The New York Times had a lead business article on this yesterday. Cow power is growing. http://tinyurl.com/pcef7 Here is a related article describing the growth of biomethane in Sweden. A world leader in energy independence, "Biomethane powers more than 8,000 transit buses, garbage trucks, and 10 different models of passenger cars in Sweden. The country has more than 25 biomethane production facilities and 65 filling stations" California has started a partnership with Sweden to develop bioenergy, especially biomethane. http://www.greencarcongress.com/2006/06/california_and_.html I wonder how much methane is generated by my septic tank?