Volkswagen offers cars that run on natural gas under the “EcoFuel” label. Compared with a conventional petrol engine, the EcoFuel power plant running in natural gas mode produces around 80 percent less carbon monoxide and around 80 percent less nitrous oxides. CO2 emissions are reduced by 23 percent and are below 129 g/km. Moreover, natural gas is currently the cheapest fuel on the market, because the gas price will enjoy tax relief until 2018.