Prepared for: Chula Vista Energy Center 2, LLCPrepared by:Ramboll Americas Engineering Solutions, Inc. Los Angeles, California Project Number: 1690003784 Date:June 2025 AIR QUALITY AND GREENHOUSE GAS ANALYSIS CHULA VISTA ENERGY CENTER 2 CHULA VISTA, CALIFORNIA Air Quality and Greenhouse Gas Analysis Chula Vista Energy Center 2 Chula Vista, California i Contents Ramboll
CONTENTS Page 1. INTRODUCTION 11.1 Overview 12. PROJECT DESCRIPTION 22.1.1 Project Background 22.1.2 Project Location 22.1.3 Existing Environment 22.1.4 Project Purpose 22.1.5 Project Description and Entitlement Requirements 23. AIR QUALITY 43.1 Emissions from Construction Equipment 53.2 Emissions from On-Road Trips 73.3 Maximum Daily Emissions and Annual Average Emissions from Project Construction 83.4 Toxic Air Contaminants 103.5 Odors 114. GREENHOUSE GASES 124.1 One-Time Emissions from Construction Phase Activities 134.2 Indirect GHG Emissions from Operational Electricity Use 134.3 Annual GHG Emissions from Project Activities 135. CONCLUSION 15TABLES Table 1: Construction Schedule Assumptions 5Table 2: Construction Equipment Mix Assumptions 6Table 3: Construction Trip Assumptions 8Table 4: Maximum Daily Criteria Air Pollutant Emissions from Project Construction 9Table 5: Annual Average Criteria Air Pollutant Emissions from Project Construction 10Table 6: Construction and Operational Greenhouse Gas Emissions 14 APPENDIXAppendix A: CalEEMod® Output File \\wclaofps1\projects\W\Wellhead Electric\Chula Vista BES\CUP Application\Environmental Review\AQ and GHG Analysis_LIVE.docx Air Quality and Greenhouse Gas Analysis Chula Vista Energy Center 2 Chula Vista, California 1 Introduction Ramboll
1. INTRODUCTION 1.1 Overview This report provides an overview of the air quality analysis conducted for the proposed installation and operation of one 50 megawatt (MW) battery electric storage system (Project) at Chula Vista Energy Center 2 (CVEC2). The purpose of this analysis is to evaluate potential impacts on ambient air quality during both the construction and operational phases of the Project. The applicable guidance for this analysis is derived from the United States Environmental Protection Agency (USEPA), California Air Resources Board (CARB), and the San Diego County Air Pollution Control District (SDAPCD). The thresholds of significance, available in Table 4, are used to determine potential impacts are based on the SDAPCD's Air Quality Impact Analysis (AQIA) trigger levels, as outlined in Rules 20.2 and 20.3, and the South Coast Air Quality Management District’s Air Quality Significance Thresholds, used by the City of Chula Vista.
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2. PROJECT DESCRIPTION 2.1.1 Project Background Chula Vista Energy Center 2, LLC (CVEC2 LLC) is proposing to install one 50 MW battery electric storage system (BESS), the Chula Vista Energy Center 2 (CVEC2 or Project), which will provide local and regional ancillary services to the electric grid to benefit the residents of the City of Chula Vista (City) and adjacent cities. 2.1.2 Project Location The Project site is a 1.9-acre area on an approximately 3.82-acre parcel located at 3497 Main Street, Chula Vista, California, 91911, over 800 feet south of Main Street (Figure 1). The southern portion of the parcel is developed with the Chula Vista Energy Center, LLC (CVEC), an electricity generating power plant. CVEC2 LLC seeks to develop CVEC2 on the northern, undeveloped portion of the parcel, and CVEC2 will be operated independently from the existing CVEC. The site is located in an area zoned as Limited Industrial (I-L) under the City General Plan and is surrounded by limited industrial land uses on the west, north, and east sides, and by the Otay Valley Regional Park on the south side. 2.1.3 Existing Environment The site is adjacent to a meat processing facility on the west side; a printing business and metalworking business on the east side; and an auto dealership, towing business, and recycling center on the north side; which are all limited industrial uses. The Otay ValleyRegional Park immediately south of the parcel is a major urban park and open space area. The closest residential neighborhood is 0.07 miles west of the site. 2.1.4 Project Purpose The Project is designed to receive energy from an interconnection point with San Diego Gas & Electric (SDG&E) during high-renewables-supply/low-demand hours (typically between 9 a.m. and 3 p.m.), store this energy in batteries, and later discharge the energy back to the grid during periods of low-renewables-supply/high-demand, typically between 6 and 10 p.m. The Project, along with other utility-scale battery energy facilities throughout California, is a critical public utility facility necessary to store solar-generated daytime power for overnight use, stabilize voltage from fluctuating renewable power generation sources, and provide local generation capacity in the event regional SDG&E transmission lines are inoperative or de-energized during a Public Safety Power Shutdown high-wind period. 2.1.5 Project Description and Entitlement Requirements The Project requires both a Conditional Use Permit and a Design Review. The Project will use the following energy storage battery equipment configuration: (1) Tesla Megapack lithium-ion batteries housed in fully-enclosed, unoccupied purpose-built containers that are temperature-controlled and constructed in compliance with the applicable California Fire Code requirements, (2) inverters and transformers that will convert alternating current electric energy into direct current electrical energy and the reverse when discharging to the grid, and (3) switchgear and other safety equipment specified by the California Electric Code and/or SDG&E. A new fire road through the site and a new retaining wall will be constructed. The Project will be connected to the SDG&E transmission system by an existing 69 kilovolt (kV) transmission line connected to the SDG&E Otay 69kV substation, located within 1,300 feet north of the Project site. SDG&E is proposing to replace 4-5 existing poles, which would be categorically exempt from the California Environmental Quality Act (CEQA) under Air Quality and Greenhouse Gas Analysis Chula Vista Energy Center 2 Chula Vista, California 3 Project Description Ramboll
California Public Utilities Commission General Order No. 131-D.2 Additionally, SDG&E is proposing to install ~1,300 feet of fiber optic cable on the same existing poles. The proposed Project will be unstaffed and designed for completely remote operation andinclude a security system for remote monitoring 24 hours per day, 7 days per week. Noparking spaces are required based on the number of employees per Chula Vista Municipal Code (CVMC) 19.62.050; however, the Project will use two parking spots internal to the facility for occasional maintenance vehicles.3 Local San Diego area operations personnel will be dispatched to the site as needed in response to continuous monitoring of site alarms and conditions, with support by emergency response personnel if alarm conditions warrant. The maximum height of the battery units will be 9 feet 1 inch, and the maximum height of the generator step-up transformer will be 22 feet 9 inches. The Project will apply for a separate sign permit for a business identification sign as needed. External access to the Project site will be via existing entrances from Main Street and existing driveways for CVEC. Internal site access will be provided via a fire truck access road with necessary turnarounds. The Project parcel will continue to be enclosed with a 10-foot chain link fence with wood slats. Remote monitoring cameras will cover the entire site and monitor 24 hours per day. Existing landscaping features include a landscape screen of Brisbane Box (Tristania conferata) trees immediately on the exterior of a 10-foot chain link fence with opaque screening around the CVEC facility. No changes to the existing landscaping features are being proposed for the Project. Additional landscaping is proposed on the interior, west of the generator step-up transformer. The total resulting lot coverage of landscape area will be 16%. The CVEC2 BESS will be a 50 MW project, with additional space included in the site plan for augmentation. Augmentation is the installation of additional energy storage equipment at a later date to replace lost storage capacity from normal system degradation of the BESS’s battery cells.
