DAQ-2025-001515

1

DAQC-268-25
Site ID 10892 (B5)

MEMORANDUM

TO: CEM FILE – CITY OF ST. GEORGE

THROUGH: Harold Burge, Major Source Compliance Section Manager

FROM: Rob Leishman, Environmental Scientist

DATE: March 10, 2025

SUBJECT: Source: Millcreek Generating Station Turbine #2 (MC-2)
Contact: Melissa Armer (Trinity Consultants, Inc) - 280-870-3215
Brad Burner – 435-627-4885
Location: Millcreek Station, 170 North 3232 East St. George, Washington
County, UT
Test Contractor: TRC Environmental
FRS ID#: UT0000004905300011
Permit/AO#: Title V operating permit 5300011005 dated April 29, 2019
Subject: Review of RA/PST Protocol dated February 24, 2025

On March 3, 2025, Utah Division of Air Quality (DAQ) received a protocol for a RA/PST (relative
accuracy/performance specification test) of the St. George City Power Millcreek MC-2 turbine in St.
George, Utah. Testing will be performed on April 17, 2025, to determine the relative accuracy of the O2,
NOX, and CO monitoring systems.

PROTOCOL CONDITIONS:

1. RM 3A used to determine dry molecular weight of the gas stream: OK
2. RM 7E used to determine NOX concentrations of emissions: OK
3. RM 10 used to determine CO concentrations of emissions: OK
4. RM 19 used to determine volumetric flow: OK
5. RM 205 used to validate gas dilution systems for field instrument calibration: OK

DEVIATIONS: No deviations were noted.

CONCLUSION: The protocol appears to be acceptable.

RECOMMENDATION: Send attached protocol review and test date confirmation notice.

