DAQ-2025-000972

1
DAQC-CI160850001-25
Site ID 16085 (B1)

MEMORANDUM

TO: FILE – DESERET POWER ELECTRIC COOPERATIVE – Solomon Generating
Station

THROUGH: Chad Gilgen, Minor Source Compliance Section Manager

FROM: Daniel Riddle, Environmental Scientist

DATE: February 3, 2025

SUBJECT: FULL COMPLIANCE EVALUATION, Minor, Washington County

INSPECTION DATE: January 21, 2025

SOURCE LOCATION: 4570 South River Road
St. George, UT 84790

DIRECTIONS: Remotely-controlled site. Contact prior to inspection to have
someone meet you at the source location.

SOURCE CONTACTS: Tyler Esplin, Environmental Superintendent
435-781-5706, [e-mail]

OPERATING STATUS: Operating normally at the time of inspection.

PROCESS DESCRIPTION: The Solomon Generating Station is a power station located in St.
George that operates to help meet peak demands for energy
during the summer months, as well as operating as a back-up
power source to the Ft. Pierce Industrial Park customers in the
event of an outage. The source consists of six (6) G3520H
Caterpillar engines rated at 3,457 brake horsepower. Each
generator operates up to 4,000 hours per year.

APPLICABLE REGULATIONS: Approval Order (AO) DAQE-AN160850001-22, dated
April 18, 2022

NSPS (Part 60) JJJJ: Standards of Performance for Stationary
Spark Ignition Internal Combustion Engines,
MACT (Part 63) ZZZZ: National Emissions Standards for
Hazardous Air Pollutants for Stationary Reciprocating Internal
Combustion Engines

) $ ' $ '
2
SOURCE EVALUATION:

Name of Permittee: Permitted Location:

Deseret Power Electric Cooperative
Solomon Generating Station

10714 South Jordan Gateway 4570 South River Road
South Jordan, UT 84095 St. George, UT 84790

SIC Code: 4911: (Electric Services)

Section I: GENERAL PROVISIONS

I.1 All definitions, terms, abbreviations, and references used in this AO conform to those used in the
UAC R307 and 40 CFR. Unless noted otherwise, references cited in these AO conditions refer to
those rules. [R307-101]

I.2 The limits set forth in this AO shall not be exceeded without prior approval. [R307-401]

I.3 Modifications to the equipment or processes approved by this AO that could affect the emissions
covered by this AO must be reviewed and approved. [R307-401-1]

I.4 All records referenced in this AO or in other applicable rules, which are required to be kept by
the owner/operator, shall be made available to the Director or Director's representative upon
request, and the records shall include the two-year period prior to the date of the request. Unless
otherwise specified in this AO or in other applicable state and federal rules, records shall be kept
for a minimum of two (2) years. [R307-401-8]

I.5 At all times, including periods of startup, shutdown, and malfunction, owners and operators shall,
to the extent practicable, maintain and operate any equipment approved under this AO, including
associated air pollution control equipment, in a manner consistent with good air pollution control
practice for minimizing emissions. Determination of whether acceptable operating and
maintenance procedures are being used will be based on information available to the Director
which may include, but is not limited to, monitoring results, opacity observations, review of
operating and maintenance procedures, and inspection of the source. All maintenance performed
on equipment authorized by this AO shall be recorded. [R307-401-4]

I.6 The owner/operator shall comply with UAC R307-107. General Requirements: Breakdowns.
[R307-107]

I.7 The owner/operator shall comply with UAC R307-150 Series. Emission Inventories. [R307-150]

I.8 The owner/operator shall submit documentation of the status of construction or modification to
the Director within 18 months from the date of this AO. This AO may become invalid if
construction is not commenced within 18 months from the date of this AO or if construction is
discontinued for 18 months or more. To ensure proper credit when notifying the Director, send
the documentation to the Director, attn.: NSR Section. [R307-401-18]

Status: In Compliance. No limits set forth in this AO appear to have been exceeded. The
source stated that there have been no modifications to the equipment or processes. The
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equipment appeared to be properly operated and maintained according to manufacturer
recommendations. Records are kept as required and were made available after the
inspection. No breakdowns have been reported since the previous inspection. No emission
inventory is required at this source. The source submitted their initial notification on
September 28, 2023. See DAQC-CI160850001-23 for additional information.

Section II: SPECIAL PROVISIONS
II.A The approved installations shall consist of the following equipment: II.A.1 15 MW Ft. Pierce Powerplant
II.A.2 Six (6) Natural Gas Engines (G3520H Caterpillar)
Stationary Spark Ignition Internal Combustion Engines.
Type: 4-Stroke lean burn.
Rating: 3,457 bhp.
Control: selective catalytic reduction (SCR) and oxidation catalyst (OC)

Status: In Compliance. No unapproved equipment was observed at the time of
inspection.

