5 Things You Need to Know About Liquefied Natural Gas (LNG)
By Jennifer Olvera
How LNG is Made and Why It's Appealing
LNG is an odorless, non-corrosive, non-toxic natural gas that's converted into liquid form, generally by cooling the gas to minus 260 degrees Fahrenheit at atmospheric pressure to condense it to a liquid. It can remain in a liquid state to minus 116 degrees Fahrenheit and 673 psig. In this state, LNG is very dense, taking up considerably less volume than vapor (about 1/600). The process of turning natural gas into a liquid removes most of the water vapor, butane, propane, and other gases that are typically found in regular natural gas. The LNG that results is almost entirely methane. Natural gas is one of the cleanest burning fuels.
How LNG is Commonly Used
Most often, LNG is used to power heavy-duty vehicles, such as buses, delivery trucks, and garbage trucks. Currently, most LNG fueling stations are located near major highways.
LNG-Fueled Cars Are Not Mass Produced
There are no light-duty cars available that run on LNG. The Civic GX, a natural gas vehicle (NGV) that's identical to a Civic in appearance and similar in performance, runs on domestic natural gas. However, the natural gas it uses is compressed in a gaseous state and stored in cylinders, rather than in a cryogenic liquid form like LNG. While other compressed natural gas (CNG) light-duty models are available as third-party conversions, the Civic GX is currently the only factory-produced natural gas car in the U.S.
There Are Benefits and Drawbacks
One of the benefits to operating an LNG-powered vehicle is the fact that most of the natural gas available in the United States is produced domestically, thus reducing dependence on foreign companies and creating jobs close to home. LNG is less expensive than gasoline and also outputs significantly fewer greenhouse gas and nitrogen oxide emissions and smog-producing pollutants. Unfortunately, LNG vehicles aren't readily available and can get fewer miles per gallon than gasoline-fueled vehicles.
Storing LNG
Typically, LNG is stored in special tanks below ground to maintain the liquid's low temperature. When cold LNG becomes warmer, a vapor cloud – which can become flammable when the natural gas mixture is between five and 15 percent – rises. In liquid form, LNG isn't explosive. As a vapor, however, it can explode in an enclosed space.
Jennifer Olvera, a graduate of DePaul University in Chicago, has been writing professionally for over a decade. In addition to covering the "green scene" for publications such as Where Magazine and Crain's, she has become one of the preeminent dining, food, and entertainment writers in Chicago. She has regularly been published in Chicago Magazine, Chicago Sun-Times, Chicago Tribune, Zagat, Citysearch.com, and Gayot.com.
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