1 8 2
st.
JVL
?nC
George
THE BRIGHTER SIDE
February 24,2025
Mr. Bryce Bird
Division Director
Attn: Rob Leishman
Utah Division of Air Quality
P.O. Box 144820
Salt Lake city, utah 84114-4820
RE: Notification of periodic RATA for ORIS Code: 56253, Unit/Stack ID: MC-2
In accordance with 40 CFR Part75.6l (a)(5) St. George City Power is submitting notification that
a continuous emissions monitoring system (CEMS) periodic relative accuracy test audit (RATA)
will be conducted on April l7 , 2025 . This test protocol is being submitted at least 21 days prior to the
test and in accordance with 40 CFR Part 7 5.61 (aX5).
If you have any questions or comments regarding this matter, please contact either myself or
Melissa Armer of Trinity Consultants, Inc. at [phone]. Thank you for your time and
attention to this matter.
Director
) 627-4840
cc:US EPA Clean Air Markets Division (CAMD)
US EPA Region 8
CITY OF ST. GEORGE
435-627-4000 I tzS E. 2OO N. - St. George,UT a477O I sgcity.org
}TRC
CONTINUOUS EMISSIONS MONITORING SYSTEM RELATIVE
ACCURACY TEST AUDIT (RATA) PROTOGOL
Turbine No.2 (MC-2)
Prepared For
St. George City Power
St. George, Utah
At
Millcreek Generating Station
170 N. 3232E.
St. George, Utah 84790
TRC Environmental Protocol 655318-MC2
February 20,2025
Submitted By
Marco Somoano
Project Manager
[phone]
[e-mail]
TRC Environmental
171 1 Newport Circle
Santa Ana, CA 92705 T 714-713-6530
USA
TRC Protocol 655318-MC2 2of11
}TRC
TABLE OF CONTENTS
1.0 |NTRODUCT|ON...... ...,...........3
1.1 Project Contact lnformation ...........3
2.0 SPECIFTC TEST PROCEDURES............... .....................4
3.0 ADDITIONAL REQUIRED TESTS ............,.4
3.1 Bias Test and Adjustment Factor ......................4
4.0 TEST PROGRAM SCHEDULE ...................5
5.0 PROJECT PERSONNE1................ .............5
6.0 PLANT REQU|REMENTS............. ..............5
7.0 TEST PROCEDURES............... ..................5
7.1 Oxygen (Oz) Determination ...........5
7.2 Nitrogen Oxides (NO,) Determination ...............6
7.3 Carbon Monoxide (CO)Determination......... .........................6
7.4 Gaseous Sampling P1an............ ........................6
8.0 QUALITY ASSURANCE PROCEDURES............. ...........6
APPENDED:
Traverse Point Layout
Documentation of EPA Approval for Divider Use
TRC Protocol 655318-MC2 3of11
}TRC
1.0 INTRODUCTION
TRC Environmental Corporation (TRC Environmental), will perform a continuous emissions
monitoring system (CEMS) relative accuracy test audit (RATA) to evaluate monitored levels of
nitrogen oxides (NO,), oxygen (Oz) and carbon monoxide (CO) from Turbine No. 2 (MC-2) at the
Millcreek Generating Station in St. George, Utah. The RATA will be completed in accordance with
Performance Specifications 2, 3 and 4A, Title 40, Code of Federal Regulations, Part 60 (40CFR60)
and Part 75 (40CFR75) at the source sampling locations.
The Millcreek Generating Station has two GE LM 6000 naturalgas turbines (MC-1 and MC-2).
1.1 Project Contact lnformation
Location Address Contact
Source Millcreek Generating Station
170 N.3232E.
St. George, Utah 84790
Brad Burner
Generation Superintendent
St. George City Power
170 N.3232E.
St. George, UT 84790
[phone] (phone)
[e-mail]
Testing Company TRC Environmental
1711 Newport Circle
Santa Ana, CA 92705
Marco Somoano
Project Manager
[phone] (cell)
[e-mail]
TRC Protocol 655318-MC2 4of11
}TRC
2.0 SPECIFIC TEST PROCEDURES
Test procedures are presented in Table 1, Test Matrix
Table 1: Test Matrix for MC-2
Please also note the following:
1. Nitrogen Oxides (NO-), carbon monoxide (CO), and oxygen (Oz) will be measured in
accordance with United States Environmental Protection Agency (USEPA) Title 40, Code of
Federal Regulations, Part 60 (40CFR60) Methods 7E, 10 and 3A.2. Lb/mmBtu calculations will be calculated in accordance with 40CFR75 Appendix A and EPA
Method 19 using the Fd-factor for natural gas of 8710 dscf/mmBtu.3. Lb/hr calculations will utilize published heat input values for natural gas to determine
volumetric flow rate in accordance with EPA Method 19 (using Fd of 8710 dscf/mmBtu and
HHV of 1050 scf/Btu). lf the facility has an HHV data feed, this data may also be used.4. A stratification test performed on April 30, 2012 by Air Pollution Testing, lnc. at steady state
