FCV: Battery charge times are why they are looking at fuel cells. Run time with a FCV can be pushed to near the gasoline powered run times. Essentially being able to recharge the battery at a refueling station. People don't want to wait 30-40 minutes for their car to charge(heck they barely want to wait that long for their cell phone haha).
Biodiesel: Well when you start refining and adding agents it starts to lessen the green aspect of it. Typical thinning agents are almost as bad as the diesel they are trying to replace. Heck why not run cars on grain alcohol... er... never mind... been done.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." Thomas Jefferson