6.10 Gasoline Filling Station Fueling
Categories 75, 76, 77, and 78
6.10.1 Introduction
Category 75, 76, 77, and 78 cover organic emissions (TOG and ROG) from Gasoline filling station fueling. Motor vehicle refueling emissions come from vapors displaced from the automobile tank at gasoline dispensing facilities. The quantity of evaporative emissions depends on gasoline temperature, automobile tank temperature, gasoline RVP and dispensing rate. The control technique for vehicle refueling emissions is Phase II vapor recovery system. Most gasoline dispensing facilities in the Bay Area were equipped with Phase I and/or Phase II vapor recovery systems.The integral part of Phase II vapor recover system is the vapor recovery nozzle and hose that efficiently collect the displaced vapors.The Phase II is equipped with a rubber boot to collect and the route the vapors through the nozzle into a coaxial vapor-liquid hose and to the dispenser and into storage tank.
6.10.2 Methodology
Point Sources
Point Sources are operations that emit air pollution into the atmosphere at a fixed location within a facility, for which the Air District has issued a permit to operate, e.g. refinery cooling towers. These could also be a collection of similar equipment / sources located across multiple facilities, e.g. reciprocating engines.
During the permit to operate (PTO) issuance process, the BAAQMD collects information from the operating facility and/or determines from published literature, e.g. EPA’s AP-42, characteristics of a source including maximum throughput, emission factors for emitted pollutants, and control factors associated with downstream abatement devices. These characteristics are then stored for future use in the BAAQMD’s internal database. Facilities that hold a permit to operate are required to renew this permit periodically (this period varies based on facility and source type). Upon renewal, the facilities are requested to provide any updates to source characteristics as well as the source throughput for the last 12 months. This throughput, in combination with the emission factors and controls factors stored in the internal database, are used to estimate annual emissions at the source level. These source level emissions are then sorted and aggregated into categories.
Category 78 is considered a point source category and follows the above methodology for emissions estimates.
Area Sources
| Category | Description |
|---|---|
| 75 | Filling Vehicle Tanks, without Phase I & II |
| 76 | Filling Vehicle Tanks, with Phase I & II |
| 77 | Filling Vehicle Tanks, with Phase I Only |
The above categories account for evaporative emissions resulting from Breathing and Working losses at gasoline dispensing facilities (GDFs). These categories are considered area source categories since they cover facilities / emission sources that are not directly permitted by the District, and hence not systematically cataloged. Emissions for area source categories are determined using the formula:
Current Year Emissions = Base Year Emission X Growth Profile, and,
Base Year Emission = Throughput X Control Factor X Emission Factor
where,
- throughput or activity data for applicable base year(s) is determined using a top-down approach (e.g. state-, national-level data);
- emission factor is derived from general literature, specific literature and reports, and/or source testing results provided by Air District staff;
- control factor (if applicable) is determined by District and state rules and regulations in effect;
- and, historical backcasting and forecasting of emissions is based on growth profiles as outlined in the Trends section of this chapter
The Breathing and Working total organic gas (TOG) methodologies for area source categories (75, 76, 77) were based on CARB’s Miscellaneous Process Methodology, Gas Dispensing Facilities, Section 4.10. 190 The annual throughput estimates of gasoline consumption in the Bay Area were obtained from California Energy Commission (CEC).The TOG emissions are determined by multiplying the throughput, emission factor, and control factor.
More details on throughput, county distribution, emission factors and controls is provided in the following subsections.
(a) Activity Data / Throughput
The estimates of gasoline consumption in the Bay Area were obtained from California Energy Commission (CEC) , California Annual Retail Fuel Outlet Report Results191 report.
(b) County Distribution / Fractions
County annual gasoline fuel consumption distributed into the Bay Area counties were based on CEC California Annual Retail Fuel Outlet Report County breakdown. The gasoline consumption throughput for Solano and Sonoma counties is apportioned based upon CEC’s throughput and CARB’s county estimated emissions.
(c) Emission Factors
The current base year inventory Gasoline Filling Station Fueling emission factors were derived from CARB’s Revised Emission Factors for Gasoline Marketing Operations at California Gasoline Dispensing Facilities192.
(d) Control Factors
Emissions were reduced due to the effect of District’s Regulation 8, Rule 7: Gasoline Dispensing Facilities193, Phase II requirements and the following actions:
- In July 1976, California Health & Safety Code required CARB certified 90% Phase II gasoline dispensing facilities.
- In August 1978, CARB amended Phase II GDFs to 95% efficiency.
- In July 1986, CARB issued “Rectification Orders”.
- In October 1990, District adopted pressure-vacuum valve requirements for GDFs.
