Stagecoach is testing the UK’s first Bio-buses, which run on 100% biodiesel. The bio-fuel is manufactured by Argent Energy from used cooking oil and other food industry by-products, which are from sustainable sources that do not involve the destruction of natural habitats or compete with the human food chain. The environmental project also allows customers to exchange used cooking oil for discounted bus travel. Since the initiative was launched in October 2007, it has cut C02 emissions from the buses by 80%, saving 550 tonnes of carbon, and more than 21 tonnes of used cooking oil has been recycled.