What Are E-Fuels and Can Combustion Engine Cars Run Cleanly on Them?

As part of the European Union’s ambitious road map to becoming climate neutral, known as the Green Deal, carmakers are required to reach a zero-emissions target by 2035. New cars or vans registered by that date cannot emit any carbon dioxide when driven, according to the plan. That would effectively ban the sale of new cars that run on gasoline or diesel in the EU. Germany, home to Volkswagen AG, Mercedes-Benz Group and other major automakers, has been threatening to throw a wrench in the works unless it gets exemptions for cars with combustion engines that run on something called climate-neutral synthetic fuels, or e-fuels — something the bloc has yet to definitively address.

Electricity-based fuels, also called synthetic fuels, have the same basic chemical structure as conventional fuels used in internal-combustion engines. While fossil fuels like petroleum produce planet-warming CO2 during the extraction and refining processes, e-fuels use electricity from renewable sources to split hydrogen from water, then blend the hydrogen with carbon dioxide from the air. The result is a liquid or gas with hydrocarbon chains that are similar to gasoline, diesel or methane.