Could the "Mr. Fusion" device that turned garbage into fuel in Back to the Future be turning into reality? Well, yes, British scientists reported yesterday. The scientists said that "human waste" products like plastic bags, straw, wood and even sewage, can indeed be turned into biofuels. "This could offer enormous carbon savings and all we need is a source of renewable carbon," Jeremy Tomkinson, head of the Non-Food Crops Centre, told the Guardian. "We put it in a box and fuel comes out of the other end." Unlike in the movie, though, waste would be processed at central plants (which would cost about $600 million to set up) and then sold to consumers. The fuel itself would be cheap, and would have the added benefit of being made from materials that—prior to being burnt—had actually absorbed carbon from the atmosphere, reducing their overall environmental impact. Back in the United States, researchers at the University of Wisconsin at Madison have been busy discovering an entirely new kind of biofuel that outperforms ethanol and is made from fructose, a simple sugar commonly found in fruit. According to the scientists, fructose-based fuel stores 40 percent more energy than ethanol, and is more stable.