Cellulosic Ethanol versus Biodiesel

When I was first introduced to Biofuel it was laid out in a plan for communities to generate ethanol from grass clippings (albeit some fancy grass). I loved the idea, communities processing their own waste into fuel. However, as companies have tried to scale up production, bioethanol has lost its luster. As a fuel source it has less energy than gasoline and production from food sources (corn) requires the use of gasoline, water, fertilizer and other inputs that lower the energetic profit, as well as purported environmental benefits. There have also been some embarrassing articles published noting that the dubious energy benefit is just a big farming subsidy scam. It could work, in theory, but we aren't there yet with the efficiency.

To make alchohol based technology a real option, one must look up the energetic food chain at larger hydrocarbons like butanol. And the big issue of competing with food crops? Chew up some waste products, like corn stover, with cellulytic bacteria and then use that sugar as an input for higher alchohol fermentation. Interestingly, the Soviet Union did a lot of research into making Acetone/Butanol/Ethanol fermentation from agricultural waste. ABE has been historically used in gunpowder and cordite manufactuing. BP has invested in cellulosic based butanolic fermentation.

Biodiesel is manufactured by a different process and uses oil as the initial energy source. People have been running cars on spent fry oil for years because the chemistry is so simple you can do it in your backyard. However, as we found out not too long ago, the push for fuel can have a negative effect when it comes at the expense of food. However, if one were able to convert non-arable land into producing oils neccessary for biodiesel, perhaps using algal culture, they would have a real winner for both environmental, economics and with some protection for food rights. Exxon-Mobil has backed Craig Venter's Sythetic Genomics in producing algal derived biodiesel.

Both technologies have great potential and I will be following closely at their development by the Big Energy as well as the little guys like Mascoma.