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3. AIR QUALITY USEPA, CARB, and the SDAPCD have established air monitoring plans designed to obtain representative data on the ambient levels of pollutants. This data is used to classify an area as attainment, unclassified, or nonattainment, depending on whether the monitored ambient air quality data indicates compliance, sufficient data is not available, or non-compliance with the ambient air quality standards, respectively. In general, an area is designated as attainment if the concentration of a criteria air pollutant does not exceed the standard. Likewise, an area is designated as nonattainment for an air contaminant if the standard is violated. The Project site is located in the San Diego Air Basin (SDAB), which is designated as nonattainment for the federal and state ozone standards, and for the state standards for particulate matter less than 2.5 microns (PM2.5) and particulate matter less than 10 microns (PM10).1 The SDAB is designated as attainment or unclassified for the federal and state standards for carbon monoxide (CO), nitrogen dioxide, and sulfur dioxide (SO2), and for the federal standards for PM2.5 and PM10. In order to establish if a project could cause a significant impact to ambient air quality as defined by CEQA, SDAPCD has established AQIA trigger levels for criteria pollutants for new, non-major stationary sources, outlined in Rules 20.2 and 20.3.2,3 Although these trigger levels do not generally apply to mobile sources or general land development projects, the Guidelines for Determining Significance for Air Quality from the County of San Diego state that these levels may be used for comparative purposes to evaluate the increased emissions from proposed land development projects.4 These levels are applied as screening-level thresholds for potential impact significance of the Project (see Table 4 in Section 3.2.3). The City of Chula Vista uses the South Coast Air Quality Management District’s Air Quality Significance Thresholds to assess the significance of air quality impacts, which are also applied.5,6 1 SDAPCD. 2024. Attainment Status. Available at: https://www.sdapcd.org/content/sdapcd/planning/attainment-status.html. Accessed: March 2024. 2SDAPCD. 2019. Rule 20.2 – New Source Review - Non-Major Stationary Sources, Table 20.2 – 1. Available at: https://www.sdapcd.org/content/dam/sdapcd/documents/rules/current-rules/Rule-20.2.pdf. Accessed: March 2024. 3 SDAPCD. 2019. Rule 20.3 – New Source Review - Major Stationary Sources and PSD Stationary Sources, Table 20.3 – 1. Available at: https://www.sdapcd.org/content/dam/sdapcd/documents/rules/current-rules/Rule-20.3.pdf. Accessed: March 2024. 4 County of San Diego. 2007. Guidelines for Determining Significance for Air Quality. Available at: https://www.sandiegocounty.gov/content/dam/sdc/pds/ProjectPlanning/docs/AQ-Guidelines.pdf. Accessed: March 2024. 5 City of Chula Vista. 2012. A Final Supplemental Environmental Impact Report for Amendments to the City of Chula Vista General Plan (GPA-09-01) and Otay Ranch General Development Plan (PCM-09-11). Available at: https://www.chulavistaca.gov/home/showpublisheddocument/11414/635845576034170000. Accessed: May 2024. 6 South Coast Air Quality Management District. South Coast AQMD Air Quality Significance Thresholds. Available at: https://www.aqmd.gov/docs/default-source/ceqa/handbook/south-coast-aqmd-air-quality-significance-thresholds.pdf?sfvrsn=25. Accessed: May 2024.
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Operational emissions for the proposed Project are expected to be negligible, as the Project will be used only as a battery energy storage facility and not an emitting facility. The liquid cooling systems used to cool the battery containers will use a coolant fluid and be powered with electricity, rendering the on-site operational criteria air pollutant emissions essentially zero. Construction phase emissions at the Project site will consist of emissions from site grading, off-road construction equipment, and on-road construction vehicles. Construction phase emissions will be short-term and are anticipated to occur over a roughly 4-month period (see Table 1). Potential air emissions associated with the Project’s construction phase activities were estimated using the California Emissions Estimator Model (CalEEMod®).7 Assumptions used in the CalEEMod® simulation are presented in the following subsections. CalEEMod®output files are presented in Appendix A. Table 1: Construction Schedule Assumptions Construction Phase Name1 CalEEMod® Phase Type1 Start Date1 End Date1Work Days/ Week Phase Duration(days) Excavation & Site Clearing Grading 9/8/2025 9/19/2025 5 10 Undergrounds Building Construction 9/19/2025 10/17/2025 5 21 Foundations/ Pilings Building Construction 10/20/2025 11/7/2025 5 15 Receive & Set Equipment Building Construction 11/10/2025 12/12/2025 5 25 Electrical Structures Building Construction 11/1/2025 11/30/2025 5 20 Wire Terminations Building Construction 11/10/2025 1/9/2026 5 45 Notes: 1 Construction phases and durations are based on project-specific estimates. PM emissions will be composed of engine exhaust emissions and fugitive emissions. Exhaust emissions are typically emitted by the combustion engines of on-road vehicles and/or off-road equipment. Fugitive emissions are PM dust suspended in the air by wind action and construction-related activities. 3.1 Emissions from Construction Equipment Construction equipment emissions were estimated from off-road equipment engine usage based on equipment lists and phase durations. The fugitive emissions resulting from off-road equipment usage are also included in this analysis. 7 CAPCOA. 2022. California Emissions Estimator Model. Available at: www.caleemod.com. Accessed: March 2024.
