citation please. doesn't most of the energy come from the sun?Lubricity and uncontroled crap in the fuel. Yeah I want that in my $800 injector (thats $800 per injector). Biodiesel is a pipe dream on a large scale. Second Law Efficiency studies have shown it will cost more fuel to grow the feedstock than you can produce into fuel. For a small fleet or individual it isn't bad, but on a large scale it is just something to make hippies feel good. Just like how they think fuel cells are zero emissions.