Biofuel from CO2: Too good to be true?

Pyrococcus furiosus, aka rushing fireball
Credit: Michelle Kropf/ Missouri University of Science & Technology

Too good to be true?  So far, yes.

Existing systems to do this involve growing crops to produce biomass & then converting the biomass to fuel.  Perhaps the best known is growing sugar cane & converting the sugar to alcohol, using a conventional brewing process.  Sounds attractive on the surface: take carbon dioxide from the air & turn it into biofuel.

Where this falls down is that 1 unit of food energy requires inputs of 7 units (or more) of fossil fuel energy.  Turning the food into fuel doesn't improve the equation.  Biofuel produced by this method involves a big loss of energy.  It it not a green solution.

Linked below just might be an answer.  Before giving this one the tick, many questions have to be answered, most importantly, how much carbon dioxide is emitted in producing fuel by this method?

http://www.greencarreports.com/news/1083167_biofuel-from-co2-too-good-to-be-true / energy fuel petrol photosynthesis extremophile deep ocean vent black smoker volcanic transport future fossil fuel petroleum hydrocarbon carbon dioxide CO2 greenhouse gas global warming climate change University of Georgia Biomass Magazine researchers microorganisms atmosphere air atmospheric processes plants plant life photosynthesis sunlight transform water sugars sugar /