Barcelona, Spain: The city has been exploring and implementing projects to use biomethane derived from sewage sludge to fuel its public bus fleet. The LIFE NIMBUS project is a notable initiative that has a plant to produce biomethane from wastewater sludge to power a bus, with plans for a larger-scale rollout.Linköping, Sweden: This city is a pioneer in the field. All of its urban buses run on biomethane produced from agricultural waste and sewage sludge. This has led to a significant reduction in emissions and has also extended to taxis, trucks, and other municipal vehicles.Vaasa, Finland: In 2017, the city of Vaasa introduced a fleet of new biogas-fueled buses. The biogas is produced from local household waste and wastewater at a treatment plant.Nottingham, UK: Nottingham City Transport operates a large fleet of double-decker buses that run on biomethane. This fuel is produced from waste, including household waste and wastewater.Pamplona, Spain: In 2022, Pamplona became the first city in Spain to operate a 100% renewable gas-powered urban fleet, with the biomethane coming from sewage sludge and organic waste.Flixbus (Europe-wide): The long-distance coach company Flixbus has launched biogas coaches on routes between Stockholm and Oslo and Amsterdam and Brussels. The biogas for the Amsterdam-Brussels route is sourced from municipal sewage sludge in Amsterdam., For five years, researchers at Veolia − the company responsible for water distribution in Barcelona − have been working to recover sewage sludge in order to produce biomethane, a sustainable , Spanish researchers turned the V3 bus line in Barcelona into an experimental vehicle running on pure renewable natural gas. For five years, researchers at the city's water.