My story today on algae being used as a biofuel briefly went over why it is better on the environment than oil, but did not go into much detail. Here is a more thorough explanation:
Just like with petroleum, the burning of algae-based oil produces greenhouse emissions. However, when oil is pumped from the ground and burned, new CO2 is released into the atmosphere. Algae, on the other hand, needs to take CO2 from the air in order to grow. So the net effect is that no new CO2 enters the system when algae is burned.
And it can be argued that the net effect is better than zero. It is possible, for example, for CO2 emissions from a power plant to be pumped directly into an algae farm.
Another reason environmentalists favor algae is that it is a far more efficient source of biofuels than corn or cellulosic sources like switch grass and soybeans.
Researchers estimate that an acre of algae could produce between 5,000 and 15,000 gallons of fuel annually. An acre of soybeans, meanwhile, would only produce 50 to 75 gallons per year. And algae can be grown just about anywhere, thereby not causing farmland that could be used for food to be used for fuel.