Natural gas vehicle (NGV) is an internal combustion engine vehicle (ICEV) that is fueled with compressed natural gas (CNG) or liquefied natural gas (LNG). To power these vehicles, natural gas which consists mainly of methane (CH4) is burned with the help of oxygen from the air. As a result, NGV vehicles mostly emit only carbon dioxide and water vapour.
Natural gas mostly comes from non-renewable sources but it can also be produced from renewable sources (e.g., through anaerobic digestion of organic material). It emits less pollution than petrol and it usually costs less for the end consumer. The advantage over hydrogen as a fuel is that it can be distributed over already existing pipelines. The biggest challenge of natural gas is storing it. CNG must be stored in highly pressurised cylinders and LNG must be stored at −162 °C (−260 °F).
NGVs can either run on only natural gas or on both petrol and natural gas. All petrol-fueled vehicles can be converted into NGVs. This means installing additional equipment to the vehicle which includes a rather large cylinder for storing natural gas onboard. The size of the cylinders is one of the reasons why NGVs are mostly buses and trucks. In addition, NGVs can be passenger cars, motorcycles, ships, and aircrafts. Several car manufacturers sell commercial vehicles that use both natural gas and petrol for fuel. For example, Škoda Octavia G-TEC and Audi A5 Sportback g-tron.