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LNG Overview


What is LNG?
LNG is liquefied natural gas (methane) that has been cooled to an extremely cold temperature (-260° F/ -162.2° C). At standard atmospheric conditions, methane is a vapor, not to be confused with gasoline, which is a liquid.

Where does it come from?
Indonesia, Algeria, Malaysia, Qatar and Trinidad are currently the leading exporters of LNG. Russia and Iran also have the greatest potential.

How is LNG shipped?
Specially designed ships are used to transport LNG to U.S. terminals. They have double hulls and are constructed of specialized materials that are capable of safely storing LNG at temperatures of -260° F/ -162.2° C.

LNG Tanker with Membrane GT containment systems
LNG Tanker with Membrane GT containment systems
Photo Courtesy of www.lngoneworld.com

Security escort for LNG tanker
Security escort for LNG tanker
Photo courtesy of US Coast Guard

Where do ships unload LNG?
Ships unload LNG at specially designed terminals where the LNG is pumped from the ship to insulated storage tanks at the terminal. LNG is also converted back to gas at the terminal, which is connected to natural gas pipelines that transport the gas to where it is needed. Specially designed trucks may also be used to deliver LNG to other storage facilities in different locations.

LNG Ship Unloading at Terminal
LNG Ship Unloading at Terminal
Photo Courtesy of www.lngoneworld.com

USCG boat provides security for LNG tanker in harbor
USCG boat provides security for LNG tanker in harbor
Photo courtesy of US Coast Guard

How is LNG stored?
LNG is stored in double-walled, insulated tanks that are designed to prevent any gas from escaping. There is also a dike or impounding wall around the tank that is capable of containing the entire volume of the tank, in the unlikely event of a spill. This would prevent any LNG from flowing off the site.

LNG Storage Tank
LNG Storage Tank
Photo Courtesy of FERC


Why make LNG?
Cooling natural gas to -260° F/ -162.2° C changes it from a vapor into a liquid. This reduces the space natural gas occupies by more than 600 times, making it a practical size for storage and transportation.

Is LNG explosive?
In its liquid state, LNG is not explosive. When LNG is heated and becomes a gas, the gas is not explosive if it is unconfined. Natural gas is only flammable within a narrow range of concentrations in the air (5% to 15%). Less air does not contain enough oxygen to sustain a flame, while more air dilutes the gas too much for it to ignite.

How is public safety addressed?
In the event of a spill, LNG vapors will disperse with the prevailing wind. Cold LNG vapor will appear as a white cloud. To keep the public safe, flammable vapor (gas) dispersion exclusion zones are established for LNG facilities.

If LNG is spilled in the presence of a flame, a very localized fire will result. Since this fire would burn with intense heat, thermal exclusion zones are also established.

Flammable vapor and thermal exclusion zones are determined to keep the public at a safe distance from LNG facilities.

How are LNG tankers and facilities being kept secure?
Security measures for land-based LNG facilities and onshore portions of marine terminals, are required by U.S. Department of Transportation regulations. Examples of these requirements include security patrols, protective enclosures, lighting, monitoring equipment, and alternative power sources.

Security measures for the offshore portions of marine terminals are required by U.S. Coast Guard regulations. The Coast Guard prevents other ships from getting near LNG tankers, while in transit or docked at a terminal.

Interstate natural gas companies receive security updates and alerts on a regular basis from federal agencies, including the FBI. A Security Task Force has also been formed. FERC has also removed Critical Energy Infrastructure Information pertaining to LNG storage facilities from its website.

The Coast Guard provides a security zone for a LNG shipment
The Coast Guard provides a security zone for a LNG shipment.
Photo Courtesy of USCG PA3 Donnie Brzuska

USCG officers inspect vessel
USCG officers inspect vessel
Photo courtesy of US Coast Guard


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Updated: June 28, 2010