Times (UK): At first sight, biofuels are hugely exciting. They seem to offer a way to wean transport systems off oil. The city of Curitiba in Brazil, for example, has been famously running on sugar cane for years. The dream of a cleaner world, running on plant-power, is deeply attractive. But the current generation of biofuels cannot save the planet. In individual cities and towns, they can make a difference. But at any scale, the dream dwindles. The picture is complicated because there …