Wessx Water, a water supply and sewerage utility company in Somerset, UK has launched a modified Volkswagen Beetle car, christened Bio-Bug, to run on methane gas produced from human waste. The gas is produced using the process of anaerobic digestion in which bugs break down bio-degradable material (in this case human waste) in the absence of oxygen to produce the gas. Carbon dioxide is then removed from the methane to improve its quality and make it fit to power the car?s engine. According to the company?s calculations, waste produced from about 70 homes in Bristol is enough to power the vehicle for one year, assuming it runs 10,000 miles a year. The Volkswagen Beetle is designed to run on both petrol and bio-methane. The vehicle is started by using unleaded petrol, and once the engine attains the right temperature, it switches automatically to methane. In case there is no methane, the engine reverts to petrol. Another city experimenting with bio-methane produced from human waste is Oslo, Norway?s capital. The city is converting 80 municipal buses to run on bio-methane derived from human waste as it seeks to cut carbon dioxide emissions and meet Norway?s ambitious plan of being carbon-neutral by 2050.