Running on a vegetable/algae based fuel means the carbon output of my vehicle is directly offset by the crops grown to create the fuel in the first place. so assuming bio-diesel is available to you, and you place value on environmental issues it pays for itself almost immediatly.
Plus the energy to plant it, fertilize it, harvest it, process it and transport it which makes it somewhat less desirable. Which is why ethanol is a fallacy. Still needs improvement, just as hydrogen costs more to generate that the energy it provides. Food for thought. I apologize for the hijack.