Synthetic fuel was supposed to rescue the combustion engine. The numbers say otherwise
Synthetic fuels promise to keep gasoline cars alive after 2035. Then you look at the numbers — and the dream falls apart.
Synthetic fuels are being sold as a lifeline for the internal combustion engine beyond 2035. It sounds wonderful — right up until you look at the numbers. And the numbers are merciless.
E-fuel production starts with renewable electricity. First, electrolysis turns water into hydrogen. Then CO2 is captured from the air and synthesised with that hydrogen into a liquid fuel. A long, multi-step chain — and every single step eats its share of energy. By the time the fuel reaches your tank, only about 40% of the original electricity is left.
Then it gets worse. A combustion engine converts roughly a third of the fuel’s energy into actual motion. The rest disappears as heat — into the air, into nothing. The end result? Your car uses about 15% of the renewable electricity it all started with. Eighty-five percent — gone along the way.
What does that mean in real life? Driving 100 km on synthetic fuel burns through roughly 150 kWh of clean electricity. A modern EV covers the same distance on 15–20 kWh. A near tenfold gap — one no future combustion engine breakthrough can close.
Price is the second blow. Experts estimate future e-fuel pricing at 4–6 euros per litre. Filling a 50-litre tank means 200–300 euros. Ready to pay that for a weekend drive?
So where does synthetic fuel actually belong? Wherever batteries still can’t go: motorsport, collector supercars, aviation, shipping. Wherever you need extreme energy density, or electrification simply isn’t feasible. For everyday passenger cars, e-fuel looks like a luxury without a future.