Notice of Public Comment Period - Draft Air Quality Permit 6576-R1 - Architect of the Capitol, U.S. Capitol Power Plant

PUBLIC NOTICE

Draft Air Quality Permit 6576-R1, Architect of the Capitol, Operation of an existing 203 MMBTU/hr dual fuel-fired (natural gas and No. 2 fuel oil) boiler (Boiler 3) at the U.S. Capitol Power Plant, 25 E Street SE, Washington DC

Notice is hereby given that, pursuant to 20 DCMR § 210, the Air Quality Division (AQD) of the Department of Energy and Environment (DOEE), located at 1200 First Street NE, 5^th Floor, Washington DC, proposes to issue air quality permit No. 6576-R1 to the Architect of the Capitol (AOC) to operate an existing 203 MMBTU/hr dual fuel (natural gas and No. 2 commercial fuel oil) boiler, designated Boiler 3, at the U.S. Capitol Power Plant (CPP), 25 E Street SE, Washington DC 20003. The contact person for facility is Christopher Potter, Director, Utilities and Power Plant Operations, at (202) 641-6651 or [email protected].

In addition to standard permit issuance, with this action, DOEE is proposing to submit, to the U.S. Environmental Protection Agency (EPA), the requirements contained in Conditions II(b) and (c) (emission limits) and III(b) (limits on fuel usage) of the draft permit for inclusion in the District’s State Implementation Plan (SIP), located at 40 CFR 52, Subpart J. DOEE is proposing to include the requirements of these permit conditions in the SIP in order to ensure federal enforceability of the Alternative NOx RACT Plan, dated August 2024, submitted by AOC pursuant to 20 DCMR § 805.2. In a separate action, on April 25, 2025, DOEE proposed to accept AOC’s alternative NOx RACT plan, and held a 30-day public notice and comment period, which ended on May 25, 2025 (see https://doee.dc.gov/node/1769906). DOEE has not fully evaluated the comments received in response to that action, the resolution of which may be considered in the resolution of this permitting action as well.

Emissions Estimates:

The maximum potential to emit air pollutants from Boiler 3, under the fuel usage limitations contained in the draft permit, has been estimated to be as follows:

	Maximum Annual Emissions
Pollutant	(tons/yr)
Particulate Matter (PM Total)	4.06
Sulfur Dioxide (SO2)	0.30
Nitrogen Oxides (NOx)	53.46
Volatile Organic Compounds (VOC)	2.06
Carbon Monoxide (CO)	31.45

Emission Limitations:

The proposed emission limits for the equipment are as follows (from Condition II of the draft permit):

a.   Emissions from Boiler 3 shall not exceed the following emission rates [20 DCMR 201]:

Pollutant	Emissions Burning Natural Gas (lb/hr)	Emissions Burning No. 2 Fuel Oil (lb/hr)
Oxides of Nitrogen (NOx)	40.60	40.60
Carbon Monoxide (CO)	16.72	7.25
Volatile Organic Compounds (VOC)	1.09	0.29
Sulfur Dioxide (SO2)	0.12	107.08
Total Particulate Matter [PM Total]*	1.51	4.79
Particulate Matter less than 10 microns (PM10)*	1.51	3.34
Particulate Matter less than 2.5 microns (PM2.5)*	1.51	2.25

* Includes both condensable and filterable particulate matter fractions.

b.   NO_x emissions shall not exceed 0.14 lb per million BTU when burning natural gas and No. 2 fuel oil in Boiler 3, or any combination of Boilers 3 through 7, as determined on a 30-day rolling average basis. This limit shall apply at all times including periods of startup, shutdown, or malfunction of the boiler. [20 DCMR 805.2 and 40 CFR 60.44b(a), (i), and (h)]

Note that this is a streamlined permit condition. This limit adopts an alternative RACT standard pursuant to 20 DCMR 805.2 and will be submitted to EPA for inclusion in the District’s State Implementation Plan (SIP) at 40 CFR 52, Subpart J. Compliance with this streamlined condition will ensure compliance with both standards.

c.   NO_x emissions shall not exceed either of the following [20 DCMR 804 and 20 DCMR 805.2]:

1.   0.2 lb/MMBTU, maximum 2-hour average, expressed as NO₂; or

2.   0.20 lb/MMBTU, based on a calendar day average.

