Scope 5’s WRI Resource Library includes emission factors published by The Greenhouse Gas Protocol (resulting from a partnership of WRI and WBCSD). In the words of the Greenhouse Gas Protocol, their numbers are the “most widely used international accounting tool for government and business leaders to understand, quantify, and manage greenhouse gas emissions”. As such, WRI conversion factors are broadly recognized and the library is general enough to support most Greenhouse Gas emissions reporting protocols.
The WRI offers conversion factors for many activity sectors (including such specialized sectors as Lime and Cement). Scope 5’s WRI library includes the following subsets that we consider generally useful:
- Mobile Combustion
- Stationary Combustion
If there are specialized sectors that your organization would like to see added to the Scope 5 WRI library, please contact us to discuss them.
Where the Numbers Come From
The WRI sources many of their numbers from other authorities, such as the Environmental Protection Agency, the International Panel on Climate Change and the International Energy Agency. Scope 5’s WRI library is based largely on two publications from the WRI – Emissions Factors from Cross-Sector Tools (August 2012) and the updated Emissions Factors from Cross-Sector Tools (April 2014). Certain datasets in the Scope 5 library were sourced by the WRI from other sources, published by the GHG Protocol and identified on their All Tools page.
To identify the source of a specific set of emissions factors in Scope 5, please refer to the ‘Source’ for the specific conversion factor set, as illustrated in the following example:
The WRI library includes the EPA eGRID emissions factors. WRI’s 2014 updates include only a subset of the EPA’s eGrid numbers. However, in order to maximize the utility of the WRI library to Scope 5 users, we have included all eGrid updates published by the EPA through their January 2020 update.
In addition, various regions have come and gone from the EPA’s eGrid tables over the years. The April 2014 update from the EPA covers 27 regions. The WRI picked up 26 of these in their April 2014 update (omitting US Average numbers). By contrast, the eGrid section of the Scope 5 WRI library covers 36 regions. This is because we chose to include all 34 regions published by the EPA since their 2005 release, as well as the more recently published US Average and US Average (non-baseload) numbers.
For international electricity emissions factors, please see Scope 5 International Electricity Library.
A Note on Air Travel Distance Categories
The WRI provides emissions factors for three distance categories:
- Domestic (< 463 km)
- Short Haul (≥ 463 <1108 km)
- Long Haul (≥ 1108 km).
These thresholds come from the bottom of the 'Activity Data' tab of the GHG Protocol's Transport Tool:
A Note on Heating Values
For all stationary combustion resources expressed in units of energy - for which the denominator is in mmBtu (or any energy unit) - Scope 5 has chosen to use the Higher Heat Value (HHV), as opposed to the Low Heating Value (LHV), to calculate the emissions factor, beginning with the 2017 update. In GHG reporting the HHV is the more conservative value as it is always slightly higher or equivalent to the LHV, resulting in a slightly higher (or equivalent) emissions factor than would be calculated by using the LHV. The initial factors set uses LHV.
Additionally, beginning with the 2017 update, energy conversion factors for stationary combustion resources with non-energy-type units assume Higher Heat Values (HHV).
Global Warming Potentials (GWPs)
Following the Greenhouse Gas Protocol recommendation, all Scope 5 standard resource libraries use global warming potentials from the IPCC's Fifth Assessment Report (AR5) as of February 13, 2017.
The WRI’s April 2014 publication incorporated multiple updates to electricity conversion factors, but none to mobile and stationary combustion conversion factors. Scope 5’s conversion factors are current through WRI’s 2014 update.
Scope 5 cannot guarantee that by using the Scope 5 WRI Resource Library users will produce a report that is fully compliant with their verification agency. We recommend working with your verifier and/or with a sustainability consultant well versed in GHG emissions reporting to be sure that your report will be fully compliant with the protocol under which you are reporting. Scope 5 can provide customized resource libraries on a case-by-case basis.