The world has enormous quantities of natural gas, but much of it is in areas far from where the gas is needed. To move this cleaner-burning fuel across oceans, natural gas must be converted into liquefied natural gas (LNG), a process called liquefaction. LNG is natural gas that has been cooled to –260° F (–162° C), changing it from a gas into a liquid that is 1/600th of its original volume. This dramatic reduction allows it to be shipped safely and efficiently aboard specially designed LNG vessels. After arriving at its destination, LNG is warmed to return it to its gaseous state and delivered to natural gas customers through local pipelines.
LNG is not new. It has been transported for more than 50 years and has a strong safety record. An LNG spill would not damage the ground or leave any residue as it evaporates. In water, LNG is insoluble and would simply evaporate, making water-spill cleanup unnecessary. LNG is not stored under high pressure and is not explosive. Although a large amount of energy is stored in LNG, it cannot be released rapidly enough into the open environment to cause the overpressures associated with an explosion. LNG vapors (methane) mixed with air are not explosive in an unconfined environment.
While converting natural gas to and from LNG, stringent safety and security measures are employed.
The process of cooling natural gas into a liquid is called liquefaction. Like at any industrial facility, security issues for liquefaction facilities are tailored to regional and local concerns. Security can include physical barriers, personnel and equipment access control, site surveillance and intruder alert systems.
Shipping LNG Safely and Securely
LNG ships are equipped with sophisticated leak detection technology, emergency shutdown systems, advanced radar and positioning systems, and numerous other technologies designed to ensure the safe and secure transport of LNG.
LNG ships are double-hulled and heavily insulated, with an extensive cargo safety system. LNG is not stored under pressure. As in all modern oil tankers, sophisticated radar and positioning systems alert the crew to other traffic and hazards around the ship. Distress systems and beacons automatically send out signals if the ship experiences difficulty.
Ships also employ antipiracy and boarding measures and must comply with the requirements of the International Ship and Port Security Code. The cargo control room is manned continuously when cargo is being transferred to and from the ship.
LNG Import and Regasification Terminals
LNG is returned to a gaseous state at LNG import and regasification terminals, which are designed and constructed according to stringent national codes and international standards.
Designs of regasification plants include extensive systems to store and process LNG safely. Safety features include spill containment, methane detectors, fire detection and suppression equipment. Personnel receive regular training in safe practices and fire control. Extensive safety systems monitor equipment and restrict access to terminal property 24 hours a day, 365 days a year. Perimeter fencing, motion detection, closed-circuit TV and lighting are also deployed.
The LNG industry provides appropriate security, planning, prevention and mitigation in close coordination with local, state and federal authorities, including the U.S. Coast Guard. These measures significantly reduce risks.
Worldwide, there are 91 import terminals designed to receive LNG shipments, 28 LNG liquefaction export terminals and more than 200 storage facilities where LNG is kept until needed. Japan, with more than 29 LNG import terminals, has gone without a major safety incident since it began receiving LNG shipments 35 years ago.
Updated: April 2012