A Lower Carbon Aviation Fuel (LCAF) is defined in Annex 16 Vol IV as a "A fossil-based aviation fuel that meets the CORSIA Sustainability Criteria under this Volume." LCAF can serve as a complementary measure alongside Sustainable Aviation Fuels (SAF) in helping to reduce aviation greenhouse gas (GHG) lifecycle emissions. The LTAG report includes a quantification of the potential contributions from LCAF towards the ICAO long term aspirational goal for international aviation (LTAG)..
An LCAF may be certified as a CORSIA eligible fuel if it meets the CORSIA Sustainability Criteria, including a 10% reduction in lifecycle emissions compared to the aviation fuel baseline of 89 gCO2e/MJ. For example, five billion liters of LCAF at 80 gCO2e/MJ could provide the equivalent GHG emissions reduction of about one billion liters of SAF at 45 gCO2e/MJ.
A variety of technologies and processes could lead to the production of LCAF, such as:
Energy conservation measures (energy efficient design of plans, increased production efficiencies, improved efficiency monitoring)
Process gas management (flaring management, venting control, fugitive emissions detection)
Use of renewable/low carbon electricity, gas and hydrogen.
Use of carbon capture and storage (CCS)
More details on these technologies are provided in the following references:
Update on LCAF technologies (ICAO CAEP, April/2023)
Lower Carbon Aviation Fuels: contributing to the energy transition. ICAO Environmental Report 2022.
Aviation Climate Policy &Lower Carbon Aviation Fuel, ICAO Stocktaking 2019.
LCAF sustainability criteria are defined in the ICAO document "CORSIA Sustainability Criteria for CORSIA Eligible Fuels". More specifically, Chapter 3 of this document defines sustainability criteria applicable to batches of CORSIA LCAF produced on or after 1 January 2024 (e.g. after the CORSIA Pilot Phase). These LCAF sustainability criteria cover carbon emissions, environmental and socio-economical aspects.
Under CORSIA, the life cycle emissions of LCAF needs to be obtained with the use of the methodologies defined in Chapter 7 of the ICAO document "CORSIA Methodology For Calculating Actual Life Cycle Emissions Values".