I live in Italy and we are starting to get methane gas stations. Here's a link to a site that is partially in English:
Notizie < Metanoauto.com - la comunità italiana del metano per auto
I'm no expert, and it's only been explained to me in Italian (80% comprehesion!!!!), but I think the gas is generated from livestock. You also get all sorts of tax breaks, a special license plate that allows you to drive in areas that other cars can't (a lot of towns here limit traffic in the city center).