Boeing backs UK’s Firefly on sewage-based SAF

Firefly uses a process called hydrothermal liquefaction (HTL) to convert sewage into SAF, with HTL’s combination of high heat and pressure producing biocrude oil and biochar. While biochar can be useful as both a fertiliser and a medium for capturing CO2, the biocrude can be further processed into fuels, including SAF. According to the consortium, SAF produced in this manner reduces lifecycle CO2 emissions by more than 90 per cent compared to traditional jet fuel.

“SAF offers the greatest opportunity to decarbonise aviation, and the industry’s collective challenge of bringing it to scale globally requires new sustainable pathways,” Brian Moran, Boeing’s chief sustainability officer, said in a statement. “Clear Sky combines many years of investment expertise with knowledge on aviation’s decarbonisation challenges. Firefly’s technology holds transformative potential as the SAF feedstock, sewage waste, is accessible in all regions of the globe.”

Figures presented by the consortium state that SAF currently represents just 0.1 per cent of global jet fuel use. The UK has a pending mandate to achieve 10 per cent SAF in its jet fuel mix by 2030. However, this will require 1.2 million tonnes of SAF by 2030, increasing to seven million tonnes by 2050, according to consultancy ICF’s UK Net Zero Carbon Roadmap. Scaling up production to these levels presents a huge engineering and logistical challenge.