Last reviewed on 12-01-2023

Documentation of California's Greenhouse Gas Inventory (2023 Edition - Last updated on 12-1-2023)

♦ Category: Energy

IPCC: 1A3biii - Fuel Combustion Activities - Transport - Road Transportation - Heavy-duty Trucks and Buses
Sector: Transportation : On Road : Heavy-duty Vehicles : Buses

♦ Activity: Fuel combustion - Ethanol

♦ Greenhouse gas: Methane ( CH4 )

► Year 2000 —

● Greenhouse gas emission estimate —

Amount: 0.195 tonne of CH4 Emitted (4.87 tonnes CO2 Eq.)
Basis: Calculation
Calculation: [EMFAC CH4 emission] * ([Fuel sales] / [EMFAC total fuel combustion]) * [Fraction of fuel mix]
Reference: CARB (2016). Technical support document on GHG inventory methodologies for the 2000-2014 inventory. See Discussion of emissions from on-road transportation available at: https://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf

● Activity level used in calculations —

Activity: Fuel combustion = 172,916 gal of Ethanol
Basis: Calculation
Calculation: [EMFAC category fuel combustion] * ([Fuel sales] / [EMFAC total fuel combustion]) * [Fraction of fuel mix]
Reference: CARB (2016). Technical support document on GHG inventory methodologies for the 2000-2014 inventory. See Discussion of emissions from on-road transportation available at: https://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf
Reference: Not Applicable.

● Parameters and Constants used in calculations —

Parameter: EMFAC category fuel combustion = 42,853,072 gal
Reference: CARB (2021). The California Air Resources Board's Emission FACtors (EMFAC) model was used to calculate emission rates from all motor vehicles, such as passenger cars and heavy-duty trucks, operating on highways, freeways, and local roads in California. http://www.arb.ca.gov/msei/msei.htm
Parameter: EMFAC CH4 emission = 48,320,930 g (i.e. 48.32 tonnes)
Reference: CARB (2021). The California Air Resources Board's Emission FACtors (EMFAC) model was used to calculate emission rates from all motor vehicles, such as passenger cars and heavy-duty trucks, operating on highways, freeways, and local roads in California. http://www.arb.ca.gov/msei/msei.htm
Parameter: EMFAC N2O emission = 33,592,529 g (i.e. 33.59 tonnes)
Reference: CARB (2021). The California Air Resources Board's Emission FACtors (EMFAC) model was used to calculate emission rates from all motor vehicles, such as passenger cars and heavy-duty trucks, operating on highways, freeways, and local roads in California. http://www.arb.ca.gov/msei/msei.htm
Parameter: EMFAC total fuel combustion = 14,200,412,935 gal
Reference: CARB (2021). The California Air Resources Board's Emission FACtors (EMFAC) model was used to calculate emission rates from all motor vehicles, such as passenger cars and heavy-duty trucks, operating on highways, freeways, and local roads in California. http://www.arb.ca.gov/msei/msei.htm
Parameter: Fraction of fuel mix = 3.882E-03
Reference: CARB (2016). Technical support document on GHG inventory methodologies for the 2000-2014 inventory. See Discussion of emissions from on-road transportation available at: https://ww3.arb.ca.gov/cc/inventory/pubs/reports/2000_2014/ghg_inventory_00-14_technical_support_document.pdf
Parameter: Fuel sales = 14,760,642,277 gal
Reference: Covert T. (2013). Data request between CARB and Theresa Covert, California State Board of Equalization, April 2013.
Constant: Global warming potential of CH4 = 25
Reference: IPCC (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Solomon S., Qin D., Manning M., Chen Z., Marquis M., Averyt K.B., Tignor M., and Miller H.L. (eds.). http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_synthesis_report.htm

● Greenhouse gas emitted per unit activity (derived from values listed above) —

Amount: 1.13 g of CH4 per gal of Ethanol
28.2 g of CO2eq. per gal of Ethanol