Yeah, just like ethanol right?
Oh wait, there’s that minor problem that to make a real dent in our foreign oil dependance we’d need to convert almost all of our farm land that we’re using for FOOD into farm land for FUEL.
The short short version for people who can’t seem to grasp the big picture: Grease, great for a few cheap people with a restaurant hookup to get really cheap fuel. Terrible as a serious large scale energy source.