Note that this is a streamlined permit condition. This limit adopts an alternative RACT standard pursuant to 20 DCMR 805.2 and will be submitted to EPA for inclusion in the District’s State Implementation Plan (SIP) at 40 CFR 52, Subpart J. Compliance with this streamlined condition will ensure compliance with both standards.

d.   Except as specified below, visible emissions whose opacity is in excess of ten percent (10%) (unaveraged), at any time shall not be permitted into the outdoor atmosphere. This visible emissions standard shall apply at all times, except that discharges shall be permitted for two (2) minutes during any startup, cleaning, adjustment of combustion or operational controls, or regeneration of emission control equipment; provided that such discharges shall not exceed the following opacities (unaveraged): [20 DCMR 606.1 and 606.2]

1. 1. 1. When burning exclusively natural gas, twenty percent (20%); and
2. 1. 2. When burning fuel oil or a combination of fuel oil and natural gas, twenty-seven percent (27%).

e.   Total suspended particulate matter emissions from Boiler 3 shall not be greater than 0.05 pounds per million BTU. [20 DCMR 600.1]

f.    An emission into the atmosphere of odorous or other air pollutants from any source in any quantity and of any characteristic, and duration which is, or is likely to be injurious to the public health or welfare, or which interferes with the reasonable enjoyment of life or property is prohibited. [20 DCMR 903.1]

Violation of the requirements of this condition that occur as a result of unavoidable malfunction, despite the conscientious employment of control practices, shall be an affirmative defense for which the owner or operator shall bear the burden of proof. 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. [20 DCMR 903.13(b)]

Note: This condition is District enforceable only.

g.   In addition to complying with the requirements of this permit document, the Permittee shall comply with all Plantwide Applicability Limits (PALs) established for the facility.

Additional Alternative NOx RACT Limit

In addition to Conditions II(b) and (c) listed above, the following Condition III(b) of the draft permit is proposed for inclusion in the District’s SIP at 40 CFR 52, Subpart J:

1. 2. The consumption of fuel, on a 12-consecutive-month rolling sum basis, shall be limited to the following [20 DCMR 201 and 20 DCMR 805.2]:
2. 1. 1. 1,069,730 gallons of No. 2 fuel oil (or other distillate oil as described in Condition III(a);
3. 1. 2. 748.80 MMSCF of natural gas; and
4. 1. 3. A total, combined heat input of all fuels of 763,776 MMBTU.

Note that this condition has been adopted as an alternative RACT standard pursuant to 20 DCMR 805.2 and will be submitted to EPA for inclusion in the District’s State Implementation Plan (SIP) at 40 CFR 52, Subpart J.

The permit applications and supporting documentation, along with the draft permit are available for public inspection at AQD and copies may be made available between the hours of 9:00 A.M. and 5:00 P.M. Monday through Friday. Interested parties wishing to view these documents should provide their names, addresses, telephone numbers and affiliation, if any, to Stephen S. Ours at (202) 498-8143 or [email protected]. Copies of the draft permit and related technical support memorandum are also available in the attachments section below.

Interested persons may submit written comments or may request a hearing on this subject within 30 days of publication of this notice. The written comments must also include the person’s name, telephone number, affiliation, if any, mailing address and a statement outlining the air quality issues in dispute and any facts underscoring those air quality issues. All relevant comments will be considered before taking final action on the permit application.

Comments on the proposed permit and any request for a public hearing should be addressed to:
 

Stephen S. Ours   
Chief, Permitting Branch - Air Quality Division

Department of Energy and Environment
1200 First Street NE, 5th Floor
Washington DC 20002

[email protected]

No comments or hearing requests submitted after July 7, 2025 will be accepted.

For more information, please contact Stephen S. Ours at (202) 498-8143.