The best dishes always contain 30 per cent fat minimum. This doesn't merely ensure a level of hearty satisfaction ( Windows 7 Whopper anybody?), it also means the leftovers contain plenty of the greasy good stuff, which can be cleverly harvested and metamorphosed into biodiesel. The technology behind this process has been around for a while, but now British firm Greenergy claims it is ramping up commercial production. The firm's CEO reckons each of his new £50million ($80million) biodiesel plants will digest a sufficient volume of waste pies, fries and taramasalata to "fill out a cruise ship every year". Mmmm, pie.