Taking a look at algae’s green credentials (Image: Sipa Press/Rex Features)

BUBBLING green tubes filled with algae gobbling up carbon dioxide and producing biodiesel may sound like the perfect way to make clean fuel, but it could generate nearly four times the greenhouse emissions from regular diesel.

How we farm algae is crucial to making algal biodiesel environmentally viable, says Anna Stephenson at the University of Cambridge. She has developed a computer model that calculates the carbon footprint of producing, refining and burning algal biodiesel.

Making algal biodiesel in clear tubes has a carbon footprint nearly four times that of producing diesel …