I agree that despite the benifits of b-diesel we can not switch to it as a ereplacment of our fossil fuel system now. However it could be used inconjunction with other sources like hydrogen! Now wait before you shoot me down. Hydrogen is an energy storage fuel it takes more energy to make hydrogen then you get out of it think of it like the food chain the higher you go up the chain the less energy you get. However if we produced hydrogen using readily available renewable sources (solar, wind, tidal, etc.) then it to could be a fuel source a kind of liquid battery. In thus we would not have to produce the b-diesel in such huge quantities, and we would still have something to eat. This does not mean that our lifestyles can continue the way they are no matter what we do we will eventually run in to the problem of cost. Now there will always be oil but will you be able to afford it will the companies be able to afford to look for it not for much longer. We have either reached peak oil or are darn close. and thus we are on the top of a steep hill do you want to use the breaks on the way down or just hope we don't kill ourselves during the freefall.
Feel free to give me your oppinions on the subject.