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Since the majority of the off-road construction equipment used for construction projects are diesel-fueled, CalEEMod® assumes all of the equipment operates on diesel fuel. There will be no starting or evaporative emissions associated with the construction equipment as these are considered de minimis for diesel-fueled equipment. CalEEMod®calculates the exhaust emissions based on default values for horsepower and load factor taken from the CARB OFFROAD2017-ORION and OFFROAD2011 models.8 Default on-site equipment lists in CalEEMod®were supplemented with project-specific equipment counts for the various construction phases. The list of estimated construction equipment for each construction phase is presented in Table 2. Table 2: Construction Equipment Mix Assumptions Construction Phase Name CalEEMod® Phase Type Equipment Type Number of Equipment/ Day Hours/Day1 Horsepower1 Load Factor1Excavation & Site Clearing2 Grading Graders 1 8 148 0.41 Rubber Tired Dozers 1 8 367 0.4 Tractors/ Loaders/ Backhoes 2 7 84 0.37 Excavators 1 8 36 0.38 Undergrounds3 Building Construction Tractors/ Loaders/ Backhoes 1 6 84 0.37 Cranes 1 6 367 0.29 Forklifts 1 6 82 0.2 Foundations/ Pilings3 Building Construction Tractors/ Loaders/ Backhoes 1 6 84 0.37 Cranes 1 6 367 0.29 Forklifts 1 6 82 0.2 Receive & Set Equipment4 Building Construction Cranes 1 6 367 0.29 Forklifts 1 6 82 0.2 Electrical Structures5 Building Construction Generator Sets 1 8 14 0.74 Welders 3 8 46 0.45 8 CAPCOA. 2022. California Emissions Estimator Model User Guide. Appendix C. Pages 9-10. Version 2022.1. April. Available at: https://www.caleemod.com/documents/user-guide/04_Appendix%20C.pdf. Accessed: March 2024.
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Table 2: Construction Equipment Mix Assumptions Construction Phase Name CalEEMod® Phase Type Equipment Type Number of Equipment/ Day Hours/Day1 Horsepower1 Load Factor1Wire Terminations6Building ConstructionNo Equipment 0 -- -- -- Notes: 1 Equipment operation hours, horsepower, and load factor are based on CalEEMod® default assumptions. 2 Excavation and Site Clearing equipment list is based on CalEEMod® defaults for grading-type phase, with the addition of an excavator to be used for existing soil removal. 3 Equipment lists for Undergrounds and Foundations/Pilings phases are based on CalEEMod®defaults for building construction-type phase. The default welders and generator sets were removed because they are expected to only be used during the Electrical Structures phase. 4 Receive & Set Equipment list is based on CalEEMod® defaults for building construction-type phase. The default welders, generator sets, and tractors/loaders/backhoes were removed due to the expected nature of this phase. 5 Electrical Structures equipment list is based on expected activities at the site, consisting of welding and other electrical structure construction. 6 The Wire Terminations phase is not expected to have any diesel-fueled equipment. Equipment used in this phase is expected to be electric-powered or handheld. CalEEMod®was also used to calculate fugitive dust associated with the excavations and site clearing phase from three major activities: haul road grading, earth bulldozing and excavation, and truck loading. The number of acres graded/bulldozed/excavated will be 1.74 acres.9 Fugitive emissions from truck loading are based on a conservative estimate of the volume of soil to be imported (2,000 cubic yards) and exported (1,760 cubic yards). PM2.5and PM10 emissions from fugitive dust will be controlled by watering the construction site twice daily, or other equivalent stabilization methods in accordance with SDAPCD Rule 55.10CalEEMod®defaults assume watering the construction site twice a day reduces the fugitive dust emissions by 61%. 3.2 Emissions from On-Road Trips Construction activities can generate on-road vehicle exhaust (including evaporative emissions), and entrained road dust emissions from personal vehicles for worker/vendor commuting and trucks for soil/materials hauling. These emissions were calculated in the CalEEMod®model based on the numbers of trips (Table 3) and vehicle miles traveled, along with emission factors from EMFAC2021. Ten worker trips per day were assumed for all phases of the phase type Building Construction. The worker trips per day for the Excavation & Site Clearing phase is based on the CalEEMod® default. The number of vendor trips represent defaults from CalEEMod®, with the exception of the Undergrounds and Receive & Set Equipment phases, which assume four vendor trips per day. The number of haul trips for 9 The site is 1.9 acres, but only 1.74 acres will be graded for this project due to existing foliage. 10SDAPCD. 2005. Rule 55 – Fugitive Dust Control. Available at: https://www.sdapcd.org/content/dam/sdapcd/documents/rules/current-rules/Rule-55.pdf. Accessed: March 2024.
