Synthetic fuels:
the complete guide to syn-fuels,
e-fuels and Power-to-Liquid

Synthetic fuels — commonly called syn-fuels, e-fuels or electrofuels — are liquid or gaseous fuels produced by combining hydrogen (H₂) with carbon dioxide (CO₂) through chemical synthesis. The resulting molecules are chemically identical to fossil petrol, diesel, kerosene, methanol or methane.

The fundamental difference from fossil fuels is the source of the carbon and hydrogen. In fossil fuels, carbon comes from ancient biological material stored underground. In synthetic fuels, carbon is captured from the atmosphere (direct air capture) or from industrial exhaust gases — and hydrogen comes from electrolysis (green hydrogen) or from natural geological sources (white hydrogen). The carbon cycle is closed: the CO₂ emitted during combustion was captured before production.

The key advantage over battery electric alternatives: synthetic fuels work in existing engines, vehicles, aircraft and ships with no modification. They can be transported through existing pipelines, stored in existing tanks, and sold through existing fuel stations. The entire energy distribution infrastructure built over the past century becomes zero-carbon without replacement.

The key challenge: cost. Today's synthetic e-fuels cost 2–5× more than their fossil equivalents — primarily because green hydrogen from electrolysis costs €3–6/kg. If natural geological hydrogen from Lorraine reaches €0.50/kg in 2028, this changes fundamentally.

The most expensive step in any PtL process is Step 2 — electrolysis. At current electricity prices, producing 1 kg of green hydrogen via electrolysis costs €3–6/kg and consumes ~55 kWh of electricity.

Natural geological hydrogen from the Lorraine deposit (FDE PTH-2, 49.6% H₂ at 2,426m, June 2026) targets €0.50/kg production cost by late 2028. If achieved, this eliminates Step 2 entirely and reduces the cost of every syn-fuel by 50–60%.

The European Commission recognises this: its July 2026 contract to Getech (€1M+) will map natural H₂ prospectivity across all 27 EU member states — identifying additional feedstock sites for future European PtL syn-fuel plants.

Fischer-Tropsch (FT-PtL) — most versatile: one process produces all liquid fuel types (diesel, kerosene, naphtha, wax). INERATEC ERA ONE is the reference commercial plant. Overall efficiency: ~44–52%.

Methanol synthesis (PtM) — simpler and more efficient for methanol specifically. Maersk's maritime supply chain relies on this route. Overall efficiency: ~55–62% for methanol output.

Co-electrolysis (SOEC) — Sunfire's solid oxide electrolyser co-electrolyses steam + CO₂ directly into syngas, eliminating the RWGS step. Highest efficiency: ~58–67%. Industrial deployments in Norway and Germany.