VW communications director Steve Keyes told AutoblogGreen last week that VW was not yet prepared to support B20 use in the company's new Jetta TDI Clean Diesel, despite the fact that a B20 standard was finalized in June and will be going into effect in October. Currently, the manufacturer only recommends biodiesel concentrations of up to five percent.

The report said that the new B20 standard is really aimed at commercial fuels, and that supported fuels are still not widely available. There are also concerns that the "higher bio concentrations will result in excessive ash build-up in the particulate filter and other issues," which mirrors what Mercedes has gone on record as saying about its own BlueTEC cars.

That said, at least one enterprising TDIClub reader—the proprietor of DieselGreen fuels in Austin TX—is experimenting with regular B100 use in his brand new 2009 Jetta TDI. This is not at all sanctioned by VW and could result in serious engine damage, so we're certainly not recommending you try it out. But early indications are that it's at least possible, and that engine damage would result more from a bad batch of biofuel than from, say, anything inherently wrong with the idea. If you have any experiences or know anything about B100 use, let us know in the Comments section below.