eFuels

eFuels are fuels produced from electricity, usually renewable, that are synthesized with captured carbon dioxide or other carbon sources to form liquid or gaseous hydrocarbons and alcohols. They are designed to replace conventional fossil fuels in sectors where direct electrification is difficult, such as aviation, shipping, and heavy road transport. eFuels are intended to be compatible with existing engines, storage, and distribution infrastructure.

The main production pathways are power-to-liquid (PtL) and power-to-gas (PtG). PtL combines hydrogen produced by electrolysis with carbon dioxide captured from direct air or industrial sources to create liquids such as e-diesel, e-kerosene, and e-gasoline via synthesis processes like Fischer-Tropsch. PtG converts electricity and CO2 into synthetic methane (e-methane) or hydrogen, which can be used directly or blended with conventional fuels. CO2 sources can include direct air capture or captured exhaust from industry.

The climate impact of eFuels depends on the carbon intensity of the electricity and the CO2 source used. When powered by renewable energy and incorporating captured CO2, life-cycle emissions can be substantially lower than those of fossil fuels; if driven by fossil electricity, the benefits are diminished. Energy efficiency is generally lower for eFuels than for direct electrification due to losses in electrolysis and synthesis, making eFuels more expensive and less efficient in many cases.

Applications and challenges include use in aviation, shipping, and other hard-to-electrify sectors. Advantages include leveraging existing engines and fuel logistics, while challenges involve high production costs, the need for abundant clean electricity and CO2 supply, and the development of regulatory frameworks and certification schemes to ensure sustainability and track emissions.