In Resolution A39-3, the ICAO Assembly requested the Council to develop a methodology to ensure that an aircraft operator's offsetting requirements under CORSIA can be reduced through the use of sustainable aviation fuels. Following up on this request, ICAO has developed a methodology that allows operators to obtain the life cycle emissions value of a specific SAF, in order to claim emission reductions from the use of SAF in CORSIA.
Under this methodology, the amount of emissions reductions generated by the use of SAF depends on its life cycle emissions value, expressed in terms of grams of CO2 equivalent per megajoule (gCO2e/MJ). This life cycle emission value is composed of two main elements:
1) Core Life Cycle Assessment (LCA) emissions, which include the emissions associated with: feedstock cultivation, feedstock harvesting, collection and recovery, feedstock processing and extraction, feedstock transportation to processing and fuel production facilities, feedstock to fuel conversion processes, fuel transportation and distribution, and fuel combustion in an aircraft engine, and
2) Induced land-use change (ILUC) emissions – CORSIA Eligible Fuel production may require some additional land to be used, and generate land use change GHG emissions. These could occur where the new CORSIA Eligible Fuel production is taking place (direct land use change) but also in other locations due to the displacement of crops (or animals) for which the land was previously used (indirect land use change). ILUC emissions assessment accounts for these different effects, by evaluating greenhouse gas released from conversion of natural vegetation (forest, other natural land), soil organic carbon, oxidation of peatlands, and sequestered biomass.
The total life cycle emission value for a given SAF is the sum of core LCA emission and the ILUC emission. There are two ways of obtaining the life cycle emission value of a SAF in CORSIA: