2/13. Julian Pettifer travels to the US to tell the story of the unlikely new champions of environmentalism among the Evangelical Right. But will they persuade the Bush administration to introduce new policies on curbing emissions of greenhouse gases? He also finds out about the growing number of big corporations using renewable energy, while filling up a truck with "BioWillie", a brand of biodiesel fuel launched by country music star, Willie Nelson. Producer Sue Ellis Repeated on Monday at 8.30pm