[thejeff]

Actually thejeff will say he doesn't have a clue how or if the chemical composition of oil and TDP fuel differs.

He will also say that it's more than a semantic quibble though, since both the environmental and geopolitical consequences of the two are so different. (Not to mention the whole "fossil" part of fossil fuels.) I've never heard any refer to any kind of biofuel as a "fossil fuel" before.

Geopolitically the problem changes from paying vast sums of money to potentially unfriendly countries and propping up their dictators with oil wealth and guns to try to buy stability to just using cropland to grow fuel crops (or turkeys, but turkeys are far too inefficient to work on a large scale) instead of food.

Environmentally it's a lot better. Energy input comes from the sun to grow the crops. Any carbon released in burning the fuel is only the carbon that was absorbed in growing. In theory, especially if they can get switchgrass or something similar working, little fertilizer should be needed and land can be used that's not very good for food crops.