Citizen's Guide – 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
Photo Courtesy of www.lngoneworld.com
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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
Photo Courtesy of www.lngoneworld.com
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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
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.
Photo Courtesy of USCG PA3 Donnie Brzuska
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USCG officers inspect vessel
Photo courtesy of US Coast Guard |
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