Ever since the debut of the Audi R10 in 2006, the mighty diesel-powered sports cars have been running on a gas-to-liquid (GTL) diesel fuel supplied by Shell. For the 2008 running of the 24 hours of Le Mans coming up in a few weeks, Audi and Shell will try a new blend that combines the GTL fuel with a BTL (biomass-to-liquid) fuel supplied by Choren. Choren is a German company that has been collaborating with Audi's parent company Volkswagen to develop the BTL
diesel branded as SunFuel. Like cellulosic ethanol, BTL is produced from non-food biomass like wood chips. Choren plans to have the worlds first commercial demonstration plant open in Freiberg, Germany within a year. A small percentage of BTL is being mixed into the GTL fuel for this year's race. This will be the first ever use of second-gen biofuel at Le Mans. Shell's GTL fuel is branded as V-Power and is sold at over 7,000 stations in Europe.