http://edition.cnn.com/2008/WORLD/as.../11/eco.algae/
The greenest of the green?
Algae have been touted as the greenest of all green fuels and it's not hard to see why. They are oil-rich themselves, with some strands carrying more than 50 percent oil content.
They can grow in the most hostile of regions such as deserts so don't infringe on land set aside for food crops. They don't require freshwater to flourish, and can thrive off saltwater or wastewater, making sewage farms a natural habitat.
Algae also reproduce at an astonishing rate; they are able to double in size in a matter of hours. They are amongst the fastest growing plants on Earth.
What make algae particularly useful as a feedstock is that they thrive off carbon dioxide (C02), which makes them great carbon sequesters. That also means that the other natural places to cultivate algae are power stations.
The algae can absorb as much as 75 percent of the exhaust gas, claims U.S. firm GreenFuel Technologies, using its bespoke bio-reactor. Algae doesn't just grow in the sun, contrary to previous belief. San Francisco start-up company Solazyme says it can now generate biofuels from algae grown in the dark.
The sun is replaced by sugar, essentially, which is fed to the algae, which then produces different types of oil that can be processed into a variety of fuels, suitable for cars and planes. These algae produce more oil than they would in the sun, the company claims.
Compared to other types of feedstock, algae is incredibly productive.
Most agree it can eclipse any other type of fuel crop grown today -- palm oil can yield around 6,000 liters per hectare per year (per/h/y) of fuel, for example while algae can yield more than four times that amount.