Emissions factors are released each year as versions. Each year's version includes the most up to date emissions factors available. You can select which version you would like to use on the calculation sources and methods form. And remember, Tier 1 users can always customize their emissions factors on the Data Entry tab.
List of references used in the recommended version of emission factors (2019)
Table summarizing all emission factors, with links to detailed reference pages (2019)
| Version | 2017 | 2018 | 2019 | 2020 (Recommended) |
| Date released | November 2017 | April 2019 | February 2020 | January 2021 |
| Scope 1 | ||||
| Stationary combustion | On-campus stationary changes, new NOx emissions factors | Unchanged from 2017 version |
Updated data to most recent year (Carbon Contents: 2017, Heating values: 2019) Updated methodology for CH4 from Wood Chips, Wood pellets, and Grass Pellets Error corrected for Incinerated Waste (reducing CO2 EF by around 70%) |
Updated data to most recent year (Carbon Contents: 2018, Heating values: 2019) Separated out biogenic emission factors Corrected biogenic % for residual and distillate heating (from 100% to 20%) |
| Transport fuels | Unchanged from CCC, new NOx emissions factors | Unchanged from 2017 version |
Updated data to most recent year (Carbon Contents: 2017, Heating values: 2019, Average MPGs: 2016) CH4 and N2O update for gasoline and diesel vehicles (emission factors and fuel efficiency) Biogenic fuel % updated, and error corrected |
Updated data to most recent year (Carbon Contents: 2018, Heating values: 2019, Average MPGs: 2017) Updated biogenic % for E85 (from 85% to 74%) |
| Fertilizer | Unchanged from CCC and NFT | Unchanged from 2017 version | Updated to the IPCC-recommended methodology for both Organic and Synthetic Fertilizer | Unchanged from 2019 version |
| Animals | Unchanged from CCC, n/a for NFT | Unchanged from 2017 version |
Updated data to most recent year (2017) Updated methodology for Beef Cows and Poultry |
Updated data to the most recent year (2018) |
| Refrigerants & chemicals | Unchanged from CCC, n/a for NFT | Unchanged from 2017 version |
Minor error corrections |
Minor naming corrections Added the option to view results using 20-year GWPs |
| Scope 2 | ||||
| Utility consumption | eGrid 2014 report (released 2016, factors updated through 2014), Custom fuel mix changes from CCC | eGrid 2016 report (released 2018, factors updated through 2016) |
eGrid 2018 report (released Feb 2020, factors updated through 2018) Note: The emission factors used in SIMAP were not affected by the 3/9/20 eGrid revision. |
eGrid 2018 report for location-based emission factors (unchanged from 2019 version of EFs) |
| Residuals for CO2 for 2015 by NERC region. | Residual emission factors for CO2 added for 2016 by NERC region. | Residual emission factors for CO2 in 2015, 2016, and 2017 by eGrid region. Residual emission factors were previously by NERC regions. | Residual emission factors for market-based approach updated through 2018 | |
| Scope 3 | ||||
| Commuting | Unchanged from CCC, new NOx emissions factors | Unchanged from 2017 version |
Updated data to most recent year (Carbon Contents: 2017, Heating values: 2019, Average MPGs: 2016) CH4 and N2O update for gasoline and diesel vehicles (emission factors and fuel efficiency) Updated electricity mix (for light rail and commuter rail) using eGrid 2018 |
Updated data to most recent year (Carbon Contents: 2018, Heating values: 2019, Average MPGs: 2017) |
| Business travel & study abroad | Air travel CO2, new NOx emissions factors | Unchanged from 2017 version |
Updated data to most recent year (Carbon Contents: 2017, Heating values: 2019, Average MPGs: 2016) CH4 and N2O update for gasoline and diesel vehicles (emission factors and fuel efficiency) |
Updated data to most recent year (Carbon Contents: 2018, Heating values: 2019, Average MPGs: 2017) |
| Student travel to/from home | Air travel CO2, new NOx emissions factors | Unchanged from 2017 version |
Updated data to most recent year (Carbon Contents: 2017, Heating values: 2019, Average MPGs: 2016) CH4 and N2O update for gasoline and diesel vehicles (emission factors and fuel efficiency) |
Updated data to most recent year (Carbon Contents: 2018, Heating values: 2019, Average MPGs: 2017) |
| Food | New to SIMAP with GHG emissions factors. Unchanged from NFT | Unchanged from 2017 version |
No changes |
No changes |
| Paper | Unchanged from CCC. N/A for NFT | Unchanged from 2017 version |
No changes |
No changes |
| Waste & wastewater | Unchanged from CCC, new nitrogen loss factors | Unchanged from 2017 version |
No changes |
Updated waste emission factors across time using the WARM Model. Previously, the same value was used across all years. Current through 2016. |
| Sinks and offsets | ||||
| Compost | Unchanged from CCC. Nitrogen update for average compost N content | Unchanged from 2017 version | No changes | No changes |
| Non-additional sequestration | Unchanged from CCC, new for nitrogen | Unchanged from 2017 version | No changes | No changes |
| Offsets | Unchanged from CCC, new for nitrogen | Unchanged from 2017 version | No changes | No changes |
Note: This table is specific to US emissions factors. The Canadian electricity emissions factors (regional and residuals) were also updated in the 2017 and 2018 versions.
CCC = Campus Carbon Calculator, which was the Excel version of the campus carbon footprint tool
NFT = Nitrogen Footprint Tool, which was the original Excel version of the campus nitrogen footprint tool