II.B Requirements and Limitations

II.B.1 Operation Conditions

II.B.1.a The owner/operator shall not operate each natural gas-fired engine for more than 4,000 hours per rolling 12-month period. [R307-401-8]
II.B.1.a.1 The owner/operator shall:

A. Install a non-resettable hour meter on each engine to determine total hours of operation

B. Record hours of operation each day

C. Use the hours of operation to calculate a new rolling 12-month total by the 20th day of
each month using data from the previous 12 months

D. Keep hours of operation records for all periods the plant is in operation.

[R307-401-8]

Status: In Compliance. For the rolling 12-month period from January 2024 to September
2024, generator hours are as follows:

Generator 1: 1,588 hours
Generator 2: 1,241 hours
Generator 3: 898 hours
Generator 4: 1,984 hours
Generator 5: 998 hours
Generator 6: 1,765 hours
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A non-resettable meter is installed on each generator. Hours are recorded daily. Records
are stored digitally for all times the station is in operation. See the attachments section for
additional information.

II.B.1.b The owner/operator shall not allow visible emissions from the natural gas-fired engines to exceed
10% opacity. [R307-401-8]

II.B.1.b.1 Opacity observations of emissions from stationary sources shall be conducted in accordance with
40 CFR 60, Method 9. [R307-201-3]

Status: In Compliance. No visible emissions were observed at the time of inspection. See
the attached VEO form for additional information.

II.B.1.c The owner/operator shall install a stack on each generator engine that has a stack height of no
less than 45 feet as measured from the base of the stack. All engine exhaust shall pass through
the exhaust stack prior to atmospheric release. [R307-401-8]

Status: In Compliance. The height of each stack is at least 45 feet tall. All generators onsite
are routed through a stack. See the email correspondence for more information.

II.B.2 Stack Testing Condition

II.B.2.a The owner/operator shall not emit more than the following rates and concentrations from each of
the natural gas-fired engines:

Pollutant (g/bhp-hr) (lb/hr)

NOx 0.07 0.53
CO 0.105 0.80
VOC 0.163 1.24.

[R307-401-8]

Status: In Compliance. According to DAQC-256-23, the emission limits and concentrations
for NOx, CO, and VOC are within acceptable ranges. See DAQC-256-23 for detailed
results. The summary table from stack testing is attached below as well.

II.B.2.a.1 Compliance Demonstration
To demonstrate compliance with the emission limitations above, the owner/operator shall
perform stack testing on the emissions unit according to the stack testing conditions contained in
this AO. [R307-165-2, R307-401-8]

Status: In Compliance. Source conducted their initial stack test on November 29 –
December 1, 2022. See DAQC-256-23 for additional information.

II.B.2.a.2 Initial Test
The owner/operator shall conduct an initial stack test on the emission unit within 180 days after
startup of the emission unit. [R307-165-2]

Status: In Compliance. Source conducted stack test within 180 days of startup of the
generators.
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II.B.2.a.3 Test Frequency
The owner/operator shall conduct a stack test on the emission unit within three (3) years after the
date of the most recent stack test of the emission unit. The Director may require the
owner/operator to perform a stack test at any time. [R307-401-8]

Status: In Compliance. Stack test was conducted on November 29 – December 1, 2022. The
source was reminded to complete new stack testing by November 29, 2025. See the
attached email correspondence.

II.B.2.a.4 Notification
At least 30 days prior to conducting a stack test, the owner/operator shall submit a source test
protocol to the Director. The source test protocol shall include the items contained in
R307-165-3. If directed by the Director, the owner/operator shall attend a pretest conference.
[R307-165-3, R307-401-8]

Status: In Compliance. Source sent notification within 30 days of conducting stack test. See
DAQC-256-23 for additional information.

II.B.2.a.5 Testing & Test Conditions
The owner/operator shall conduct testing according to the approved source test protocol and
according to the test conditions contained in R307-165-4. [R307-165-4, R307-401-8]

Status: In Compliance. Testing protocol was approved and accepted by the DAQ. See
DAQC-256-23 for additional information.

II.B.2.a.6 Access
The owner/operator shall provide Occupational Safety and Health Administration (OSHA)- or
Mine Safety and Health Administration (MSHA)-approved access to the test location.
[R307-401-8]

Status: In Compliance. The test location is safely accessible.