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the Excavation & Site Clearing phase represent defaults from CalEEMod®. During the Receive & Set Equipment phase, there are 16 one-way hauling trips per day, which represent eight trucks that travel to and from the Project site each day to deliver batteries. The mobile source emissions were calculated using trip rates and lengths, as well as emission factors from EMFAC2021 as outlined in the CalEEMod® user’s guide.11Table 3: Construction Trip Assumptions Construction Phase NameWorker Trips per Day1Vendor Trips per Day2Hauling Trips per Day3Excavation & Site Clearing 13 0 47Undergrounds 10 4 0 Foundations/Pilings 10 0 0Receive & Set Equipment 10 4 16 Electrical Structures 10 0 0 Wire Terminations 10 0 0 Notes: 1 Worker trips are presented as one-way trips and assume ten worker trips per day for all phases of the CalEEMod® phase type Building Construction. The worker trips per day for the Excavation & Site Clearing phase is based on the CalEEMod® default. The one-way trip length for worker trips is 11.97 miles, based on the CalEEMod® default for San Diego County. 2 Vendor trips are presented as one-way trips and are based on CalEEMod® defaults, with the exception of the Undergrounds and Receive & Set Equipment phases, which assume four vendor trips per day. The one-way trip length for vendor trips is 7.63 miles, based on the CalEEMod® default for San Diego County. 3 Haul trips are presented as one-way trips per day. The number of haul trips for the Excavation & Site Clearing phase are based on CalEEMod® defaults. The hauling trip distance for the Excavation & Site Clearing phase is based on the CalEEMod® default of 20 miles. The number of haul trips for the Receive & Set Equipment phase is based on project-specific information. The hauling trip distance of 459 miles for the Receive & Set Equipment phase is based on project-specific information. 3.3 Maximum Daily Emissions and Annual Average Emissions from Project Construction The maximum daily and average annual criteria air pollutant emissions estimated due to construction of the Project are summarized in Tables 4 and 5. Detailed CalEEMod® outputs can be found in Appendix A. The estimated emissions show that the daily and annual emissions for construction are less than the daily and annual SDAPCD AQIA trigger levels used as screening-level thresholds for all criteria pollutants, and that the daily emissions for construction are less than the City of Chula Vista daily air quality significance thresholds. Since the Project impacts are minimal and temporary in nature, they will not contribute to a cumulative impact in the Project area. 11CAPCOA. 2022. California Emissions Estimator Model User Guide. Appendix C. Pages 19. Version 2022.1. April. Available at: https://www.caleemod.com/documents/user-guide/04_Appendix%20C.pdf. Accessed: March 2024.
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Table 4: Maximum Daily Criteria Air Pollutant Emissions from Project Construction Scenario Maximum Daily Emissions (lb/day)1VOC2 NOX CO SOx3 PM10PM2.5 Project – 2025 2.20 38.70 22.80 0.18 7.87 2.69 Project – 2026 0.04 0.03 0.38 0.00 0.08 0.02 Maximum 2.2 38.7 22.8 0.2 7.9 2.7 County of San Diego Screening-Level Threshold475 250 550 250 100 55 City of Chula Vista Significance Threshold5 75 100 550 150 150 55 Exceeds Thresholds for any Year of Construction? No No No No No No Notes: NOX – nitrogen oxides SOX – sulfur oxides VOC – volatile organic compounds 1 Emissions reported as zero are non-zero values; these values are rounded to meaningful reporting levels. 2 For purposes of this analysis, VOC emissions are assumed to be equal to reactive organic gases (ROG in CalEEMod®). 3 For purposes of this analysis, SOx emissions are assumed to be equal to SO2. 4 Screening-level thresholds obtained from County of San Diego Guidelines for Determining Significance for Air Quality. Available at: https://www.sandiegocounty.gov/content/dam/sdc/pds/ProjectPlanning/docs/AQ-Guidelines.pdf. Accessed: June 2025. 5The City of Chula Vista uses the South Coast Air Quality Management District thresholds to assess the significance of air quality impacts. Available at: https://www.aqmd.gov/docs/default-source/ceqa/handbook/south-coast-aqmd-air-quality-significance-thresholds.pdf?sfvrsn=25. Accessed: June 2025.
