DAQ-2024-012007

1
DAQC-CI157160001-24
Site ID 15716 (B1)

MEMORANDUM

TO: FILE – CITY OF LEHI POWER – Power Plant

THROUGH: Chad Gilgen, Minor Source Compliance Section Manager

FROM: Jordan Garahana, Environmental Scientist

DATE: December 2, 2024

SUBJECT: FULL COMPLIANCE EVALUATION, Minor, Utah County

INSPECTION DATE: July 11, 2024

SOURCE LOCATION: 1800 West Vialetto Way
Lehi, UT 84032

DIRECTIONS: The address listed on the AO is incorrect. The actual address is
560 West Glen Carter Drive, Lehi. From I-15 take exit 282 to 89
South West State Road. Glen Carter Drive is located near 300
North and 500 West.

SOURCE CONTACTS: Joel Eves, Power Department Director
385-201-2630, [e-mail]

Crystal Robinson, Forecast Manager
385-201-2630, [e-mail]

Jason Bond, Power/Management Analyst
385-201-1000, [e-mail]

OPERATING STATUS: Operating normally at the time of inspection.

PROCESS DESCRIPTION: The city of Lehi operates a peaking power plant that generates
power for the city during times of high demand. The power plant
is permitted for six natural gas-fired engines rated at 2.4 MW
and four engines rated at 4 MW. The engines are equipped with
selective catalytic reduction and oxidation catalysts to control
emissions. The plant also operates a diesel-fired emergency
generator to supply power to the office building.

APPLICABLE REGULATIONS: Approval Order (AO) DAQE-AN157160001-17, dated
April 19, 2017

NSPS (Part 60) IIII : Standards of Performance for Stationary
Compression Ignition Internal Combustion Engines,
NSPS (Part 60) JJJJ : Standards of Performance for Stationary
Spark Ignition Internal Combustion Engines,
* - ) - # )
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NSPS (Part 60) A: General Provisions,
MACT (Part 63) -A : General Provisions,
MACT (Part 63) -ZZZZ: National Emissions Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines
SOURCE EVALUATION:
Name of Permittee: Permitted Location:
City of Lehi Power Power Plant
560 West Glen Carter Drive 1800 West Vialetto Way
Lehi, UT 84043 Lehi, UT 84032
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]

Status: In Compliance. No breakdowns have occurred since the previous inspection. No
unapproved equipment was observed, and no limits have been exceeded. Source submitted
their 2023 Emission Inventory by the required submission date. See the attachments section
for additional information.

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Section II: SPECIAL PROVISIONS

II.A The approved installations shall consist of the following equipment:

II.A.1 City of Lehi Power

II.A.2 Caterpillar G3520H Generator Sets
Quantity: 6
Rating: 2.4 MW (3,408 hp)
Fuel: Natural Gas
Control: SCR and oxidation catalyst
NSPS/MACT Applicability: 40 CFR 60 Subpart JJJJ

II.A.3 Caterpillar CG-260-16 Generator Sets
Quantity: 2
Rating: 4.0 MW (5,519 hp)
Fuel: Natural Gas
Control: SCR and oxidation catalyst
NSPS/MACT Applicability: 40 CFR 60 Subpart JJJJ

II.A.4 Emergency Generator
Quantity: 1
Rating: 736 bhp
Fuel: Diesel
NSPS/MACT Applicability: 40 CFR 60 Subpart IIII

**Manufacturer and models listed for informational purposes only.

Status: In Compliance. No unapproved equipment was observed. All the generators have
been installed, stack tested, and are now operational.

Additional information carried over from the previous inspection:

II.A.2 Caterpillar G3520H Generator sets – all 6 generators were observed to be
installed and operational at the time of inspection.

II.A.3 Caterpillar CG-260-16 – both generators were observed to be installed and
operational.

II.A.4 – The emergency generator is a 2014 Caterpillar ISO8528 Model with a
non-resettable meter.

There are two 10,000-gallon Urea tanks installed inside by the generators. Both tanks
are operational.

There is one diesel storage tank located outdoors on the west side of the building. See
DAQC-1406-20 for additional information about this tank.

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II.B Requirements and Limitations

II.B.1 Facility-Wide Requirements

II.B.1.a The owner/operator shall notify the Director in writing when the installation of the equipment
listed in Condition II.A of this AO has been completed and the equipment is operational. To
ensure proper credit when notifying the Director, send your correspondence to the Director, attn:
Compliance Section.

