Limonene

A relatively new biofuel is called d-Limonene and it has many essential uses,
such as pest control, as a solvent and as a terpene based fuel or gas.



The wikipedia article has some insightful information:
Limonene Wiki Entry

Image Source:
buy-lemons-online.com

I hope to be able to post some more resources about this fuel here soon.
I understand it can be synthesized so that may be one way of cheaply producing
this fuel without affecting food prices or sources.

Here is a good video for those of you familiar with organic chemistry and wish
to make their own limonene extraction for experimentation:


The green method of extracting: