This table contains references for CH4. Please, follow the link to see references for CO2, and for N2O.
| Documentation for mobile sources | ||||||||
| CH4 | Name | Emission Factor | Base Calculation | Source | URL | Calculation (Separated) | Full Calculation | Notes |
| Direct transportation services | Gasoline Fleet | kg CH4 / Gallon | kg ch4 / gallon in year x = sum of average kg ch4 /gallons of gasoline for vehicle type weighted by proportion of vehicle type on road (1) in year x | 1) US GHG Inventory Archive, Full Annexes, tables that display "Age Distribution by Vehicle/Fuel Type for On-Road Vehicles", "vehicle miles traveled", or "fuel consumption" 2) EPA direct emissions from mobile combustion sources |
1) https://www.epa.gov/ghgemissions/us-greenhouse-gas-inventory-report-archive 2) https://www.epa.gov/sites/production/files/2016-03/documents/mobileemiss... |
average kg ch4/ gallon in given year = (age of vehicles on road in given year) [1] * kg/ch4 gallon in year x) g ch4/gallon for model year x = (kg/ch4/mile in year x) [2] * (mpg in year x) mpg in year x = vehicle miles traveled [1] / fuel consumption [2] |
The following abbreviations correspond to vehicle types: LDGV (light-duty gasoline vehicles), LDGT (light-duty gasoline trucks), HDGV (heavy-duty gasoline vehicles), LDDV (light-duty diesel vehicles), LDDT (light-duty diesel trucks), HDDV (heavy-duty diesel vehicles), and MC (motorcycles). For years 1990-1998, the age distribution from the 1998 GHG Inventory was used. |
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| Diesel Fleet | kg CH4/ Gallon | kg ch4 / gallon in year x = sum of average kg ch4 /gallons of gasoline for vehicle type weighted by proportion of vehicle type on road (1) in year x | 1) US GHG Inventory Archive, Full Annexes, tables that display "Age Distribution by Vehicle/Fuel Type for On-Road Vehicles", "vehicle miles traveled", or "fuel consumption" 2) EPA direct emissions from mobile combustion sources 3) National AVFT sheet 4) Default age distribution, moves 2014 sheet 5) Source type year sheet |
1) https://www.epa.gov/ghgemissions/us-greenhouse-gas-inventory-report-archive 2) https://www.epa.gov/sites/production/files/2016-03/documents/mobileemiss... |
average kg ch4/ gallon in given year = (age of vehicles on road in given year) [1] * kg/ch4 gallon in year x) kg ch4/gallon for model year x = (kg/ch4/mile in year x) [2] * (mpg in year x) mpg in year x = vehicle miles traveled [1] / fuel consumption [2] |
The following abbreviations correspond to vehicle types: LDGV (light-duty gasoline vehicles), LDGT (light-duty gasoline trucks), HDGV (heavy-duty gasoline vehicles), LDDV (light-duty diesel vehicles), LDDT (light-duty diesel trucks), HDDV (heavy-duty diesel vehicles), and MC (motorcycles). For years 1990-1998, the age distribution from the 1998 GHG Inventory was used. A breakdown of the US Diesel fleet by weight class from 1990-2015 is not available online, so it had to be calculated through a series of spreadsheets sent by the EPA. The only EPA spreadsheet that delineates between fuel types is the National AVFT sheet, which tells us the proportion of diesel vehicles in the fleet for different model years So in order to get the total for a given year, we have to find an age breakdown for every model year (age distribution) and get the population of vehicles that are 0, 1, 2, etc. years old for a given year (notice how the age distribution sums to 1) From these populations, we can find out how many diesel vehicles there are in the fleet by multiplying by the AVFT values This gives us totals, which we sum to find out the total number of diesel vehicles for that source type for a given year. Source type 21 represents all LDV's. Source types 31 and 32 represent all LDT's. Source types 41, 42, 43, 51, 52, 53, 54, 61, and 62 represent all HDV's |
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| Natural Gas Fleet | kg ch4 / MMBtu | [1] GREET 1.5 - Transportation Fuel-Cycle Model. Volume 2: Appendices of Data and Results. Table BI-1 (NOx emission factors). [2] U.S. EPA. Inventory of U.S. Greenhouse Emissions and Sinks: 1990 - 2014. Released April 15, 2016. Annex 3, Section 3.1, Table A-94 (energy consumption) and Table A-99 (vehicle miles traveled for alternative fuel vehicles). | https://www.anl.gov/energy-systems/publication/greet-15-transportation-f..., https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-a... | (g / GJ) * (1 kg / 1000 g) * (1 GJ / 1.055056 MMBtu) | Assumed passenger cars for emissions factors. Only included vehicle operation emissions. NOx emissions factor is an average of two near-term technologies for passenger cars: CNG bi-fuel and CNG dedicated (g/mi). Converted from g/mi to kg NOx/MMBtu using fuel economy in units MMBtu/mile. Fuel economy was calculated as the energy consumption of natural gas passenger cars divided by the vehicle miles traveled by light-duty cars (CNG ICE and CNG Bi-fuel). Used average emission factor across all years. | |||
| E85 Fleet | kg ch4 / Gallon | U.S. EPA. Inventory of U.S. Greenhouse Emissions and Sinks: 1990 - 2014. Released April 15, 2016. Annex 3, Section 3.1, Table A-93 (fuel consumption) and Table A-111 (NOx emissions) | https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-a... | "assumed to be the same as gasoline cars" | Assumed to be equal to gasoline fleet emissions factor. | |||
| B5 Fleet | kg ch4 / Gallon | U.S. EPA. Inventory of U.S. Greenhouse Emissions and Sinks: 1990 - 2014. Released April 15, 2016. Annex 3, Section 3.1, Table A-93 (fuel consumption) and Table A-111 (NOx emissions) | https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-a... | "assumed to be the same as diesel" | Assumed to be equal to diesel fleet emissions factor. | |||
| B20 Fleet | kg ch4 / Gallon | U.S. EPA. Inventory of U.S. Greenhouse Emissions and Sinks: 1990 - 2014. Released April 15, 2016. Annex 3, Section 3.1, Table A-93 (fuel consumption) and Table A-111 (NOx emissions) | https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-a... | "assumed to be the same as diesel" | Assumed to be equal to diesel fleet emissions factor. | |||
| B100 | kg ch4 / Gallon | U.S. EPA. Inventory of U.S. Greenhouse Emissions and Sinks: 1990 - 2014. Released April 15, 2016. Annex 3, Section 3.1, Table A-93 (fuel consumption) and Table A-111 (NOx emissions) | https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-a... | "assumed to be the same as diesel" | Assumed to be equal to diesel fleet emissions factor. | |||
| Hydrogen | kg ch4 / MMBtu | GREET 1.5 - Transportation Fuel-Cycle Model. Volume 2: Appendices of Data and Results. Table BII-1 (NOx emission factors). | https://www.anl.gov/energy-systems/publication/greet-15-transportation-f... | "assumed to be zero" | Vehicle operation emissions from hydrogen vehicles are 0. | |||
| Other Fleet Fuel | kg ch4 / MMBtu | n/a | n/a | n/a | Customized by users. No data entry here. | |||