Just wanted to provide an FYI on "biodiesel." Of course, this term can apply to variety of different things -- I'm a big fan of burning "preowned" products like veggie oil. However, the "biodiesel" available at gas stations is not "bio" or "green" at all. So if you are buying it thinking you are doing the world a favour, run, RUN AWAY.

A huge part of the biodiesel production process is palm oil. One of our primary sources of palm oil are plantations in South America, where rainforest is clearcut in massive swaths to plant palm monocultures. Not only do you lose the important services of the native forest (wildlife habitat, carbon absorption, flood abatement, temperature moderation, etc), but you have replaced it with a plant monoculture -- very susceptible to disease or other problems as well as almost completely devoid of habitat and relatively speaking, almost useless at sequestering carbon.