Algae

One of my favorite ways to make biofuel that also sinks carbon, makes oxygen, and can clean water: Algae.

Thanks to Jojo for sending me this link on CNN no less about a new kind of vertical algae farm that increases the amount of surface area per acre tremendously! Keep it up Algae farmers!

For more information on Algae as a source for bio-fuel (specifically bio-diesel) check here. Worth of note in the article is an amazing bit about how different strains of algae can be selected to produce different types or grades of fuel. For example you can have a simple bio-diesel strain, and a jet fuel strain... i wonder when the Rocket Fuel strain will be discovered! Imagine this if you will...

A giant ship traveling the solar system with a huge array of Algae farms constantly growing and generating propellant, you'd just have to refuel on comet water every now and then or maybe swoop by Saturn or Jupiter to swallow up some ice from one of their moons.