Chris, the macadamia nut tree is my choice for biofuel. The yields are quite high and the tree is a PERENNIAL. There is no cultivation, there is minimal input to harvest (you don't pick 'em, the nuts fall on the ground).

If the oil was converted to biodiesel, then the crushed meal and the resulting glycerin could be utilised to provide a high protein, high energy food bar. The nut casings go back into compost, and the shell hulls could be used for energy for the biodiesel process (the ash then returning to the soil). The tree roots bring nutrients up from deep in the ground and provide nutrients for the top soil.

If every town council mandated macadmia nut trees in the parks, landscape mediums, school yards and other areas, there would be many nuts to be harvested for the use of a local council crushing plant. The council could provide young trees, at cost, to people who wanted to plant them in their yards. People on the economic fringe could make a few dollars by collecting the nuts and selling them to the council. Perhaps the council would then be free enough from the Canberra Clowns to have enough biodiesel to provide some essential services.

I see hope for the future, I just don't see a lot of interest about that future. A macadamia nut tree takes 5-7 years before it produces nuts. Unfortunately, most people won't do anything until TSHTF.