Algae Biofuel May Have a Larger Carbon Footprint than Petroleum based Diesel
A study, published by Anna Stephenson of the University of Cambridge on July 29, 2010, revealed that farming algae to create an algae biofuel may actually produce four times the carbon emissions of extracting, refining, and burning petroleum based diesel. Stephenson reached these conclusions after creating a computer program to model the carbon footprint of algae biofuel production via growing algae in perspex tubes, which is the current conventional method.
When growing algae in a tube to create an algae biofuel, energy must be expended to pump the algae around so that it all receives sufficient sunlight. The carbon footprint of this water cycling is 320 g/MJ, compared to 86 g/MJ expended in the production and use of regular diesel.
Farming algae in open ponds has a carbon footprint of only 19g/MJ, but this method of algae biofuel production requires a lot more water than growing algae in tubes. It also yields less energy.
As an alternative to both algae biofuel methods, Benjamin Taylor, another University of Cambridge researcher, is working to create a system of tubes that will circulate algae using only 4% of the energy necessary for conventional tubular growth. This would make algae biofuel a more practical and efficient form of alternative energy.