PStarr,
Fair comment. If you look at the replies made at the end of the GreenCar Congress article cited earlier, other people have made similar criticisms. Reel$$ says that the EROEI for cellulosic ethanol is 2.8 not 3.8 as claimed in the article. And there is a carbon footprint.
Nevertheless, BP has already made the commerical decision to proceed with another ethanol plant. Obviously, they think that they will make money from this new plant.
Don't know what EROEI is for algae. Do you?
[This is probably not known as yet because "Algae are high-cost/high-yield ($5-10/kg and 30 times more energy per acre than terrestrial crops) feedstocks to produce biofuels - although there is active research to reduce both capital and operating costs of production so that it is commercially viable."
http://www.nationmaster.com/encyclopedia/%0AAlgae-fuel]
Criticism is healthy. If you and others feel so inclined, you don't have to buy a car that runs on ethanol or a ethanol blend. But when fuel is short, and you have no option, wouldn't you buy an ethanol blend then?
Besides, one really ought to give secondary and tertiary biofuels a chance because they haven't been fully tested yet.
Human history becomes more and more a race between education and catastrophe. H. G. Wells.
Fatih Birol's motto: leave oil before it leaves us.