Everyone has heard the algae pitch by now. The rapid-growing, single-celled buggers produce an inordinate amount of oil. Approximately 30 percent of their body mass in a natural state is lipid content and genetic engineering and selective breeding can pop it up closer to 70 percent. The whole North Sea oil field was once a giant algal bloom. Algae proponents say they will ultimately be able to get 5,000 to 10,000 gallons of oil per acre per year from algae. That's better than cellulosic ethanol where the optimistic prognosis is 2,700 gallons. A couple of thousand square miles of desert land and you could provide all of the fuel the U.S. needs, in theory. Why so greasy? Evolution, says Jonathan Wolfson, CEO of Solazyme. By producing oil, algae effectively could store food. Oil also allowed algae to float to the surface and thus generate more food through photosynthesis. Being single celled in that case helped quite a bit: untethered by roots, algae might accidentally drift toward sunlight, or survive on oil if it were mired under a rock. Solazyme says it will be in position to produce algae-based fuel that's competitively priced in two to three years. The industry, though, is going to have to go through a massive evolutionary crunch itself. There are several ways for producing algae -- bioreactors, open ponds, industrial fermenters -- as well as ways of extracting the water (when necessary) and the oil. Genetic modification or natural strains? That's an ongoing debate. To make money, several algae producers say they have to sell the meal -- the parts of the cell that aren't oil -- as pet food to make money. There are even debates over whether the algae can be milked, rather than killed, to serve your driving needs. Solix, one of the few fifty plus algae fuel companies out there that has received VC funds -- says it costs $33 a gallon to produce algae fuel right now and that's in optimal lab conditions.