II.B.2.a.7 Reporting
No later than 60 days after completing a stack test, the owner/operator shall submit a written
report of the results from the stack testing to the Director. The report shall include validated
results and supporting information. [R307-165-5, R307-401-8]

Status: In Compliance. Results were sent to the DAQ within 60 days of the date the stack
test was conducted. See DAQC-256-23 for additional information.

II.B.2.a.8 Possible Rejection of Test Results
The Director may reject stack testing results if the test did not follow the approved source test
protocol or for a reason specified in R307-165-6. [R307-165-6, R307-401-8]

II.B.2.b Test Methods
When performing stack testing, the owner/operator shall use the appropriate EPA-approved test
methods as acceptable to the Director. Acceptable test methods for pollutants are listed below.
[R307-401-8]

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II.B.2.b.1 Standard Conditions

A. Temperature - 68 degrees Fahrenheit (293 K)

B. Pressure - 29.92 in Hg (101.3 kPa)

C. Averaging Time - As specified in the applicable test method

[40 CFR 60 Subpart A, 40 CFR 63 Subpart A, R307-401-8]

II.B.2.b.2 NOx
40 CFR 60, Appendix A, Method 7; Method 7E; or other EPA-approved testing method as
acceptable to the Director. [R307-401-8]

II.B.2.b.3 VOC
40 CFR 60, Appendix A, Method 18; Method 25; Method 25A; 40 CFR 63, Appendix A,
Method 320; or other EPA-approved testing method as acceptable to the Director.
[R307-401-8]

II.B.2.b.4 CO
40 CFR 60, Appendix A, Method 10 or other EPA-approved testing method as acceptable to the
Director. [R307-401-8]

Status: In Compliance. Methods utilized to conduct the stack test were reviewed and
approved by the DAQ. See DAQC-256-23 for additional information.

Section III: APPLICABLE FEDERAL REQUIREMENTS

In addition to the requirements of this AO, all applicable provisions of the following federal programs
have been found to apply to this installation. This AO in no way releases the owner or operator from any
liability for compliance with all other applicable federal, state, and local regulations including
UAC R307.

NSPS (Part 60) JJJJ: Standards of Performance for Stationary Spark Ignition Internal Combustion Engines

Status: In Compliance. Compliance with this subpart is satisfied by installing a certified engine,
maintaining and operating the engines in accordance with the manufacturer's instructions, installation
of a non-resettable hour meter, and maintaining records of use. All information provided at the time of
inspection indicate these engines are being properly maintained and operated in accordance with this
subpart.

MACT (Part 63) ZZZZ: National Emissions Standards for Hazardous Air Pollutants for Stationary
Reciprocating Internal Combustion Engines

Status: In Compliance. The generators did not operate over their permitted hour usage rate of 4,000
per rolling 12-month period. The highest total for any generator during the timeframe was 1,765 hours.
The generators are maintained and operated according to manufacturer's specifications and are stack
tested every 3 years.

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AREA SOURCE RULES EVALUATION:

The following Area Source Rules were evaluated during this inspection:

Standards of Performance for New Stationary Sources [R307-210]

Status: Compliance with this area source rule is satisfied by compliance with Federal Requirement
NSPS (Part 60) Subpart JJJJ. See Section III above for more information.

National Emission Standards for Hazardous Air Pollutants [R307-214]

Status: In Compliance. Compliance with this area source rule is satisfied by compliance with Federal
Requirement MACT (Part 63) Subpart ZZZZ. See Section III above for more information.

EMISSION INVENTORY:
The emissions listed below are an estimate of the total potential emissions (PTE) from Deseret Power
Electric Cooperative – Solomon Generating Station on the Approval Order (AO) DAQE-AN160850001-
22, dated April 18, 2022. PTE are supplied for supplemental purposes only.

Criteria Pollutant PTE tons/yr
CO2 Equivalent 34697.00
Carbon Monoxide 9.60
Nitrogen Oxides 6.40
Particulate Matter - PM10 (Fugitives) 2.90
Particulate Matter - PM2.5 (Fugitives) 2.90
Sulfur Dioxide 0.17
Volatile Organic Compounds 14.90

Hazardous Air Pollutant PTE lbs/yr
Acetaldehyde (CAS #75070) 2420
Acrolein (CAS #107028) 1500
Formaldehyde (CAS #50000) 10600
Generic HAPs (CAS #GHAPS) 620
Methanol (CAS #67561) 220

PREVIOUS ENFORCEMENT
ACTIONS: No enforcement action within the past five years.

COMPLIANCE STATUS &
RECOMMENDATIONS: In regards to Approval Order (AO) DAQE-AN160850001-22,
dated April 18, 2022, the overall status is: In Compliance.
Facility is well maintained. Records were made available when
requested.