- In March 2000, California Air Resources Board (CARB) adopted a series of new Enhanced Vapor Recovery (EVR) amendments to its gas station vapor recovery regulations (Phase I and Phase II). In addition, CARB adopted new standards to make vapor recovery system compatible with on-board vapor recovery (ORVR) systems on motor vehicles, to reduce gasoline spillage, liquid retain in the nozzles, and pressure-related fugitive emissions. The adopted amendments also include mandatory In-Station-Diagnostics (ISD), which require electronic monitoring of vapor recovery system operation and performance.
- In December 2013, CARB revised the emission factors for Gasoline Marketing Operations at California Gasoline Dispensing Facilities.
(e) Speciation
The total organic gas emissions from the Gasoline Filling Station Fueling categories are considered all reactive organic gas(ROG). The ROG:TOG ratio is equal to 1.
6.10.3 Changes in Methodology
There are two major changes in the methodology for the current base year emissions inventory (EI) as compared to previous inventories:
- Estimates for the gasoline consumption (Annual throughput) related to these Gasoline Filling Station Storage categories were obtained from CEC.
- Emission factors were based on the revised CARB emission factors for the Gasoline Dispensing Facilities.
6.10.4 Emissions
A summary of emissions by category, county, and year are available via the associated data dashboard for this inventory publication.
6.10.5 Trends
(a) Historical Emissions/History
Emissions for these categories had been reduced due to Phase I and II vapor balance system requirements since 1975. Prior to 1990 Base Year, taxable gasoline sales for California obtained from the Board of Equalization were assumed to be distributed to all gasoline filling stations in the California. CARB estimated that Bay Area consumed 20.01% of the state total. The emissions for this category were determined according to this estimated throughput. Gasoline consumption in 2007 reached record levels. However, the gasoline consumption decreased slightly during the economic recession in 2008. In 2014, the emissions dropped significantly and have been projected to continue to decline in future years based on the revised CARB emission factors for Gasoline Dispensing Facilities.
(b) Future Projections/ Growth
Projections are based on CARB’s Emission Factor (EMFAC) model, EMFAC2021194, which includes estimates of gasoline consumption in the Bay Area. Due to the coronavirus pandemic impact on the economy, gasoline consumption dropped significantly in 2020. With the new requirements of the California Executive order 195 to phase out gasoline powered cars and passenger trucks by 2035, the GDF categories’ emissions are expected to be further reduced for forecasted emission years.
6.10.6 Uncertainties
For historical years, a majority of GDF emissions were reported under the area source categories noted in this chapter. However, starting in 2017, more information became available for individual GDFs and emissions estimates were able to be made as point source emissions. Therefore, from 2017 and on, emissions for these area and point source categories overlap and may result in the double counting emissions. This has been noted and is slated as a future inventory improvement. The gasoline consumption estimates for Solano and Sonoma counties may contribute to an increased uncertainty of the Bay Area gasoline consumption for the base year emission inventory.
6.10.7 Contact
Author: Minh Nguyen
Reviewer: Ariana Husain
Last Update: November 06, 2023
6.10.8 References & Footnotes
CARB. 2018. Miscellaneous Process Methodology, Gas Dispensing Facilities, https://ww3.arb.ca.gov/ei/areasrc/fullpdf/full_4-10_april_2018_methodology.pdf↩︎
CEC. 2021. California Annual Retail Fuel Outlet Report Results (CEC-A15), https://www.energy.ca.gov/data-reports/energy-almanac/transportation-energy/california-retail-fuel-outlet-annual-reporting↩︎
CARB. 2013. CARB Monitoring and Laboratory Division, Revised Emission Factors for Gasoline Marketing Operations at California Gasoline Dispensing Facilities, https://ww3.arb.ca.gov/vapor/gdf-emisfactor/gdfumbrella.pdf↩︎
BAAQMD. 2002. Regulation 8, Rule 7 - Gasoline Dispensing Facilities, https://www.baaqmd.gov/~/media/dotgov/files/rules/reg-8-rule-7-gasoline-dispensing-facilities/documents/rg0807.pdf?la=en&rev=55e12318cc9f47c1bd38690a14c85540↩︎
CARB. 2022. EMFAC2021 emissions inventories of on-road mobile sources in California, https://arb.ca.gov/emfac/↩︎
CA Executive order. 2020. Governor Newsom Announces California Will Phase Out Gasoline-Powered Cars & Drastically Reduce Demand for Fossil Fuel in California’s Fight Against Climate Change, https://www.gov.ca.gov/2020/09/23/governor-newsom-announces-california-will-phase-out-gasoline-powered-cars-drastically-reduce-demand-for-fossil-fuel-in-californias-fight-against-climate-change/ ↩︎