What could be more renewable, local and green than biogas made from sewage? The new Bio-Bus that rides through Bristol successfully showcases the feasibility of harnessing energy from waste. The city’s vision is to wean the fleet off fossil fuels, while reducing greenhouse gas emissions and particle pollution. Residents hope that Bristol, which is about to become the official European Green Capital 2015, will follow in the footsteps of Oslo. The Norwegian capital has 100 biomethane buses riding in its streets.