Is the industry-average emissions factor adjusted for the production of SAF?
The industry-average emissions factor for aviation fuel is not automatically adjusted to account for the production and use of Sustainable Aviation Fuel (SAF) unless there is a specific framework or mechanism in place to include SAF's lifecycle emissions reductions. Here's how it works and whether a residual mix is needed:
1. Industry-Average Emissions Factor and SAF
The industry-average emissions factor for aviation typically reflects the lifecycle greenhouse gas (GHG) emissions of conventional fossil jet fuel. This factor is used in most Scope 3 reporting for emissions from air travel.
When SAF is introduced, its lower lifecycle emissions are not automatically reflected in the industry-average emissions factor unless SAF's adoption becomes widespread and systematically included in emissions calculations across the industry.
If SAF use remains limited, a mechanism such as SAF-specific accounting (e.g., SAF certificates) is necessary to claim the reduced emissions.
2. Residual Mix in the GHG Protocol Scope 2 Framework
In the GHG Protocol Scope 2 framework, a residual mix is a calculated grid-average emissions factor representing the remaining untracked electricity attributes in a region after renewable energy claims are accounted for.
The residual mix ensures that double counting does not occur when companies make renewable energy claims via instruments like Renewable Energy Certificates (RECs).
3. Residual Mix for SAF in Aviation
In the context of SAF, a residual mix could be useful if SAF claims are made via a book-and-claim system similar to RECs. Here's how this might work:
SAF Claims via Certificates: Companies purchasing SAF certificates (SAFc) claim the lower lifecycle emissions for their flights.
Conventional Fuel in Actual Flights: Flights not covered by SAFc claims would still use the industry-average emissions factor for fossil jet fuel.
A residual mix emissions factor would be calculated for flights that cannot or do not use SAF, ensuring that double counting of SAF's benefits does not occur.
4. Current Practice and Recommendations
At present, the aviation industry typically does not have a formal residual mix for SAF. Instead:
SAF use is tracked and claimed through SAF certificates or direct use agreements.
The environmental benefits of SAF are decoupled from the physical fuel via the book-and-claim system.
For transparency and consistency, the adoption of a residual mix approach for aviation emissions would be beneficial if SAF adoption increases, especially in contexts where the book-and-claim system becomes widely used.
Conclusion
Yes, a residual mix may eventually be needed for aviation if SAF adoption scales and the book-and-claim system becomes more prevalent. This would mirror the GHG Protocol Scope 2 framework and ensure no double counting of SAF's environmental attributes while adjusting the emissions factors for flights not covered by SAF claims.
For now, SAF claims are typically managed separately through SAF certificates without adjusting the industry-average emissions factor.
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