AQ_F_1800073_20150625_CEM_GenCorr

WDENR
North Carolina Department of Environment and Natural Resources
Pat McCrory Donald R. van der Vaart
Governor Secretary
June 25, 2015
Mr. Rick R. Roper
General Manager III
Power Generation Carolina East
Marshall Steam Station
8329 East NC Hwy 150
Terrell,North Carolina 28682
SUBJECT: Approval of Petition to Revise PMCEMS Alternative Monitoring Option on SIP
Units 1 through 4
Duke Energy Carolinas, LLC—Marshall Steam Station
Terrell, Catawba County, North Carolina
Air Quality Permit No. 03676T52
Facility I.D. No. 1800073
Dear Mr. Roper:
This is in response to your letter of February 16, 2015,to Michael Pjetraj, Division of Air
Quality(DAQ), requesting a revision to the subject petition approval. In our original approval,
dated September 4, 2014, the DAQ granted Duke Energy Carolinas' (DEC)petition to use
particulate matter(PM) continuous emission monitoring systems (CEMS) in lieu of continuous
opacity monitoring systems (COMS) on Marshall Steam Station Units 1- 4. Emissions from
Units 1 and 2 are exhausted through common stack (CS) 01. Emissions from Units 3 and 4 are
exhausted through separate dedicated stacks. Since the PM and opacity standards for the four
utility boilers were only subject to North Carolina's State Implementation Plan(SIP), DEC
originally proposed a regulatory framework based upon the New Source Performance Standards
(NSPS)of 40 CFR Part 60, Subpart Da. DAQ approved the alternative monitoring request with
the understanding that DEC would revise the SIP unit petition as the compliance date approached
for meeting the Mercury and Air Toxics Standards (MATS)of 40 CFR Part 63, Subpart UUUUU
—National Emission Standards for Hazardous Air Pollutants: Coal-and Oil-Fired Electric
Utility Steam Generating Unit. Subsequent to our original approval, the PM CEMS installed at
Units 1-4 were certified and the permit application to incorporate the use of the PM CEMS was
submitted and is currently pending. Since Marshall Units 1-4 are now subject to MATS
UUUUU,DEC seeks to revise its petition and use MATS UUUUU as its regulatory framework
for alternative monitoring for PM and opacity standards under the North Carolina SIP.
In consideration of the above, DAQ has reviewed your revised petition, and in
conjunction with our authority under 15A NCAC 2D .0536 (b), 2D .0612, 2D .0606(g), 2D
.0614, and 40 CFR 75.14(b), we hereby approve your revised petition for MATS UUUUU to
serve as the regulatory framework for complying with 15A NCAC 2D .0536, 2D .0521, and 2D
.0606.
1641 Mail Service Center,Raleigh,North Carolina 27699-1641
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Mr. Rick R. Roper
June 25, 2015
Page 2
This latest approval for Marshall Steam Station Units 1- 4, supersedes our original approval of
September 4, 2014, and authorizes DEC to:
1. Use the PM CEMS, which met the certification requirements of 40 CFR Part 60, Appendix
B, Performance Specification 11 (PS-11), as an alternative to opacity monitoring provided
they also operate in accordance with the quality assurance plan(QAP) established under 40
CFR Part 60, Appendix F, Procedure 2. We agree that the PM CEMS monitoring option
provides a more accurate and representative measurement of the amount of PM emissions
exiting the stacks and entering the atmosphere than the COMS, which are located prior to the
control device. We also agree the PM CEMS are better suited for a saturated environment
whereas the COMS are not.
2. Use a PM CEMS with an alternate method of calculation to comply with the 20% annual
average opacity (AAO) limits of 15A NCAC 2D.0536 -Particulate Emissions from Electric
Utility Boilers by using either non-overlapping one-hour average PM CEMS measurements
in the wet stacks or COMS measurements upstream of the wet scrubbers. DEC has
correlated Method 9 opacity readings to milligrams per actual cubic meter(mg/acm) as
recorded by the PM CEMS during Marshall's initial PS-I I certification testing. By
establishing the equivalent PM concentration at the AAO limits, subsequent hourly PM
CEMS readings (mg/acm) can now be converted to hourly opacity averages. For the initial
year, AAO compliance will be determined using the formula that combines data from the PM
CEMS and COMS. The mathematical formula and methodology stated in "Belews Creek
Permit T29 Condition 2.1A.5 template"must be submitted and incorporated into Marshall's
permit. DAQ has concluded the alternate method will not cause a systematic or unacceptable
difference from the current method. It is mutually agreed that any values calculated using the
alternate method can be used for enforcement purposes of the AAO standards. DEC may
submit quarterly AAO reports rather than monthly reports. The alternative monitoring
request is approved pursuant to 2D .0536(b).
