6.6 Gasoline Truck Loading
Categories 64 and 898
6.6.1 Introduction
Categories 64 and 898 cover organic emissions (TOG and ROG) from Gasoline truck loading. Fuels are delivered by tank trucks from the fuel terminals to service stations, commercial accounts and local bulk storage plants. Loading losses are primary source of evaporative emission from truck loading. Loading losses occur as organic vapors in the empty tank are displaced to atmosphere by the liquid being loaded into the tanks. These categories account for the organic emissions associate with transfer of gasoline to trucks from racks at terminals and bulk plants.
6.6.2 Methodology
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.
Further speciation and quality assurance of emissions are performed as a part of the inventory process. The BAAQMD staff also perform a systematic crosswalk between CEPAM’s source category classification (Emission Inventory Code - EICs) and the District’s source category classification (category identification number - cat_ids), which ensures consistency in the annual emissions reporting process (CEIDARS) to California Air Resources Board. The last part of the inventory development process includes forecasting and back casting, and aggregation into sub-sectors and sectors for documentation purposes. For those years where no data is available, emissions data are backcasted to year-1990, as well as forecasted to year-2040 using either interpolation or another mathematical approach (see Trends section). Finally, emissions trends spanning from year 1990-2040 for each category and pollutant are evaluated for anomalies that are then investigated and addressed.
Categories 64 and 898, Gasoline Truck Loading categories, are considered point source categories and follow the above methodology for emissions estimates.
Truck loading emissions at bulk plants and terminals are subject to Rule 8-39 175, Gasoline Bulk and Cargo Plants and Rule 8-33, Gasoline Bulk and Cargo Terminals, respectively. The adoption in 1987 and subsequent amendments in 1994 and 2009 to both Rules 8-39 and 8-33, require reductions in emissions of precursor organic compounds from gasoline transfer operations at gasoline bulk plants (Cat #64), terminals (Cat #898), and associated delivery vehicles .
On April 15, 2009, the District amended [Rule 8-33] (Gasoline Bulk Terminals) and [Rule 8-39] (Gasoline Bulk Plants). The amendments include a requirement to minimize the release of organic compounds during maintenance and repair operations, and a reduction in the allowable backpressure in new vapor recovery system piping.
In 2020 and 2021, two of the five petroleum refineries in the Bay Area submitted permit applications to modify the facility operation to process alternative feedstocks with the intention of producing “renewable” products. Regulation 8 Rule 33 was passed on November 03, 2021. 176
These source categories report Total Organics Gas (TOG) emissions. The ROG: TOG ratio is equal to 1.
6.6.3 Changes in Methodology
No major changes in methodology were made in this version of the base year emissions inventory.
6.6.4 Emissions
A summary of emissions by category, county, and year are available via the associated data dashboard for this inventory publication.
6.6.5 Trends
(a) Historical Emissions / History
Historical emissions for point source emissions are derived from source-specific throughputs provided by the permitted facility, compiled/reported emission factors, and regulation-based control factors. This information is archived in the BAAQMD’s internal database which is queried to retrieve the data for historical and current years. Interpolation techniques to account for missing data are used when necessary, this is the case for years 1991-1992.
(b) Future Projections / Growth
Forecasting of point source emissions is done based on calculations as shown in the equation below using recently updated growth profiles and a base year of 2020. The growth profiles for the current base year inventory have been verified and updated to represent the most likely surrogate for growing emissions for a given category up to year 2040. Forecasting for point source emissions includes impact of in-place regulations, but does not include estimation of controls that will theoretically be implemented as part of future policy emission targets or proposed regulation and legislation.
\[ \text{PE} = \text{Gr} * \text{Ci} * \text{Ei} \]
\(PE\) = projected emissions of pollutant i in a future year
\(Gr\) = growth rate by economic profile of industry or population
\(Ci\) = control factor of pollutant i based on adopted rules and regulations
\(Ei\) = base year emissions of pollutant i
Projections are based on CARB’s EMFAC2021 future gasoline consumption in the Bay Area.
6.6.6 Uncertainties
The estimated emissions for categories 64 and 898 are largely based on five petroleum refineries in the Bay Area. Any uncertainty in the emissions estimates at these facilities contribute to an increased uncertainty of the point source emissions.
6.6.7 Contact
Author: Michael Nguyen
Reviewer: Ariana Husain
Last Update: November 06, 2023
6.6.8 References & Footnotes
BAAQMD. 2021. Regulation 8 Rule 39 - Gasoline Bulk Plants and Gasoline Delivery Vehicles, https://www.baaqmd.gov/~/media/dotgov/files/rules/refinery-rules-definitions/rg0839_20211103-pdf.pdf↩︎
BAAQMD. 2021. Regulation 8 Rule 33 - Gasoline Bulk Terminals and Gasoline Delivery Vehicles, https://www.baaqmd.gov/~/media/dotgov/files/rules/refinery-rules-definitions/rg0833_20211103-pdf.pdf↩︎