slight addendum to the above - I should have said "not dirty like fossil-diesel". I'd like to make the point that synthetic diesels like biodiesel are extremel

slight addendum to the above - I should have said "not dirty like fossil-diesel". I'd like to make the point that synthetic diesels like biodiesel are extremely clean in terms of particulates and is in fact one of the more interesting "bio-fuels" (although of course there are always problems with any approach that puts food in direct competition with fuel for feedstocks).