Audi e-diesel: the fuel of the future

The launch took only four months of work for Audi. The research facilities the brand has in Dresden already produce the first batch of synthetic diesel fuel, and Germany’s Federal Minister of Education and Research has just tested the first five litres of fuel in her official vehicle.

To produce Audi e-diesel fuel, the company of the four rings has carried out a series of strategic partnerships to ensure the optimised use of renewable and clean raw materials. The technology corporation Sunfire is in charge of running the plant in Dresden, which is based on the ‘power to liquid’ principle (use of ecological materials).

In addition to water, part of the carbon dioxide needed to make the fuel is supplied by biogas facilities, while the vast majority is extracted through direct capture from the ambient air, a technology from Climeworks, another of Audi’s partners.

The Audi e-diesel production process involves heating water to split it into hydrogen and oxygen through high-temperature electrolysis, at around 800 degrees Celsius. The hydrogen is then converted, with CO2, into a liquid, a long-chain hydrocarbon liquid known as blue crude. Much like petroleum, this blue crude can be refined to obtain synthetic diesel.

As an advantage, the synthetic fuel contains no sulphur or aromatic hydrocarbons, while its cetane number is high, so it is highly flammable, and it can be blended with conventional diesel or used on its own. In addition, Audi already produces its petrol counterpart, Audi e-ethanol (synthetic methane), with which the Audi A3 Sportback g-tron can be fuelled.