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 environmentally friendly fuel across oceans, natural gas must be converted into liquefied natural gas (LNG). LNG is natural gas that has been cooled to –260° F (–162° C), changing it from a gas into a liquid 1/600th 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 and used for more than 50 years and has a strong safety record. LNG vessels have traveled more than 151 million miles during the past 50 years, and more than 119,000 LNG carrier voyages have taken place without major accidents or safety or security problems, either in port or at sea.
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 a flammable liquid, so it will not explode or burn. Like other fuels, when it vaporizes and mixes with oxygen, it is flammable if it is exposed to an ignition source. Even then, there is a limited flammability range: If the concentration of natural gas in the air is below 5 percent or greater than 15 percent, it will not ignite.
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.
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. Safety features include methane detectors, ultraviolet or infrared fire detectors, and regular personnel training.
Worldwide, there are 101 import terminals designed to receive LNG shipments, 24 LNG liquefaction export terminals and more than 200 storage facilities where LNG is kept until needed. Japan, with more than 40 LNG import terminals, has gone without a major safety incident since it began receiving LNG shipments 35 years ago.
Updated: August 2011