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Table 5: Annual Average Criteria Air Pollutant Emissions from Project Construction Scenario Annual Average Emissions (tpy)1VOC2 NOX CO SOx3 PM10 PM2.5Project – 2025 0.03 0.65 0.41 < 0.005 0.12 0.05 Project – 2026 < 0.005 < 0.005 < 0.005 0.0 < 0.005 < 0.005 Maximum 0.0 0.7 0.4 0.0 0.1 0.1 County of San Diego Screening-Level Threshold413.7 40 100 40 15 10 Exceeds Threshold for any Year of Construction? No No No No No No Notes: tpy – tons per year 1 Emissions reported as zero are non-zero values; these values are rounded to meaningful reporting levels. 2 For purposes of this analysis, VOC emissions are assumed to be equal to reactive organic gases (ROG in CalEEMod®). 3 For purposes of this analysis, SOx emissions are assumed to be equal to SO2. 4 Screening-level thresholds obtained from County of San Diego Guidelines for Determining Significance for Air Quality. Available at: https://www.sandiegocounty.gov/content/dam/sdc/pds/ProjectPlanning/docs/AQ-Guidelines.pdf. Accessed: June 2025. 3.4 Toxic Air Contaminants Diesel particulate matter (DPM) will be emitted during Project construction. Diesel-fueled construction equipment will release DPM, as will diesel-fueled trucks used for vendor or hauling trips during construction. DPM is expected to be equivalent to PM10 emissions from diesel-fueled trucks. While Project construction will result in some DPM emissions, it is not expected that these emissions will result in adverse health risk impacts for workers and residents. Current CEQA guidance does not require a health risk assessment for all construction projects.12 The Office of Environmental Health Hazard Assessment currently recommends that exposure durations of 30 and 25 years be assumed for residential and worker receptors, respectively, to estimate cancer risk and hazard indices.13 Since the diesel equipment usage during the construction period for this Project is only 4 months, the Project is not expected to result in a 12Association of Environmental Professionals. 2025. California Environmental Quality Act Statute & Guidelines. Available at: https://www.califaep.org/docs/CEQA_Handbook_2025combined.pdf. Accessed: June 2025. 13Office of Environmental Health Hazard Assessment. February 2025. Guidance Manual for Preparation of Health Risk Assessments. Available at: https://oehha.ca.gov/media/downloads/crnr/2015guidancemanual.pdf. Accessed: June 2025.
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long-term increase in DPM emissions nor is it expected to have adverse health risk impacts.14 3.5 Odors Construction equipment are typically fueled by diesel, which could lead to odors. However, diesel-fueled construction equipment will use low sulfur-content fuel, which will minimize potential odors. There are a few sensitive receptors near the activities of this Project: Otay Elementary School, located 0.24 miles to the north, and residences 380 feet to the west. Given the intermittent and temporary nature of construction activities, potential odors are not expected to be discernible to offsite receptors. Diesel trucks that will be operated on-site as part of construction activities will not be allowed to idle longer than five minutes in any one location, in accordance with the CARB idling Airborne Toxics Control Measure (13 CCR §2485).15 No construction-related truck will be allowed to park, idle, or stage along Main Street. Staging will be limited to certain areas minimize impacts on neighboring business operations or traffic. Therefore, construction equipment and haul trucks are not expected to generate diesel exhaust odor greater than typically present at the Project site. 14Estimate of Project construction schedule duration does not include the wire terminations phase, as there is no construction equipment associated with that phase. Further, no diesel-fueled vendor or hauling truck trips are expected during that phase. 15 13 CCR §2485. Airborne Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling. https://ww2.arb.ca.gov/sites/default/files/2022-06/13_CCR_2485_OAL_06222022-2_ADA_06272022_0.pdf. Accessed: March 2024.