HPV STATUS: Not Applicable.

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RECOMMENDATION FOR
NEXT INSPECTION: Inspect at the usual interval. This is a remotely-controlled site.
Contact prior to inspection to have someone meet you at the
source location.

NSR RECOMMENDATIONS: None at this time.

ATTACHMENTS: Email correspondence, generator usage, stack test results
Solomon Solomon Solomon Solomon Solomon Solomon
Unit Unit Unit Unit Unit Unit
1 2 3 4 5 6
Date (hrs)(hrs)(hrs)(hrs)(hrs)(hrs)
1/1/2024 3531 3499 2999 3468 2740 3333
1/2/2024
1/3/2024
1/4/2024
1/5/2024
1/6/2024
1/7/2024
1/8/2024
1/9/2024
1/10/2024
1/11/2024
1/12/2024
1/13/2024
1/14/2024 3534 3500 3005 3472 2745 3337
1/15/2024
1/16/2024
1/17/2024
1/18/2024
1/19/2024
1/20/2024
1/21/2024
1/22/2024
1/23/2024
1/24/2024
1/25/2024
1/26/2024
1/27/2024
1/28/2024
1/29/2024
1/30/2024
1/31/2024
2/1/2024
2/2/2024
2/3/2024
2/4/2024
2/5/2024
2/6/2024
2/7/2024 3535 3502 3015 3476 2756 3346
2/8/2024
2/9/2024
2/10/2024
2/11/2024
2/12/2024 3535 3502 3015 3476 2756 3346
2/13/2024
2/14/2024
2/15/2024
2/16/2024
2/17/2024
2/18/2024
2/19/2024 3535 3502 3015 3476 2756 3346
2/20/2024
2/21/2024
2/22/2024
2/23/2024
2/24/2024
2/25/2024
2/26/2024 3535 3502 3016 3477 2758 3347
2/27/2024
2/28/2024
2/29/2024
3/1/2024
3/2/2024
3/3/2024 3535 3502 3018 3477 2760 3348
3/4/2024
3/5/2024
3/6/2024
3/7/2024
3/8/2024
3/9/2024
3/10/2024 3535 3503 3019 3478 2761 3349
3/11/2024
3/12/2024
3/13/2024
3/14/2024
3/15/2024
3/16/2024
3/17/2024
3/18/2024
3/19/2024
3/20/2024
3/21/2024
3/22/2024
3/23/2024
3/24/2024 3535 3503 3021 3479 2765 3351
3/25/2024
3/26/2024
3/27/2024
3/28/2024
3/29/2024
3/30/2024
3/31/2024 3535 3503 3023 3479 2768 3353
4/1/2024
4/2/2024
4/3/2024
4/4/2024
4/5/2024
4/6/2024
4/7/2024 3537 3504 3027 3481 2771 3355
4/8/2024
4/9/2024
4/10/2024
4/11/2024
4/12/2024
4/13/2024
4/14/2024 3537 3504 3028 3482 2772 3355
4/15/2024
4/16/2024 3537 3505 3031 3483 2777 3358
4/17/2024
4/18/2024
4/19/2024
4/20/2024
4/21/2024 3537 3505 3034 3484 2780 3360
4/22/2024
4/23/2024
4/24/2024
4/25/2024
4/26/2024
4/27/2024
4/28/2024 3537 3505 3037 3484 2784 3362
4/29/2024
4/30/2024
5/1/2024
5/2/2024
5/3/2024
5/4/2024
5/5/2024 3537 3506 3038 3485 2786 3363
5/6/2024
5/7/2024
5/8/2024
5/9/2024
5/10/2024
5/11/2024
5/12/2024 3537 3506 3038 3485 2786 3363
5/13/2024
5/14/2024
5/15/2024
5/16/2024
5/17/2024
5/18/2024
5/19/2024 3537 3506 3039 3485 2787 3363
5/20/2024
5/21/2024
5/22/2024
5/23/2024
5/24/2024
5/25/2024
5/26/2024
5/27/2024 3537 3506 3039 3486 2787 3363
5/28/2024
5/29/2024
5/30/2024
5/31/2024
6/1/2024
6/2/2024 3538 3508 3041 3489 2790 3367
6/3/2024
6/4/2024
6/5/2024
6/6/2024
6/7/2024
6/8/2024
6/9/2024 3538 3508 3046 3489 2796 3370
6/10/2024
6/11/2024
6/12/2024
6/13/2024
6/14/2024
6/15/2024
6/16/2024 3538 3508 3051 3491 2802 3375
6/17/2024
6/18/2024