and normal load conditions showed NOx stratification above 10%. As such, RATA samples
will be collected by traversing the stack using the three long points published in 40CFR60,
App. B, P.S. 2 (16.7o/o, 50% and 83.3% of diameter).5. The RATA testing will be performed at normal load (which can be termed as high or base
load) and is based on the unit's operating history as long as normal load is above 50%.6. Expected concentrations: NO,, 1.0 to 2.0 ppmv, CO 0.4 to 1.5 ppmv, Oz 15.60/o.7. CEMS data will be recorded on a data acquisition system (one-minute averages during runs;
1 S-second averages during calibrations).8. Reports will be submitted to the District within 30 days of test completion and will include all
required documentation.
3.0 ADDITIONAL REQUIRED TESTS
3.1 Bias Test and Adjustment Factor
The relative accuracy test data sets will be evaluated to determine the bias of each NO, continuous
emissions monitoring system in accordance with the procedures of Section 7.6, 40CFR75, Appendix
A.
TRC Protocol 65531 8-MC2 5ofl1
Procedure Pa ra meter Units Perf. Spec.
Ref.
(40CFR60 or
40cFR7s )
:PA Method
(40cFR60,
App.A)
No. of
Test
Runs;
Run
Length
Performa nce Speci fi cati on
(Semia nnua l;Annua l)
Sta nda rd
RATA,
4OCFR75
o2 o/o 75, App. A 3A 9;27
min.
Parl7s,70% or d+/- Lo/o;7.5o/o or d+f -
o.7%
n/a
RATA,
40CFR75
NOx lblmmBtu 75, App. A 7Elt9 9;27
min.
Part75,70%orif RM s0.2 lb/mmBtu
d+/- 0.02 lb/mmBtu; 7 .5o/o or if RM <0.2
I b/mmBtu d+/- 0.0151 b/mmBtu
n/a
RATA,
40cFR60
co ppmv
@75o/o02
60, App. B,
P.S.44
10/3A 9;27
min.
Part 60, n/a;L0% of RM or 5% of std or
+/-5 ppmv
6
RATA,
4OCFRSO
co I b/hr 60, App. B,
P.S.6
tol79 9;21
min.
Part 60, n/a;2Oo/o of RM or 10% of std s.21
+TrRc
4.0 TEST PROGRAM SCHEDULE
The following is the current schedule.
2025
Day, Date Activity
On€ite
Hours
Thur, Apr 17 MC-2: Perform CEMS RATA.10
5.0 PROJECT PERSONNEL
1 Project Manager1 Field Engineer
6.0 PLANT REQUIREMENTS
TRC Environmental must be supplied with the following items in order to complete this test program:
1. Safe access to test locations.2. Electrical power 1 10 V, 30 A, 60 cycle service at the test locations.3. Four-inch test ports cleaned and loose prior to arrival of test crew.4. Any scaffolding or manlift required to reach the test locations.5. Sufficient lighting at the test locations.6. Plant or pollution control equipment operating data for report.7. Steady load during test period.8. Parking location to place TRC Environmental mobile trailer within 200 feet of sampling
locations with access to 480 V power.9. Fuel samples, if required (analysis cost not included).10. Radio/telephone communication between the test location and the controlroom.11. All data and summaries required to complete the RATA report including but not limited to
operating data during that period, calibration data, equipment descriptions required for the
report (TRC Environmental must be supplied all data prior to crew leaving site).
7.0 TEST PROCEDURES
All testing, sampling, analytical, and calibration procedures used for this test program will beperformed as described in the Code of Federal Regulations, Title 40, Part 60, Appendix A
(40CFR60), Methods 3A,7E, 10 and 19 and the latest revisions thereof. Where applicable, the
Quality Assurance Handbook for Air Pollution Measurement Sysfems, Volume lll, Stationary Source
Specific Methods, USEPA 60014-77-027b is used to determine the precise procedures.
7.1 Oxygen (Oz) Determination
An oxygen (Oz) analyzer is used to determine 02 concentrations in the stack gas in accordance with
Method 34, 40CFR60. This instrument has a paramagnetic-based detector. Three-point calibration error
checks are performed before and after each run series using Protocol One gases for high- and mid-range
checks and ultra-pure nitrogen for the zero check. Two-point calibration bias/drift checks are performed
before and after each run series, using zero gas and the upscale gas closest to the effiuent
TRC Protocol 65531 8-MC2 6of11
}TRC
concentration. A gas divider (dilution system) certified in accordanee with EPA Method 205 may be used
