Hate to bust the collective bubble here, but...

As far as replacing a significant fraction of the fossil fuel energy we use, biodiesel, ethanol etc are complete fantasy. It simply doesnt scale up. Even if all arable soil on the planet were used to grow corn for fuel(which it would have to be), what would we eat? We already have serious topsoil degradation problems all over the planet, along with the fact that we are running out of fresh water.

It is important to understand the density of energy stored in fossil fuels...Nothing else comes close. We have burned through about 100million years worth of stored solar energy in a hundred years or so...Its kinda scary really.