But the oil companies own most all of the commercial bio diesel plants here.
And yes, you can make your own bio diesl, but you have to be very careful making it. Even though these engines can burn it without modification, it has to be made to the right grade standards, or else you WILL destroy the fuel injector, which are extremely expensive on these new diesel engines.
That's why an old VW diesel rabbit engine is so popular, they were much more forgiving with badly made home made diesel.
To make diesel out of rapeseed, all you need to do is squeeze it. Anyone can build a plant to do so.http://www.cogeneration.net/rapeseed_biodiesel.htm