. This action is in response to the United States Environmental Protection Agency’s (EPA’s) 2015 call for revisions to several State Implementation Plans (SIPs) to address periods of startup, shutdown and malfunction (commonly referred to as “SIP call”).

In response to the SIP call, DOEE is proposing stricter limits for opacity during periods of startup, shutdown and malfunction. The current visible emission standards allow for opacity of up to 40% for twelve minutes per day regardless of type of operation or emission unit. DOEE is proposing to revise this to lower opacity standards that will vary by equipment and fuel type and to only allow these increased visible emissions during startup, clean, adjusting of combustion controls, or regeneration of emission control equipment.

Limits Vary by Equipment Usage

At all other times, the visible emission standard of 0% will continue to apply. DOEE is requesting comments, including technical justification, on the proposed opacity limits for these events. The proposed language includes multiple limits for several categories as shown in the table below. Limits range between 20% and 40% and final limits will depend on comments received.

Table 1.

Emission Unit	Visible Emissions Standard Permitted for Two Minutes during any Startup, Cleaning, Adjustment of Combustion or Operational Controls, or Regeneration of Emission Control Equipment
Fuel-Burning Equipment when burning exclusively Natural Gas	20%, 27% or 40%
Fuel-Burning Equipment when burning Fuel Oil or a Combination of Fuel Oil and Natural Gas	27% or 40%
Fuel-Burning Equipment for All Other Cases including Burning Coal	27% or 40%
Combustion Turbines	20%, 27% or 40%
Asphaltic Concrete Production Equipment	20% or 40%
Stationary Engines	27% or 40%
Nonroad Engines	27% or 40%
Cooking Equipment	20% or 40%
All Sources Not Specified	27% or 40%

DOEE is also removing the affirmative defense provisions from the regulation which was specifically noted in the SIP call.

Opacity Compliance Regulation Issues

In addition to addressing the SIP call, DOEE is also taking this opportunity to address some other known compliance issues with the existing opacity regulations.

First, DOEE is proposing an alternate limit for emission units demonstrating compliance using a continuous opacity monitoring system (COMS). Due to the sensitivity of COMS, the 0% opacity standard has caused compliance issues for these sources. DOEE is proposing to increase the opacity standard for normal operations to 5% for any source using a COMS. Note that sources that began operation before January 1, 1977, will still be subject to an opacity standard of 10% regardless of using a COMS.

DOEE is also clarifying that visible emissions limits apply to nonroad engines. This is not a change in applicability. Although the current regulation does not specifically state that it applies to nonroad engines, DOEE’s compliance and enforcement group have applied the standard to these sources historically.

Lastly, DOEE is adding recordkeeping provisions including logs of the date, time, and duration of any equipment startup, manual shutdown, combustion control adjustment, emission control regeneration, and malfunction. These logs are required for all such events regardless of visible emissions. These requirements apply to all fuel-burning sources including nonroad engines.

Regulation Next Steps

There is no proposed effective date in the regulations indicating that the changes would become effective immediately once the regulation is finalized. Permits issued by DOEE since the SIP call was issued have included language that permit conditions will be superseded by this regulation once it is finalized. However, all fuel-burning equipment, regardless of containing such language in a permit, and even equipment not required to have a permit, will be required to comply with this regulation.

The proposal can be found here. Anyone interested in providing comments on the proposed amendment must do so by 4:00 PM on Monday, June 12, 2023. Comments may be mailed/hand delivered to DOEE or email comments to [email protected]. DOEE will also be holding a hearing on June 12, 2023, at 5:30 PM. The hearing will be held virtually; links and phone number to join are included in the proposed rule.

Trinity Consultants’ Washington, D.C. Office is experienced in assisting clients with air quality regulations in the District and has two Method 9 certified visible emissions observers. Please contact our office at 240.379.7490 if you have any questions or concerns regarding the proposed regulation and its potential impact on your operations.

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