Algae Biofuels Need Sewage And Coal To Be Green

Posted on 26. Jan, 2010 by Ross in New Technologies

Hailed as the greenest form of biofuels, algae-based biofuels have come under fire for being less environmentally friendly than other forms of biofuel by using more energy, water and greenhouse gas emissions to produce. However, coal power stations and sewage treatment plants could easily turn the tables to make algae biofuels the greenest solution available.

A new study from researchers at the University of Virgina claims that other biofuel sources such as switchgrass and corn are more green than algae, which rather than being carbon negative ends up releasing more greenhouse gases into the environment than is sequestered.

The report cites the fertilisers used in algae production as the main culprit. Fertilisers are mainly produced from petrochemical sources, and release nitrous oxide which is a far more potent greenhouse gas than carbon dioxide.

However, the study analysed data from pilot algae biofuel projects up to 15 years old. Such operations were intended to simply show the viability of the concept, rather than roll out an optimised solution, and the contrast to commercially-scaled biofuel systems is particularly unfair on algae biofuels, which are still in their infancy.

On top of that, algae biofuels do not need land resources to grow, preventing the need to choose between food and energy production. Algae biofuels have a higher lipid content which is better for vehicle fuel applications, and have a higher energy yield than crop-based biofuels.

The report notes that the fertiliser problem could be at least partially solved by feeding cultures of algae with waste water from sewage plants, providing nutrition for the algae whilst cleaning the untreated effluence. Other ways of improving the sequestration of algae biofuels would be to pump carbon dioxide from coal power stations into the algae tanks as another way of augmenting the feedstock with industrial by-products. Either solution makes algae biofuels far more green than crop-based solutions, and because the coal and sewage outputs provide different food sources they could also be used in combination rather than separately to make algae biofuels greener still.

Of course, none of this solves the possible problem of algae destroying the human race…

Image by Ross Tucknott