LNG Basics
LNG is a clear, colourless and non-toxic liquid which forms when natural gas is cooled to -162ºC (-260ºF). The cooling process shrinks the volume of the gas 600 times, making it easier and safer to store and ship. In its liquid state, LNG will not ignite. LNG typically contains more than 90% methane and small amounts of ethane, propane, butane and some heavier alkanes. Of course natural gas vapors are flammable and present safety hazards that must be managed, but these hazards are substantially less than for gasoline, diesel and other liquid fuels.When LNG reaches its destination, it is turned back into a gas at regasification plants. It is then piped to homes, businesses and industries where it is burnt for heat or to generate electricity. LNG is now also emerging as a cost-competitive and cleaner transport fuel, especially for shipping and heavy-duty road transport.
For large-volume ocean transport, LNG is loaded onto double-hulled ships, which are used for both safety and insulating purposes. Once the ship arrives at the receiving port, LNG is off-loaded into well-insulated storage tanks, and later regasified for entrance into a pipeline distribution network.
Liquefied natural gas can also be shipped in smaller quantities, usually over shorter ocean distances. There is a growing trade in small-scale LNG shipments, which are most commonly made using the same containers used on trucks and in international trade, specially outfitted with cryogenic tanks.
Other small-scale LNG activities include “peak-shaver” liquefaction and storage facilities, which can hold gas compactly for when it is needed in local markets in the U.S. during times of peak demand. LNG is also sometimes imported or exported by truck from this kind of facility.
