One of the most comprehensive fule lifecycle inventories is the one done by USDA and DOE in 1998  (http://www.biodiesel.org/resources/reportsdatabase/reports/gen/19980501_gen-339.pdf).  We have known for over a decade that biodiesel is a much better alternative to diesel fuel. Those facts have been lost in the diversion created from the artificial food vs. fuel campaign.  The propaganda spread by the Grocery Manufacturers Association was a simple message that made sense to the masses.  The problem is, it is not true.  Too many people lose sight of the fact that soybeans are grown for protein meal, the oil is a byproduct, and we use less than 15% of that byproduct to make biodiesel.  The discussion on indirect land use is also misguided, because it overlooks the fact that biodiesel feedstocks are all coproducts of food production.  Farmers won’t raise additional cows so they can sell the fat for biodiesel production, likewise they won’t plant soybeans only to sell a small portion of the plant.  

We need renewable liquid fuel to power school buses, fire trucks, ambulances, and farm tractors.  Try to grow and distribute food for 6 billion people without sustainable liquid fuels, and then you have the proper context for a food vs. fuel debate. Biodiesel is the most sustainable fuel we currently have in commercial production.  There is a legitimate need for more feedstocks so we can displace more petroleum.  Too much of the talk about sustainability from misinformed stakeholders seeks to reduce the amount of feedstock available for biodiesel, which is the exact opposite direction we must move.  The US biodiesel industry has set a goal to displace 5% of US diesel demand.  We can do that with existing feedstocks with no indirect effects on land use change or food prices.  To grow beyond that we need investment in additional feedstocks, and we are getting that.  Because we have 175 production facilities across the country with 2.5 billion gallons of production capacity, we are signaling to investors and researchers working on algae and other breakthroughs that the US is committed to fossil fuel alternatives.  The current industry would shrink if we stopped using certain feedstocks, as some advocate, and we would lose progress toward energy independence.  Our current Biofuels should not be thought of as a bridge to more advanced fuels, but as a foundation for a growing renewable fuels industry.