Biodiesel
The link below is to an interesting article reporting on the discovery of a way to possibly transform CO2 in the atmosphere into biofuel.
For more visit:
http://scitechdaily.com/discovery-may-lead-to-the-creation-of-biofuel-from-co2-in-the-atmosphere/
The following link is to an article about producing ethanol from seaweed, thereby reducing the need for terrestrial biofuel crops.
For more visit:
http://news.mongabay.com/2012/0120-kelp_power.html