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4. GREENHOUSE GASES Gases that trap heat in the atmosphere are called greenhouse gases (GHGs). The Project was evaluated against the following GHG reduction report and plans: • 2021 SB100 Joint Agency Report (2021 Report): Charting a Path to a 100% Clean Energy Future16: Senate Bill 100 (SB 100) established a policy requiring renewable energy and zero-carbon resources to supply 100 percent of electric retail sales by 2024. It requires the California Energy Commission, California Public Utilities Commission and CARB to submit a report to the legislature every four years. The 2021 Report assesses pathways to achieve the California target of 100 percent of electricity retail sales and state loads from renewable and zero-carbon resources by 2045. The report notes that energy storage is a key technology to achieving SB 100 goals and states that it is expected to play a significant role in helping balance the grid as the state implements SB 100. • CARB 2022 Scoping Plan for Achieving Carbon Neutrality (Scoping Plan)17: The Scoping Plan provides a sector-by-sector path for California to achieve carbon neutrality by 2045 or earlier. The Scoping Plan outlines a technologically feasible, equity focused, cost-effective pathway for achieving the state’s climate target. The Scoping Plan identifies energy storage as a cost-effective solution, noting that they are cheaper than polluting alternatives and are already a part of the business-as-usual approach. The Scoping Plan states that decarbonizing the electricity section is a crucial pillar of the plan and “depends on both using energy more efficiently and replacing fossil-fueled generation with renewable and zero-carbon resources, including solar, wind, energy storage, geothermal, biomass, and hydroelectric power.” • 2017 Chula Vista Climate Action Plan (CVCAP)18: The CVCAP describes the actions, measurement development, implementation, and progress toward reducing GHG emissions. One of their primary goals for renewable and efficient energy is to have clean energy sources. While not specifically addressing battery energy storage, the plan is clear in its goal of clean energy sources. • 2024 Chula Vista Climate Action Plan Update Summary19: In the 2024 CVCAP Update Summary, the plan envisions installing zero emission technologies like heat pumps and solar with battery storage. This Project is therefore consistent with existing plans and the 2021 SB100 Joint Agency Report. The Project will result in both one-time and annual direct and indirect emissions of GHGs. The term “direct emissions of GHGs” refers to GHGs that are emitted directly as a result of the Project and include land use change and construction emissions. Indirect emissions are 162021 SB 100 Joint Agency Report: CEC, CPUC, CARB. Available at: https://www.energy.ca.gov/sb100. 172022 Scoping Plan for Achieving Carbon Neutrality, CARB. Available at: https://ww2.arb.ca.gov/sites/default/files/2023-04/2022-sp.pdf. 18Chula Vista 2017 Climate Action Plan. Available at: https://www.chulavistaca.gov/home/showpublisheddocument/15586/636428706054030000. 19Chula Vista 2024 Climate Action Plan Update Summary. Available at: https://www.chulavistaca.gov/home/showpublisheddocument/28413/638591444819970000.
