Fuelling the future

 A leader in electronic mobility, Audi is also continuing to pursue its e-fuels strategy, working to develop and refine synthetic fuels for the future.

Working on such fuels as e-gas, ‘e-benzin' (e-petrol) and e-diesel, Audi and its development partners are making great inroads into producing these fuels as a future alternative to fossil fuels.

It’s an often slow process, but Audi is making progress. In the case of synthetic Audi ‘e-benzin' (e-petrol), Audi has now achieved an important intermediate goal, together with their development partners, Global Bioenergies S.A. in Leuna (Saxony) they have produced a sufficient quantity of regeneratively produced fuel for initial engine tests for the first time.

The largest batch of e-gasoline ever produced – 60 litres – has been achieved, will allow Audi engineers examine the combustion and emission behaviour of the renewable fuel in a test engine.

“Like all Audi e-fuels, the new fuel has many advantages. It isn't dependent on crude oil, it is compatible with the existing infrastructure and it offers the prospect of a closed carbon cycle,” says Reiner Mangold, Head of Sustainable Product Development at AUDI AG. Audi ‘e-benzin' (e-petrol) is essentially a liquid iso-octane. It is currently produced from biomass in a two-step process where Global Bioenergies first produces gaseous isobutene (C4H8) in a demonstration plant. Then, in the second step, the Fraunhofer Centre for Chemical Biotechnological Processes (CBP) in Leuna uses additional hydrogen to transform it into isooctane (C8H18). The fuel is free of sulfur and benzene and is therefore especially low in pollutants when it burns.

As a high-purity synthetic fuel with very good anti-knock properties, Audi ‘e-benzin' (e-petrol) offers the possibility to further increase engine compression and thus boost efficiency. Over the medium term, the project partners aim to modify the production process so that it will not require biomass – so that, in this case, CO2 and hydrogen produced from renewable sources should be sufficient source materials.

Of course, Audi has also made great strides in the production of other synthetic fuels. Audi’s alternative fuels already offer great potential for sustainable mobility and are helping reduce CO2 emissions from combustion engines – by up to 80 percent in g-tron models, for example.

For Audi, e-fuels are more than just a subject of research in laboratories. Since 2013, Audi has been offering renewable Audi e-gas on the market, originating in part from the company’s own power-to-gas plant in Werlte (Emsland). Customers fill up their Audi g-tron model at any CNG filling station and pay the regular price for it.

Audi e-diesel is also part of the Audi e-fuels portfolio. In Dresden, Audi’s co-operation partner Sunfire operated a pilot plant for this purpose from late 2014 to October 2016. As in Werlte, green electricity supplied the energy, and water and CO2 were also used as raw materials. The end product was called Blue Crude, which was refined into Audi e‑diesel. Audi is currently planning production capacity in Laufenburg in the Swiss canton of Aargau. Together with partners Ineratec GmbH and Energiedienst Holding AG, a new pilot plant will produce around 400,000 litres of Audi e-diesel per year – and for the first time ever, the sole energy supply to be used is hydroelectric power.