having made biodiesel and used it i feel more assured that i wont have a problem with biodiesel(granted your quality control is as good as you can achieve)

WVO is a grand idea if you have the time, distance to drive, and the initiative

biodiesel, sure it took me 2 days to make a batch and cost about 60 cents to the gallon(methanol 120$ for 55 gallons and 80$ for a 50 lbs of lye) but i know that i dont need to buy a heated tank, cut holes in my trunk. route fuel lines extra filters... all i had to do was spend 500$ on a processor and maybe 200$ on supplies when ever i needed them.