Algae is a very diverse speicies, but the main type of algae being looked at for use as a fuel is microalgae, a cingle celled organism that can grow almost anywhere. Algae produces a lot of oil and fat, almost 60% of it's mass can be made up of oils! That makes it a much more efficient source of oils, like ethanol, than corn, which is currently the most common source of ethanol. The table below shows how drastic the difference between algae and other sources of biofuels is.
So how does it work? Much like most plants we are familiar with, algae uses sunlight, carbondioxide, and water to function. What makes algae unique, though, is that it needs no soil and can grow in slaty water or waste water. This opens up a lot of opportunities! Algea will not compete with food crops because it isn't used as food, it won't take up necessary farm land because it can grow places crops can't, it can provide an energy efficient way to treat waste water, and it can prevent an increase in CO2 in the atmosphere because it absorbs CO2.
The pictures below illustrate the way an algae cell produces ethanol and the algae fuel cycle.
The oils from algae can actually be refined using current oil refining processes and one company, Sapphire, has even succeded in making a fuel from algae that is chemically identical to gasoline!
Many companies are just a few years out from being able to produce algae fuels at a commercial level, which puts algae in the spotlight for the future of renewable fuels.
However, there are some draw backs that may keep algae from being a big player in energy for some time. The major drawback is cost and efficiency. Right now, a lot of research still needs to be done to make the production of fuels from algea cost and energy efficient and it can be tough to find investors for such research, though an increasing number are supporting algae research. The logistics of harvesting oils from algea on such a large scale and effective production are still in the works.
But, despite these hurdles, it may not be long before you're filling your car with green juice!
One of the field demonstration photobioreactors developed for algae feedstock production at ASU.
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