This bus runs in Bristol, UK. Similar buses also run in Oslo, Norway.

The bus numbered 2, is powered entirely by human feces and food waste, which is processed at a sewage plant to extract biomethane. As compared to diesel buses, the Bio-bus produces 20-30% less carbon dioxide, 80% fewer nitrogen oxides and is low in particulates.

Here is a patent for an electric car that may be charged using biogas.

US9365127

Source: Wikipedia