Audi in recent years has been making strides to move away from fossil fuels but without abandoning the internal combustion engine and current refueling infrastructure. It’s been doing this with its research in the area of synthetic fuels and has already come up with synthetic natural gas and synthetic diesel, and now also a synthetic gasoline. Audi calls its synthetic gasoline E-Benzin, and has developed the fuel in partnership with French firm Global Bioenergies.
The process of creating E-Benzin starts off at a pilot plant in Pomacle, France where isobutene is produced, a gas that is formed from a fermentation process involving plant material, in this case corn-derived glucose. A purification process converts the isobutene into liquid form.
This liquefied isobutene is then sent to the Fraunhofer Center for Chemical-Biotechnological Processes in Leuna, Germany where researchers use hydrogen in a process that transforms the isobutene into isooctane, the key component of gasoline that can be used to power a vehicle. Isooctane is an additive currently formed from petroleum and used to improve gasoline quality.
Importantly, it could also be used as a standalone fuel. It is indeed the standard from which the octane rating has been defined. In its pure form it would be labelled Unleaded 100, as its octane rating is RON 100. The fuel can also be used in the production of plastic products. Furthermore, because the fuel contains no sulfur or benzene, it burns very cleanly. It is thus a high-grade fuel that enables engines to use high compression ratios for enhanced efficiency.
Audi will test the new fuel in the lab and in test engines. In the medium term, the company and Global Bioenergies aim to modify the process so that it requires no biomass, instead requiring just water, sunlight, CO2 and hydrogen. Audi is also producing hydrogen using electrolysis of water with electricity generated at wind farms in the North Sea.
Audi and Global Bioenergies now plan to build a demonstration plant at the Fraunhofer Center that will begin producing larger quantities in 2016.