to generate calibration concentrations (see EPA approval documentation at the end of protocol).
7.2 Nitrogen Oxides (NO,) Determination
Methods 7E, 40CFR60, is used for determining nitrogen oxides (NO,) emissions from the test
location. A gas sample is continuously extracted from the gas stream through a heated probe and
gas conditioning system to remove the moisture. A portion of the sample stream is conveyed via a
sampling line to gas analyzers for determination of NO*. The NO, analyzer uses a
chemiluminescence's-based detector. Three-point calibration error checks are performed before and
after each run series using Protocol One gases for high- and mid-range checks and ultra-pure nitrogen
for the zero check. Two-point calibration bias/drift checks are performed before and after each run
series, using zero gas and the upscale gas closest to the effluent concentration. A gas divider (dilution
system) certified in accordance with EPA Method 205 may be used to generate calibration
concentrations (see EPA approval documentation at the end of protocol). A NO* converter efficiency
check will be conducted using 15-'t8 ppmv NO2 gas.
7.3 Carbon Monoxide (CO) Determination
The Method 10,40CFR60 test procedure is used to determine the carbon monoxide (CO)
concentrations. A continuous gas sample is extracted from the gas and analyzed for CO content
using a nondispersive infrared (NDIR) analyzer. The gas stream is conditioned by condensing
moisture and filtering particulate prior to the analyzer. This instrument employs an internal gas
correlation filter wheel that eliminates potential detector interference. lnstruments so equipped do not
require the use of an interference removal trap.
Three-point calibration error checks are performed before and after each run series using Protocol One
gases for high- and mid-range checks and ultra-pure nitrogen for the zero check. Two-point calibration
bias/drift checks are performed before and after each run series, using zero gas and the upscale gas
closest to the effluent concentration. A gas divider (dilution system) certified in accordance with EPA
Method 205 may be used to generate calibration concentrations (see EPA approval documentation at the
end of protocol).
7.4 Gaseous Sampling Plan
TRC Environmental will complete a minimum of nine 21-minute tests by traversing the stack each run
using the three long points of 40 CFR 60, App. B, P.S. 2 of 16.7, 50.0 and 83.3 percent of stack
diameter. The system will be calibrated as described above. Following each calibration, a stable on-
line response will be regained prior the start of the next run. Data will be collected by a data logger.
The actual time of each test will be compared to the output of the monitor taking into consideration
response times determined on both the TRC Environmental and plant CEM system. The
determination of relative accuracy will be calculated based on the emissions as reported by each
system corrected on the same basis.
8.0 QUALITY ASSURANCE PROCEDURES
TRC Environmental recognizes the previously described reference methods to be very technique-
oriented and attempts to minimize all factors that can increase error by implementing its Quality
Assurance Program into every segment of its testing activities.
Shelf life of chemical reagents prepared at the TRC Environmental laboratory or at the jobsite does
not exceed those specified in the above-mentioned methods. ln addition, those reagents having a
TRC Protocol 65531 8-MC2 7of11
}TRC
shelf life of one week are prepared daily at the jobsite. When on-site analyses are required, the same
person performing the analysis performs all reagent standardization daily.
Dry and wet test meters are calibrated according to methods described in lhe Quality Assurance
Handbook for Air Pollution Measurement Sysfems, Sections 3.3.2, 3.4.2 and 3.5.2. Percent error for
the wet test meter according to the methods is less than the allowable error of 1.0%. The dry test
meters measure the test sample volumes to within 2o/o at the flow rate and conditions encountered
during sampling. Calibration gases are EPA Protocolgases.
Raw data is kept on file at the TRC Environmental offices in Costa Mesa, CA. All samples from the