3. Use a PM CEMS to comply with the PM limits in 15 NCAC 2D .0536. In addition,we
approve DEC's proposal to reduce the PM limit from 0.1 lb/mmBTU (24-hour daily
arithmetic average based on the current language of NSPS Da)to the 0.03 lb/mmBTU (30-
boiler operating day rolling average) PM limit of MATS UUUUU. Boiler operating day, as
stated in MATS UUUUU, means"a 24-hour period that begins at midnight and ends the
following midnight during which any fuel is combusted at any time in the EGU, excluding
startup periods or shutdown periods. It is not necessary for the fuel to be combusted the
entire 24-hour period." We accept the supplemental data provided upon request via email on
March 11, 2015, and April 12, 2015, in order to verify that the 24-hour short term limit is not
threatened by a 30-boiler operating day longer term limit. The alternative monitoring request
is approved pursuant to 2D .0536(b).
4. Exempt stack gas opacity monitoring as provided under 40 CFR 75.14(b) - Specific
provisions for monitoring opacity - Unit with wet flue gas pollution control system. We
concur with the saturation calculations and data which demonstrated that condensed water is
present in the exhaust flue gas streams and would impede the accuracy of opacity
measurements.

Mr. Rick R. Roper
June 25, 2015
Page 3
5. Use a PM CEMS as an alternative to opacity monitoring for the 40% opacity limit in
paragraph (c) of 15A NCAC 21) .0521 - Control of Visible Emissions. The alternative
monitoring request is approved pursuant to 15A NCAC 21) .0612 -Alternative Monitoring
and Reporting Procedures. Consistent with MATS UUUUU, no periodic Method 9 visible
emission readings are required. DEC may continue to use either Method 9 observations or
COMS data to demonstrate compliance with opacity limit during required testing with mid
and high dust loads; however, DEC must submit these observations or COMS data and code
any excess opacity readings as monitor downtime and include the duration in monitor
downtime calculations.
6. Use a PM CEMS as an alternative to opacity monitoring for the 40% opacity limit in
paragraph(g) of 15A NCAC 2D .0606-Sources Covered by Appendix P of 40 CFR Part 51.
In order to demonstrate that good operation and maintenance (O&M) is being practiced for
minimizing emissions, DEC will use the methodology and content accepted in DAQ's
petition approval of June 26, 2014, for Belews Creek Units 1 & 2 for reporting PM CEMS
data from DEC SIP units. As stated in the petition, this approach will "[r]etain the same PM
CEMS monitoring/recordkeeping/and reporting approved in Belews Creek template permit
01983T29 (Condition 2.1 7b. and d. ii) [adjusted for Marshall 1 through 4 certification test
results]." The referenced proposal must also be submitted and incorporated into Marshall's
permit. The alternative monitoring request is approved pursuant to 2D .0612 and 2D
.0606(g).
7. Use a PM CEMS to satisfy the requirement for 15 NCAC 2D .0614 - Compliance Assurance
Monitoring(CAM) in accordance with 40 CFR 64.2(b)(vi) since the PM CEMS provides a
direct measurement of particulate in units of the emission standard. Should DEC retain the
COMS units to satisfy the CAM requirements under 21) .0614,please ensure all quality
assurance(QA)/quality control (QC)practices and criteria are followed as stated in the
current permit.
If you should have any questions,please call me at(919) 707-8719 or Dennis Igboko at
[phone] or [e-mail].
Sincerely,
�i
k/Lee A. aniel, Chief
Technical Services Section
Division of Air Quality,NCDENR
cc: Bill Horton—Duke Energy Carolinas Ron Slack—MRO
Cynthia Winston—Duke Energy Carolinas Central Files—Catawba County
Randy Wooten—Duke Energy Carolinas IBEAM Documents— 1800073
Michael Pjetraj —DAQ Central Office
Ed Martin—DAQ Central Office