If the owner/operator has not notified the Director in writing within 18 months from the date of
this AO on the status of the construction and/or installation, the Director shall require
documentation of the continuous construction and/or installation of the operation. If a continuous
program of construction and/or installation is not proceeding, the Director may revoke the AO.
[R307-401-18]

Status: Out of Compliance. Notification was made for three of the generators on January
1, 2018, with an initial stack test conducted. The rest of the generators were installed in
2023, and stack tested on October 2, 2023, but no notification of the operational status has
been made. The generators were observed to be in operation at the time of inspection. No
further action is currently recommended.

II.B.1.b Visible emissions from the emission points listed below shall not exceed the following opacity
values:

A. Natural Gas Generator Engines - 10%
B. Diesel Generator Engines - 20%
C. All Other Points - 20%. [R307-201, R307-305, R307-401-8]

II.B.1.b.1 Opacity observations of visible emissions from stationary sources shall be conducted according
to 40 CFR 60, Appendix A, Method 9. [R307-401-8]

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

II.B.2 Natural Gas Generator Engines Requirements

II.B.2.a The owner/operator shall use only natural gas as fuel in all internal combustion engine
generators. [R307-401-8]

Status: In Compliance. Natural gas is the only fuel source utilized in the engine generators.

II.B.2.b Emissions to the atmosphere from each of the natural gas-fired engines shall not exceed the
following rates:

Source: 2.4 MW Generator Engines (Each Stack)

NOx: 0.07 g/bhp-hr

CO: 0.16 g/bhp-hr

VOC: 0.14 g/bhp-hr
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Source: 4.0 MW Generator Engines (Each Stack)

NOx: 0.07 g/bhp-hr

CO: 0.14 g/bhp-hr

VOC: 0.09 g/bhp-hr. [R307-401-8]

II.B.2.b.1 Frequency

Each stack shall be tested at least once every three (3) years. Initial compliance testing is
required. The initial test date shall be performed as soon as possible and in no case later than 180
days after the startup of a new emission source. If an existing source is modified, a compliance
test is required on the modified emission point that has an emission rate limit. [R307-401-8]

II.B.2.b.2 Notification

The Director shall be notified at least 30 days prior to conducting any required emission testing.
A source test protocol shall be submitted to DAQ when the testing notification is submitted to
the Director.
The source test protocol shall be approved by the Director prior to performing the test(s). The
source test protocol shall outline the proposed test methodologies, stack(s) to be tested, and
procedures to be used. A pretest conference shall be held, if directed by the Director.
[R307-401-8]

II.B.2.b.3 Sample Location

The sampling location shall be designed to conform to the requirements of 40 CFR 60, Appendix
A, Method 1, or other methods as approved by EPA and acceptable to the Director. An
Occupational Safety and Health Administration (OSHA) or Mine Safety and Health
Administration (MSHA) approved access shall be provided to the test location. [R307-401-8]
II.B.2.b.4 Volumetric Flow Rate Test Methods 40 CFR 60, Appendix A, Method 2 or other testing methods approved by EPA and accepted by the Director. [R307-401-8] II.B.2.b.5 NOx Test Methods 40 CFR 60, Appendix A, Method 7, 7A, 7B, 7C, 7D, 7E or other EPA approved testing methods approved by the Director. [R307-401-8] II.B.2.b.6 CO Test Methods 40 CFR 60, Appendix A, Method 10, or other EPA approved testing methods approved by the Director. [R307-401-8]
II.B.2.b.7 VOCs Test Methods

40 CFR 60, Appendix A, Method 18, 25, 25A, 40 CFR 63 Appendix A: Method 320,
ASTMD6348, or other EPA approved testing methods approved by the Director. [R307-401-8]

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II.B.2.b.8 Calculations
To determine mass emission rates (lb/hr, etc.) the pollutant concentration as determined by the
appropriate methods above shall be multiplied by the volumetric flow rate and any necessary
conversion factors determined by the Director, to give the results in the specified units of the
emission limitation. [R307-401-8]
II.B.2.b.9 New Source Operation For a new source/emission point, the production rate during all method-testing shall be no less than 90% of the maximum production rate (rated capacity) of the source. If the production rate has not been achieved at the time of the test, method-testing shall be conducted at no less than 90% of the maximum production rate achieved as of the date of the test. [R307-165]
II.B.2.b.10 Existing Source Operation

