AVIATION AND E-SAF
E-SAF: a drop-in replacement for fossil jet fuel
Drop-in e-SAF fuels are the leading solution to decarbonise the aviation sector. HYRO develops power-to-liquid e-SAF facilities which produce e-SAF from renewable electricity and recycled CO₂.
The leading solution for low carbon aviation
Aviation consumes over 280 million tonnes of jet fuel annually. Battery electric and hydrogen fuel cell propulsion are not currently viable for long haul aviation.
Aviation infrastructure – aircraft, engines, pipelines, refuelling equipment – is built around liquid hydrocarbon fuel. E-SAF is a low-carbon replacement for fossil aviation fuels which does not require significant changes to existing infrastructure.
What e-SAF is and how it is produced
Sustainable aviation fuel (SAF) is a broad category covering low-carbon aviation fuels produced from non-fossil feedstocks. Today, most SAF is produced using biogenic feedstocks (waste fats and agricultural residues) which are constrained by feedstock availability and sustainability requirements.
E-SAF, also known as Power-to-Liquid (PtL) SAF or e-kerosene, is produced by combining green hydrogen with captured CO₂ in a synthesis reactor. Using recycled/biogenic CO₂ allows the fuel to further reduce lifecycle carbon emissions. E-SAF is chemically identical to fossil-based jet fuel.
Renewable naphtha and diesel are produced as co-products in the e-SAF production process. Renewable naphtha can either be blended in petrol for transport applications or used to decarbonise steam crackers in the chemical industry. Renewable diesel is used as a drop-in replacement for diesel transport fuels.
The UK SAF Mandate
The UK Government introduced a SAF Mandate in January 2025, requiring aviation fuel suppliers to blend increasing proportions of sustainable aviation fuel into jet fuel supplied at UK airports. Within the mandate, there is a Power-to-Liquid (PtL) sub-mandate that applies to e-SAF specifically.
This sub-mandate creates a demand signal for e-SAF in the UK – crucial to ensuring the continued development of local e-SAF production facilities.
By developing a national SAF industry, the UK SAF Mandate creates local resilience of supply and develops the UK’s clean tech industry and IP.
UK SAF Mandate — PtL SAF obligations
2028: 0.2% of total jet fuel supply must be PtL e-SAF
2030: 0.5% PtL e-SAF obligation
2040: 3.5% PtL e-SAF obligation
How HYRO helps
HYRO is working with partners to develop one of the UK’s first e-SAF projects, leading the UK’s e-SAF industry and contributing to the UK’s PtL SAF targets.
Our projects are UK-based, serving UK fuel supply obligations and contributing to UK energy resilience. Further details to be announced.
Interested in e-SAF offtake or in partnering on project development? Get in touch.