It goes without saying that public transport systems around the world are moving to greener forms of power. Buses in South Korea and the UK, for example, are being powered from electricity from underneath the road surface. Not only is the fuel for the Bio-Bus said to produce fewer emissions than traditional diesel engines, but it is also locally sourced.
"Gas-powered vehicles have an important role to play in improving air quality in UK cities, but the Bio-Bus goes further than that and is actually powered by people living in the local area, including quite possibly those on the bus itself," says Geneco general manager Mohammed Saddiq. "Using biomethane in this way not only provides a sustainable fuel, but also reduces our reliance on traditional fossil fuels."
The biomethane on which the bus runs is produced at Bristol Sewage Treatment Works. Around 75 million cu m (2,650 million cu ft) of sewage waste and 35,000 tonnes (38,600 tons) of food waste are processed using a technique called anaerobic digestion. This uses microorganisms to break down the waste, producing 17 million cu m (600 million cu ft) of biomethane a year.
According to Geneco, the Bio-Bus has a range of 300 km (186 mi) on a full tank of gas. To put it another way, it could transport people the whole length of Great Britain on the waste generated from one busload of passengers in a year.
"The bus clearly shows that human poo and our waste food are valuable resources," says chief executive of the Anaerobic Digestion & Bioresources Association Charlotte Morton. "Food which is unsuitable for human consumption should be separately collected and recycled through anaerobic digestion into green gas and biofertilisers, not wasted in landfill sites or incinerators."
The Bio-Bus went into operation in Bristol for the first time last week. Geneco says it's the first company in the UK to run buses on waste and sewage-generated gas.