For an existing source/emission point, the production rate during all compliance testing shall be
no less than 90% of the maximum production achieved in the previous three (3) years.
[R307-401-8]

Status: In Compliance. The source has stack tested all six generator engines on October 2,
2023, listed in II.A.2 on the equipment list. The test results were accepted, and the
generators were tested within 3 years of the previous test in 2020. No generator exceeded
the limits established for VOC, NOx, and CO. For the six 2.4 MW engines, the VOC, NOx,
and CO emission rates from the most recent stack test are as follows:

Engine 1: 0.056 g/bhp-hr NOx, 0.065 g/bhp-hr CO, 0.073 g/bhp-hr VOC
Engine 2: 0.023 g/bhp-hr NOx, 0.054 g/bhp-hr CO, 0.084 g/bhp-hr VOC
Engine 3: 0.059 g/bhp-hr NOx, 0.152 g/bhp-hr CO, 0.077 g/bhp-hr VOC
Engine 4: 0.064 g/bhp-hr NOx, 0.075 g/bhp-hr CO, 0.093 g/bhp-hr VOC
Engine 5: 0.054 g/bhp-hr NOx, 0.063 g/bhp-hr CO, 0.054 g/bhp-hr VOC
Engine 6: 0.053 g/bhp-hr NOx, 0.071 g/bhp-hr CO, 0.087 g/bhp-hr VOC

See DAQC-1372-23 for additional information.

The 2 generators listed in II.A.3 on the equipment list are also subject to stack testing. They
were stack tested on May 9-10, 2024, and the results of the tests were accepted. The results
did not exceed any limits for VOC, NOx, and CO for either generator. The emission rates
for the two 4.0 MW generators are as follows from the most recent stack test:

Unit #4: 0.013 g/bhp-hr NOx, 0.011 g/bhp-hr CO, 0.084 g/bhp-hr VOC
Unit #8: 0.017 g/bhp-hr NOx, 0.019 g/bhp-hr CO, 0.072 g/bhp-hr VOC

See DAQC-711-24 for more information about the results of this stack test.

II.B.3 Emergency Generator Engine

II.B.3.a The owner/operator shall use the emergency generator engine for electricity-producing operation
only during the periods when utility service is interrupted, or for regular maintenance and testing
of the engines. [R307-401-8]

Status: In Compliance. The emergency generator is only operated during emergencies and
for scheduled maintenance. See the attachments section for additional information.
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II.B.3.b The emergency generator engine shall not exceed 100 hours of operation per rolling 12-month
period for maintenance checks and readiness testing. There is no time limit on the use of the
engine during emergencies. [R307-401-8]

II.B.3.b.1 To determine compliance with a rolling 12-month total, the owner/operator shall calculate a new
12-month total by the twentieth day of each month using data from the previous 12 months.
Records documenting the operation of the emergency engine shall be kept in a log and shall
include the following:

A. The date the emergency generator engine was used;

B. The duration of operation each day in hours; and

C. The reason for the emergency generator engine usage. [R307-401-8]

Status: In Compliance. The rolling 12-month total from July 2023 to June 2024 that the
backup generator operated is as follows:

22.8 hours of runtime

The generator operated for maintenance and for 8 hours when power was lost to the main
building during renovations. The totals are stored in a log with the rolling total calculated
monthly. The generator is equipped with a non-resettable meter. See the attachments
section 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) IIII: Standards of Performance for Stationary Compression Ignition Internal Combustion
Engines

Status: In Compliance. The II.A.4 Caterpillar ISO8528 diesel-fired generator applies to this subpart.
The source submitted the manufacturer's certificate of emission standards back in 2017 and maintains
the generator according to the manufacturer's specifications. The generator did not operate more than
100 hours within the rolling 12-month period, with the total hours being 22.8 hours. The engine has a
non-resettable meter installed on it.

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

Status: In Compliance. The six II.A.2 natural gas-fired generators and the two II.A.3 natural gas-fired
generators apply to this subpart. They are maintained according to the manufacturer's specifications
and the source submitted the manufacturer's certificate of emission standards back in 2017. The newly
installed 3 generators are the same make and model of generator and have the same emissions standards
of the previous ones inspected in 2020 and 2022. The manufacturer’s specifications for the new
generators were viewed onsite at the time of inspection. The generators are maintained as previously
mentioned in the 2020 inspection report. See DAQC-1406-20 for additional information.
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NSPS (Part 60) A: General Provisions

Status: In Compliance. Compliance with NSPS Part 60 Subpart A is determined by compliance with
applicable subparts. In Compliance with subpart IIII and JJJJ.