6/19/2024
6/20/2024
6/21/2024
6/22/2024
6/23/2024 3538 3509 3051 3493 2804 3376
6/24/2024
6/25/2024
6/26/2024
6/27/2024
6/28/2024
6/29/2024
6/30/2024 3546 3511 3053 3501 2813 3384
7/1/2024
7/2/2024
7/3/2024
7/4/2024
7/5/2024
7/6/2024
7/7/2024 3708 3511 3109 3657 2846 3546
7/8/2024
7/9/2024
7/10/2024
7/11/2024
7/12/2024
7/13/2024
7/14/2024 3753 3511 3109 3826 2846 3714
7/15/2024
7/16/2024
7/17/2024
7/18/2024
7/19/2024
7/20/2024
7/21/2024 3927 3511 3109 3999 2846 3888
7/22/2024
7/23/2024
7/24/2024
7/25/2024
7/26/2024
7/27/2024
7/28/2024 4094 3511 3109 4167 2846 4055
7/29/2024
7/30/2024
7/31/2024
8/1/2024
8/2/2024
8/3/2024
8/4/2024 4257 3664 3109 4327 2846 4218
8/5/2024
8/6/2024
8/7/2024
8/8/2024
8/9/2024
8/10/2024
8/11/2024 4425 3832 3109 4495 2846 4386
8/12/2024
8/13/2024
8/14/2024
8/15/2024
8/16/2024
8/17/2024
8/18/2024
8/19/2024
8/20/2024
8/21/2024
8/22/2024
8/23/2024
8/24/2024
8/25/2024 4733 4088 3227 4803 3121 4533
8/26/2024
8/27/2024
8/28/2024
8/29/2024
8/30/2024
8/31/2024
9/1/2024
9/2/2024 4733 4274 3413 4989 3254 4628
9/3/2024
9/4/2024
9/5/2024
9/6/2024
9/7/2024
9/8/2024 4754 4361 3510 5085 3351 4725
9/9/2024
9/10/2024
9/11/2024
9/12/2024
9/13/2024
9/14/2024
9/15/2024 4864 4474 3623 5198 3464 4837
9/16/2024
9/17/2024
9/18/2024
9/19/2024
9/20/2024
9/21/2024
9/22/2024 4977 4584 3736 5311 3577 4950
9/23/2024
9/24/2024
9/25/2024
9/26/2024
9/27/2024
9/28/2024
9/29/2024 5090 4697 3849 5424 3690 5063
9/30/2024
10/1/2024
10/2/2024
10/3/2024
10/4/2024
10/5/2024
10/6/2024 5109 4716 3868 5442 3706 5083
10/7/2024
10/8/2024
10/9/2024
10/10/2024
10/11/2024
10/12/2024
10/13/2024 5112 4720 3872 5442 3706 5085
10/14/2024
10/15/2024
10/16/2024
10/17/2024
10/18/2024
10/19/2024
10/20/2024 5112 4722 3874 5445 3708 5086
10/21/2024
10/22/2024
10/23/2024
10/24/2024
10/25/2024
10/26/2024
10/27/2024 5113 4725 3878 5445 3711 5087
10/28/2024
10/29/2024
10/30/2024
10/31/2024
11/1/2024
11/2/2024
11/3/2024 5113 4725 3878 5445 3712 5087
11/4/2024
11/5/2024
11/6/2024
11/7/2024
11/8/2024
11/9/2024
11/10/2024 5114 4726 3879 5447 3712 5088
11/11/2024
11/12/2024
11/13/2024
11/14/2024
11/15/2024
11/16/2024
11/17/2024 5115 4729 3883 5447 3716 5091
11/18/2024
11/19/2024
11/20/2024
11/21/2024
11/22/2024
11/23/2024
11/24/2024 5116 4730 3886 5448 3723 5093
11/25/2024
11/26/2024
11/27/2024
11/28/2024
11/29/2024
11/30/2024
12/1/2024 5116 4731 3886 5448 3723 5093
12/2/2024
12/3/2024
12/4/2024
12/5/2024
12/6/2024
12/7/2024
12/8/2024 5119 4734 3890 5449 3726 5096
12/9/2024
12/10/2024
12/11/2024
12/12/2024
12/13/2024
12/14/2024
12/15/2024 5119 4737 3893 5449 3730 5096
12/16/2024
12/17/2024
12/18/2024
12/19/2024
12/20/2024
12/21/2024
12/22/2024 5119 4738 3894 5449 3731 5097
12/23/2024
12/24/2024
12/25/2024
12/26/2024
12/27/2024
12/28/2024
12/29/2024 5119 4740 3896 5450 3735 5098
12/30/2024
12/31/2024