Liquified Natural Gas (LNG) is natural gas in its liquid form. LNG is produced by purifying natural gas and super-cooling it to -260°F to turn it into a liquid. During the process known as liquefaction, natural gas is cooled below its boiling point, removing most of the extraneous compounds found in the fuel. The remaining natural gas is primarily methane with small amounts of other hydrocarbons. One gasoline gallon equivalent (GGE) equals about 1.5 gallons of LNG.
LNG is suitable for trucks that require longer ranges because liquid is denser than gas and, therefore, more energy can be stored by volume. LNG is typically used in medium- and heavy-duty vehicles. It’s best suited for fleets with centralized fueling, such as city fleets with garbage trucks, snowplows and maintenance vehicles.
LNG must be kept at cold temperatures and is stored in double-walled, vacuum-insulated pressure vessels. These storage requirements and the relatively high production cost have limited widespread use of the fuel.