Biodiesel truly is the magical wonder-fuel. The *only* downside I know of is the higher gel point in cold weather, but that's not really an issue if you're running it blended with standard diesel.
Ford, like all manufacturers, doesn't want to *recommend* any fuel, so they play CYA games about biodiesel. Currently they're saying no more than 5% blend (B5) if you want to keep your warranty. Because I'm still running around with 7 C94 injectors I'm not doing *anything* that would risk my warranty, regardless of how unjustified a stance they're taking on biodiesel. So the '03 truck will have to wait another 60K miles before I'll run bio in it. But the '97 F250HD and the '82 M-B 300SD just eat the stuff up. They run quieter, smoother, and the exhaust smells nicer.
The '97 has suffered no loss of power on up to 70% blend. The M-B seemed to be down on power when I was running 100% blend, but I was also having problems with the wastgate vacuum line at the same time, so I need to sort that out next spring, when it warms up and I can run 100% biodiesel again.
I was buying commercial B100 for $3 a gallon and supposedly it's gone up since then. For my 13 year old's science fair project, we made some of our own! If you get the right used oil, it's dead simple. We had trouble with the gacky used fryer grease from a local restaurant, but easily made some from the used turkey frying oil a neighbor gave us after Thanksgiving.
don't understand why it is so expensive. Seems if they would lower the price, they could make a real dent in the petro diesel market.
Chicken and egg problem. It's unfathomable that it costs less to drag crude oil over from the middle east and crack it, than to grow and squish some soybeans and do a simple catalytic reaction on it, but that's a fact while the volume of petro is so amazingly high, and the volume of bio is so amazingly low. The road and excise taxes are of course the same on both, so we're just talking about the base portion. If someone makes the base portion out of "free" used grease instead of new virgin soybean oil, it could become cost-competetive. I think a place in Hawaii is doing that. (And of course all the homebrewers do that.) And the pending Energy bill with its 20 cents excise tax break for B20 might be the push required to get the momentum going on this.
If you get really serious about homebrewing, you could check these guys out: