Prometheus Energy - a grand-sounding name for a company that deals in waste gas from trash - has just started producing LNG from natural gas emanating from the Bowerman Landfill in California, which will be used to operate public transportation vehicles in Orange County, California. This is a big site - just take a look at these pictures. Landfill gas by the way typically peaks in output over the first 5 years, after which it goes into the "exponential decay phase".

There is a view that biomethane has much more potential than bioethanol or biodiesel. As I remarked here before, I like the low-tech approach to Prometheus; get the lowest cost methane possible and turn it into fuel. Some people find landfill intrinsically wrong, but I think they are wrong. You can only go so far with recycling and the other alternative, incineration, is much less desirable.