MACT (Part 63) -A: General Provisions

Status: In Compliance. Compliance with subpart A is determined by compliance with applicable
federal subparts. In Compliance with Subpart ZZZZ.

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

Status: In Compliance. The six II.A.2 natural gas-fired generators, the two II.A.3 natural-gas
fired generators, and the II.A.4 diesel powered emergency generator apply to this subpart. They are
maintained according to the manufacturer's specifications and the source submitted the manufacturer's
certificate of emission standards back in 2017 for three of the natural gas generators and the
diesel-powered generator. For the three newly installed II.A.2 natural gas-powered generators, the
manufacturer’s specifications and emission standards were viewed onsite at the time of inspection.
The six II.A.2 generators and the two II.A.3 generators are also subject to Subpart JJJJ, and the
diesel-powered generator is subject to Subpart IIII. Source conducts stack testing on the II.A.2 and
II.A.3 generators to ensure the emission rates are compliant with the standards listed within this AO.
See Subparts IIII and JJJJ for additional compliance information regarding those two Subparts.

AREA SOURCE RULES EVALUATION:

The following Area Source Rules were evaluated during this inspection:

Emission Standards: Sulfur Content of Fuels [R307-203]

Status: In Compliance. The diesel fuel utilized onsite is classified as ULSD, according to a bill of sale
from Christensen Distribution. This bill of sale was viewed onsite at the time of inspection.

Stationary Sources [R307-210]

Status: In Compliance. R307-210 applies as the source is subject to NSPS subparts JJJJ and IIII.
For compliance information, see Section III.

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

Status: In Compliance. R307-214 applies as the source is subject to MACT 63 Subpart ZZZZ. For
compliance information, see Section III.

EMISSION INVENTORY:

Listed below are the Actual Emissions Inventory provided from City of Lehi Power – Power Plant. A
comparison of the estimated total potential emissions (PTE) on AO: DAQE-AN157160001-17, dated
April 19, 2017, is provided. The 2023 Emission Inventory can be found in the attachments section below.
PTE are supplied for supplemental purposes only.
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Criteria Pollutant PTE tons/yr Actuals tons/yr
Carbon Monoxide 46.56
Nitrogen Oxides 21.55
Particulate Matter - PM10 2.66
Particulate Matter - PM2.5 2.66
Sulfur Dioxide 0.47
Volatile Organic Compounds 37.24

Hazardous Air Pollutant PTE lbs/yr Actuals lbs/yr
Acetaldehyde (CAS #75070) 13220
Acrolein (CAS #107028) 8140
Formaldehyde (CAS #50000) 12760
Generic HAPs (CAS #GHAPS) 4040

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

COMPLIANCE STATUS &
RECOMMENDATIONS: In regard to Approval Order (AO) DAQE-AN157160001-17,
dated April 19, 2017: Out of Compliance with condition II.B.a.1
of this AO. The source did not submit the notification to the
DAQ about the operational status of the new equipment listed in
II.A.2. The generators listed in II.A.2 were observed to be
operational at the time of inspection. No further action is
currently recommended.

In compliance with the rest of the conditions listed within the
AO. The facility is well maintained, and records were made
available upon request.

HPV STATUS: Not Applicable.

RECOMMENDATION FOR
NEXT INSPECTION: Inspect during the summer months as this is a peaker facility.

NSR RECOMMENDATIONS: The address needs to be changed, as the location of the plant is
560 West Glen Carter Drive in Lehi. The urea tanks and diesel
fuel tanks should be evaluated.

ATTACHMENTS: Applicable Supporting Documentation Included
2023 Emissions Inventory Report
City of Lehi Power Plant (15716)
Emissions Summary
CRITERIA AIR POLLUTANT (CAP) EMISSIONS TOTALS
Pollutant Code/CAS #Pollutant Name Emissions
(tons, excluding
tailpipe)
Tailpipe
Emissions
(tons)
Total Emissions
(tons)*
PM10-PRI PM10 Primary (Filt + Cond)0.70603 <.00001 0.70603
PM10-FIL PM10 Filterable 0.35081 <.00001 0.35081
PM25-PRI PM2.5 Primary (Filt + Cond)0.70366 <.00001 0.70366
PM25-FIL PM2.5 Filterable 0.34935 <.00001 0.34935
PM-CON PM Condensible 0.35344 <.00001 0.35344
SO2 Sulfur Dioxide 0.02109 <.00001 0.02109
NOX Nitrogen Oxides 1.03463 <.00001 1.03463
VOC Volatile Organic Compounds 1.91104 <.00001 1.91104
CO Carbon Monoxide 1.40827 <.00001 1.40827
NH3 Ammonia 0.00164 <.00001 0.00164