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those emissions that the Project will enable, but that are not controlled by the Project proponent. Construction of the Project will generate direct one-time GHG emissions through combustion of fuel in construction equipment and vehicles. Operation of the Project will result in indirect GHG emissions from electricity used by the on-site liquid cooling systems if the source of power is from a non-renewable generation source. These GHG emissions were estimated using CalEEMod®. Assumptions used in the CalEEMod® simulation are presented in the following subsections. 4.1 One-Time Emissions from Construction Phase Activities One-time construction emissions were based on a mix of project-specific estimates including the numbers and types of equipment that will be used, on-road vehicle trips from haul trucks, vendors, and workers, as well as the duration of the construction phases. The construction equipment parameters (horsepower, load factor, and hours of operation) and trip quantities were based on CalEEMod® default data and project-specific data when available. Construction vehicle trip distances are based on CalEEMod® default assumptions. The Project construction was assumed to occur over a 4-month period, starting in September 2025. The equipment lists, construction-related on-road trips, and construction schedule are shown in Section 3.2, above. Further details regarding construction emissions can also be found in Section 3.2. CalEEMod® output files can be found in Appendix A. 4.2 Indirect GHG Emissions from Operational Electricity Use Project-related electricity use results in indirect emissions due to electricity generation activities occurring at offsite non-renewable power plant locations. For this Project, electrical power will be supplied by San Diego Gas & Electric (SDG&E). The indirect GHG emissions created as a result of project-related electricity use are estimated using intensity factors for SDG&E and the project-specific electricity use associated with the on-site liquid cooling system(s) of 4,760 kWh/day. The default electricity intensity for SDG&E in CalEEMod® for carbon dioxide (CO2), methane, and nitrous oxide are 588.983, 0.033, and 0.004 pounds (lbs) per megawatt-hour (MWh), respectively. 4.3 Annual GHG Emissions from Project Activities In 2013, the County of San Diego developed project-specific implementing thresholds as part of their Guidelines for Determining Significance for Climate Change.20 Although another version of the County’s guidelines was released in 2018, no quantitative emissions thresholds are presented. As a conservative assessment of quantitative GHG significance, this analysis compares estimated GHG emissions against thresholds found in the 2013 version of the County’s guidance. The Bright Line Threshold of 2,500 metric tons of CO2 equivalent emissions per year (MT CO2e/yr) is the most conservative threshold used earliest to screen out small projects that are presumed to have less-than-cumulatively considerable impact. For larger projects, if the project type is a stationary source, the Stationary Source Threshold of 10,000 MT CO2e can be used to evaluate the stationary source, and the Bright Line Threshold to assess any area or mobile emissions sources involved. Such projects with incremental increases below 20 County of San Diego. 2013. Guidelines for Determining Significance for Climate Change. Available at: https://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/Soitec-Documents/Final-EIR-Files/references/rtcref/ch3.1.3/2014-12-19_CountyofSD2013.pdf. Accessed: March 2024.
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this threshold will not be cumulatively considerable. As shown in Table 6, the Project GHG emissions are well below both the 2,500 and 10,000 MT/year CO2e implementing thresholds. Table 6: Construction and Operational Greenhouse Gas Emissions Emission Source Calendar Year CO2e Emissions(MT/year) Construction Emissions 2025 376.0 2026 0.3 County of San Diego Bright Line Threshold12,500Exceeds Threshold for Any Year of Construction? No Operational Emissions Annual466Construction Emissions, 20-Year Amortization 19 Operational Total 485 County of San Diego Stationary Source Threshold1 10,000 Exceeds Threshold? No Notes: 1 Implementing thresholds obtained from County of San Diego Guidelines for Determining Significance for Climate Change. Available at: https://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/Soitec-Documents/Final-EIR-Files/references/rtcref/ch3.1.3/2014-12-19_CountyofSD2013.pdf. Accessed: June 2025. The construction and operational activities are not expected to generate GHG emissions, either directly or indirectly, that may have a significant impact on the environment or conflict with any applicable adopted plans, policies or regulations for the purpose of reducing the emissions.
Air Quality and Greenhouse Gas Analysis Chula Vista Energy Center 2 Chula Vista, California 15 Conclusion Ramboll
5. CONCLUSIONThis air quality and greenhouse gas analysis has been conducted to evaluate the potentialimpacts of the proposed 50 MW BESS. The analysis of the emissions from equipment andon-road trips from the construction phase showed that both the maximum daily and annualaverage emissions for all criteria pollutants are well below the screening-level thresholdsestablished by the SDAPCD and the City of Chula Vista. Additionally, operational emissionsare expected to be negligible since the Project will function solely as a battery energystorage facility with no significant on-site emissions. Potential odors from diesel-fueledconstruction equipment will be minimized through the use of low sulfur-content fuel andadherence to CARB idling regulations and are not expected to impact nearby sensitivereceptors.The Project's GHG emissions are below the County of San Diego’s Bright Line and StationarySource thresholds. Therefore, the construction and operational activities are not expected togenerate GHG emissions, either directly or indirectly, that may have a significant impact onthe environment or conflict with any applicable adopted plans, policies or regulations for thepurpose of reducing the emissions.The proposed project was found to have less than significant impacts or no impacts on airquality and GHG. There will also be no cumulative impacts resulting from the Project. Nofurther analysis of these areas is required.
Air Quality and Greenhouse Gas Analysis Chula Vista Energy Center 2 Chula Vista, California APPENDIX A CALEEMOD® OUTPUT FILE Ramboll