Not all stationary combustion sources burn fossil fuels.
Biomass (non-fossil) fuels (e.g., forestry-derived, agriculture-derived, biomass-derived gases) may be combusted in stationary sources independently or co-fired with fossil fuels.
The emission calculation methods discussed in this document can be used to calculate CO2, CH4, and N2O emissions from combustion of these fuels.
The GHG Protocol requires that CO2 emissions from biomass combustion at stationary sources are reported as biomass CO2 emissions (in terms of total amount of biogenic CO2 emitted) and are tracked separately from fossil CO2 emissions. Biomass CO2 emissions are not included in the overall CO2-equivalent emissions inventory for organizations following this guidance. CH4 and N2O emissions from biomass are included in the overall CO2-equivalent emissions inventory.
There has been increased scientific inquiry into accounting for biomass in energy production.
TheEPA’s Science Advisory Board found that “there are circumstances in which biomass is grown, harvested and combusted in a carbon neutral fashion but carbon neutrality may not an appropriate assumption; it is a conclusion that should be reached only after considering a particular feedstock’s production and consumption cycle.
There is considerable heterogeneity in feedstock types, sources and production methods and thus net biogenic carbon emissions will vary considerably.”2 According to the GHG Protocol Corporate Standard, “consensus methods have yet to be developed under the GHG Protocol Corporate Standard for accounting of sequestered atmospheric carbon as it moves through the value chain of biomass-based industries,” though some general considerations for accounting for sequestered atmospheric carbon are discussed in Chapter 9 and Appendix B of the GHG Protocol Corporate Standard.
If an organization purchases biogas that is delivered through a shared natural gas pipeline, see Appendix A of the GHGProtocol Scope 2 Guidance for a discussion of appropriate GHG accounting for this situation.
Source: U.S. EPA Center for Corporate Climate Leadership – GHG Inventory Guidance