HAZARDOUS AIR POLLUTANT (HAP) and/or OTHER POLLUTANT EMISSIONS TOTALS
Pollutant Code/CAS #Pollutant Name Is VOC/PM? Total Emissions
(tons)*
75070 Acetaldehyde (HAP)VOC 0.298
107028 Acrolein (HAP)VOC 0.18306
71432 Benzene (HAP)VOC 0.01575
106990 1,3-Butadiene (HAP)VOC 0.0095
100414 Ethyl Benzene (HAP)VOC 0.00141
50000 Formaldehyde (HAP)VOC 0.28652
110543 Hexane (HAP)VOC 0.03948
91203 Naphthalene (HAP)VOC 0.00266
130498292 PAH, total (HAP)PM 0.00097
108883 Toluene (HAP)VOC 0.01455
1330207 Xylenes (Mixed Isomers) (HAP)VOC 0.00658

*Rounded to 5 digits past the decimal point. Note that where rounding results in 0, <.00001 is indicated.
1/2
2/2
Date of Engine
Inspection
Engine
Hours Reason
12-Jul-23 103.9 Routine
5-Sep-23 106.4 Routine
25-Sep-23 107 Routine
23-Oct-23 108.2 Routine
13-Nov-23 109.1 Routine
5-Dec-23 117 Backup gen was run to power the building while new equipment was added as part of the expansion of our plant.
19-Dec-23 118.2 Routine
19-Dec-23 118.5 Routine
9-Jan-24 119 Routine
16-Jan-24 119.7 Routine
23-Jan-24 120 Routine
8-Feb-24 120.1 Routine
13-Feb-24 120.5 Routine
21-Feb-24 120.7 Routine
27-Feb-24 121.1 Routine
5-Mar-24 121.4 Routine
12-Mar-24 121.7 Routine
26-Mar-24 122.3 Routine
9-Apr-24 122.6 Routine
8-May-24 123.9 Routine
21-May-24 124.3 Routine
21-May-24 124.5 Routine
28-May-24 124.8 Routine
4-Jun-24 125.1 Routine
26-Jun-24 125.7 Routine
11-Jul-24 126.7 Routine
Jordan Garahana <[e-mail]>
Lehi City Backup Generator Report
2 messages
Jason Bond <[e-mail]>Wed, Jul 17, 2024 at 12:04 PM
To: "[e-mail]" <[e-mail]>
Cc: Crystal Robinson <[e-mail]>, Joel Eves <[e-mail]>
Jordan,

Please find attached the inspection report for Lehi City’s black start generator that you requested from your recent site
visit. This report includes the dates, hours, and reasons for all inspections that took place by one of our technicians.
Please let me know if you need any additional information.

Thank you,

Backup Generator Inspection Report 7.2024-1.xlsx
10K
Jordan Garahana <[e-mail]>Wed, Jul 17, 2024 at 12:56 PM
To: Jason Bond <[e-mail]>
Cc: Crystal Robinson <[e-mail]>, Joel Eves <[e-mail]>
Hey Jason,
Thank you for sending me the hours for the generator. I will let you know if there is anything else I need to complete my
inspection.
Thanks,
Jordan Garahana
[Quoted text hidden]
--
7/29/24, 3:35 PM State of Utah Mail - Lehi City Backup Generator Report
https://mail.google.com/mail/u/0/?ik=038c40f7b3&view=pt&search=all&permthid=thread-f:1804850395689509596&simpl=msg-f:180485039568950959…1/2
Jordan Garahana
Environmental Scientist | Minor Source Compliance
M: [phone]
airquality.utah.gov
Emails to and from this email address may be considered public records and thus
subject to Utah GRAMA requirements.
7/29/24, 3:35 PM State of Utah Mail - Lehi City Backup Generator Report
https://mail.google.com/mail/u/0/?ik=038c40f7b3&view=pt&search=all&permthid=thread-f:1804850395689509596&simpl=msg-f:180485039568950959…2/2