Power-to-Liquid

Power-to-Liquid (PtL) SAF, also called e-SAF, is produced directly from renewable hydrogen and CO2. It qualifies as a Renewable Fuel of Non-Biological Origin (RFNBO), and therefore counts toward the synthetic aviation fuel sub-mandate of ReFuelEU Aviation.

The main e-SAF route combines hydrogen and CO2 into syngas, which is converted into hydrocarbons by Fischer-Tropsch (FT) synthesis. The resulting fuel is certified as FT-SPK under ASTM D7566 Annex A1. An alternative route converts e-methanol into jet fuel (see Methanol-to-Jet).

The CO2 can be sourced from biogenic sources such as fermentation, biogas upgrading or biomass combustion, or from direct air capture (DAC).

Renewable Hydrogen can be supplied from commercially proven technologies, including alkaline, PEM and solid oxide electrolysis, with technology selection depending on project-specific process integration and operating requirements.

Because renewable electricity is a key input, this process falls under the Power to Liquid (PtL) route.

The process for PtL e-SAF production generally includes:

• CO2 recovery/capture and purification
• H2 supply, or electrolytic H2 generation, purification, compression and/or buffer storage
• Syngas generation by reverse water-gas shift (RWGS)
• Syngas conditioning and compression
• Fischer-Tropsch synthesis
• Wax hydrocracking and isomerisation
• Fractionation into SAF, renewable diesel and naphtha
• Tail gas recycle and heat recovery
• Storage and loading

DSEC has designed and built CO2 recovery and purification units at bioethanol plants, and has decades of experience in gas clean-up, heat recovery and integration, utilities and Balance of Plant (BoP). Through various biofuels and biochemical projects, DSEC has integrated hydrogen generation and compression equipment. This allows DSEC to provide critical expertise in CO2 supply and plant-wide integration around the licensed electrolysis, RWGS and Fischer-Tropsch technologies. DSEC is well placed to develop e-SAF projects integrated into bioethanol, biogas or other bio-industrial sites, where biogenic CO2 is already available.