Heavy-duty liquefied natural gas (LNG) vehicles work much like gasoline-powered vehicles with a spark-ignited internal combustion engine. The natural gas is super-cooled and cryogenically stored in liquid form, usually in a tank on the side of the truck. LNG is typically a more expensive option than compressed natural gas (CNG) and is most often used in heavy-duty vehicles to meet longer range requirements. Because it is a liquid, the energy density of LNG is greater than CNG, so more fuel can be stored on board the vehicle. This makes LNG well suited for Class 7 and 8 trucks traveling greater distances.
