Biofuels of the future

Finding a truly renewable energy source is a task scientists the world over are faced with. Transforming plants into "biofuels" was once a great hope, but the process requires energy and so may actually contribute to global warming. France24 explored whether a new generation of biofuels could succeed where the previous one failed.
A team of scientists working on creating biofuels out of seaweed in Scotland are transforming Scotch whisky by-products into a green source of fuel.
And in the south west of France, farmers are managing to turn leftover fat from cooking duck into a fuel to power their farm equipment.