test program will be retained for 60 days after the submittal of the report, after which they will be
discarded unless TRC Environmental is advised otherwise.
Calculations are performed by computer. An explanation of the nomenclature and calculations along
with the complete test results will be appended. Also to be appended are calibration data sheets and
copies of the raw field data sheets.
TRC Protocol 65531 8-MC2 8 of 1'l
}TRC
Traverse Point Layout
Stack EIa.: 13.0 ft. 0.0 in.
Stack Da.: 156.00 in.
turt Length: 6.0 in.
Wall Thickner 3.5 in.
Traverse R. % Stack Elia
hrt tfunber
Stack Dstance
(in.)
26 1
78.0
129.9
4
fort Dstance
1
2
3
16.7
50.0
83.3
(in.)
35.6
87.5
139.4
3fr.0in.
TRC Protocol 655318-MC2 9of11
Conroy, Neal
From:
Sent:
To:
Cc:
Subject
Patefield, Scott < [e-mail]>
Monday, March 24,2074 9:12 AM
Melissa L. Armer
Conroy, Neal; Rod Carter; Phillip Solomon
RE:St. George City Power- Millcreek MC-2 RATA
This is an EXTERNAL email. STOP. THINK before you CLICK links or OPEN attachments.
Melissa,
Thanks for that information. Using a dilution system following method 205 will be acceptable for the St. George City
Power RATA on the MC-2 unit scheduled to be conducted on April L8,2Ot4.
Please feel free to contact me with any additional questions or comments.
Thanks,
Scott
scott Patefield
Air and Toxics Enforcement
U.S. EPA, Region 8 (8ENF-AT)
1595 Wynkoop Street
Denver, CO 80202-1129
303-3L2-6248 (office)
patefield.scott@e pa.sov
Flom: Melissa L. Armer [mailto :[e-mail]]
Sent: Monday, March 24,2014 10:08AM
To: Patefield, Scott
Cc: Conroy, Neal; Rod Carter; Phillip Solomon
Subject: RE: St. George City Power- Millcreek MC-2 RATA
Scott,
I confirmed with the test company and the divider is a dilution system that is certified according to Method 205. The
divider is tested on-site the day of the test to confirm the method requirements.
Let me know if you need additional information.
Melissa
Melissa Armer, P.E.
JBR Environmental Consultants, !nc.
7669 West Riverside Drive, Suite 101
Boise, ID 83714
lpl 208.853.0883
lm)208.272.0446
www.ibrenv.com
TRC Protocol 65531 8-MC2 10of11
From: Patefleld, Scott [mailto:[e-mail]]
Sent: Monday, March 24,2014 9:26 AM
To: Melissa L. Armer
Cc Conroy, Neal; Rod Carter; Phillip Solomon
Subject: RE: St. George City Power- Millcreek MC-z RATA
Melissa,
Could you give me more information regarding the divider? l'm not sure l'm familiar with this.
using a dilution system would be acceptable, not sure if this is what is meant by the divider...
Thanks,
Scott
scott Patefield
Air and Toxics Enforcement
U.S. EPA, Region 8 (8ENF-AT)
L595 Wynkoop Street
Denver, CO 802O2-L129
3A34L2-6248 (office)
patefield.scott @e pa.eov
The use of method 205
From: Melissa L. Armer tmaitto:marmerQbrc l
Sent: Thursday, March t3,20t4 B:33 PM
To: Patefield, Scott
Cc Conroy, Neal; Rod Carter; Phillip Solomon
Subject: St. George City Power- Millcreek MC-2 RATA
Scott,
Per our discussion earlier this week and your voice message from 3lL3l74 below is a summary of our request. St.
George City Power will be conducting a RATA on their MC-2 unit on April 78,2074. The testing company, TRC Solutions
is requesting the use of NOx and CO test gasses with a range of 0-10 ppm. At the estimated emission rates for the MC-2
unit NOx would be at 18% and CO at 8% of the test gas range. The method requires "To the extent practicable. select a
high-level gas concentration that will resutt in the measured emissions being between 20 and 100 percent of the
calibration span". St. George is requesting approval of a minor modification for this test protocol as it is not practicable
for the test company to acquire a lower range test gas. As an alternative, TRC Solutions would be able to meet the
acceptable ranges identified in the test method by using a divider if approved.
I will be out of the office Friday March 14th returning March 17th.Thank you for your time and consideration.
Melissa
Melissa Armer, P.E.
JBR Environmental Gonsultants, lnc.
7669 West Riverside Drive, Suite 101
Boise, lD 83714
[p] 208.853.0883
1m1208.272.0446
www.ibrenv.com
i ri j,.'\l it
I
l
TRC Protocol 6553'1 8-MC2 '1 '1 of 11