What Matters: October 2005
Is LNG Safe?
By James A. Fay SM '47
Photo: ©istockphoto.com.
Natural gas is becoming a global commodity. Unlike oil or coal, which can be shipped in transoceanic bulk cargo ships from remote producer to consumer markets worldwide, natural gas has to be pipelined from well to home or factory. But wells close to consumers are being depleted, and new, easily recovered gas lies in remote locations oceans away. New technology makes it both economical and efficient to convert the gas to a very cold liquid (called liquefied natural gas, or LNG) and transport it in insulated supertankers to special LNG terminals in market countries, where it is gasified and pumped into existing gas pipelines for sale to consumers.
While American consumers and government officials decry our dependence on unreliable overseas suppliers of crude oil, the natural gas industry is girding for a vast expansion in U.S. imports of natural gas in the form of LNG from the same overseas sources. To land this flood of LNG, new import terminals must be constructed, at least six or eight by 2010 in the view of U.S. officials, and even more by 2020. This prospect has attracted proposals for more than 60 new terminals to be located on the U.S. Gulf, Atlantic, and Pacific coasts, as well as nearby Canadian, Mexican, and Bahamian shores. Only a fraction of these are needed, or will be built.
The special technology of LNG marine tankers and their accompanying import terminals has raised questions of the safety of transporting and storing this liquid fuel in large bulk quantities. As a liquid, natural gas is extremely cold and boils furiously when accidentally spilled on land or water. If ignited, it will burn quickly—10,000 tons spilled on water would be consumed in only a few minutes. Gigantic fires would spread harmful thermal radiation out to distances of a mile, causing burns and possibly death to unprotected bystanders.
There have been no such major spills on water and none on land since the 1940s in the U.S. But recent boat bomb attacks on a U.S. destroyer and French crude oil tanker in the Persian Gulf have alerted the U.S. Coast Guard to the potential for a terrorist attack on LNG tankers entering U.S. harbors, such as Boston, where they pass close to densely populated downtown areas. The heavily armed patrol boats surrounding current LNG tanker landings, instituted since 9/11, have attracted public attention and anxiety, especially in communities where new terminals have been proposed.
Proposals for terminals in or near densely populated urban areas have uniformly met with the spirited resistance of nearby residents and some public officials. While the safety issue is paramount initially, ultimately it is the incompatibility of the hard-core industrial nature of the facility with longer-term goals of community development that defines the issue. This appears to be true even in towns of low population density—such as Harpswell, Maine—where broadly shared community values of quality of life can overcome the commercial attractiveness of industrial development to hard-pressed taxpayers and job seekers.
There is a technological alternative to siting LNG import terminals at waterfront locations for which higher-valued uses are desired or planned. LNG tankers can be equipped to transform their liquid cargo into high pressure gas as it is discharged into an undersea gas transmission pipeline miles from shorelines, whether urban or rural, thereby mooting the safety issue for the onshore public. A current offshore LNG terminal in the Gulf of Mexico uses an existing pipeline from an offshore gas well to do just this.
The residual environmental effects are much less than those for in-harbor sites where channel dredging, land and harbor traffic management, military style security procedures, and other disruptive measures have to be instituted. The proponents of offshore terminal systems claim that the cost of the system is only 10 percent greater than that of onshore terminals, and offshore terminals can be constructed much more quickly.
Few of the proposed U.S. terminals are of this type, however. There are more than 45 proposals for LNG terminals in the U.S. now in various stages of consideration. Of these, less than a dozen are offshore terminals. In New England and eastern Canada, there are 15 active proposals, of which three are offshore. Although the opposition to offshore terminals is much less intense than for the onshore sites, the LNG industry prefers the traditional tank-on-harbor-front-shore, which is the historic model of the oil industry, mostly because of decades of experience in importing crude oil by marine supertankers.
Is LNG safe? It can be, but not when the industry practice is business as usual.
About the Author
James A. Fay SM '47 is professor emeritus of mechanical engineering at MIT. His current field of interest is environmental engineering, and his recent research activities have concentrated on air and water pollution problems including the dispersion of air pollutants in the atmosphere, acid rain, the safety hazards of liquefied gases, renewable energy (including small-scale tidal power), and the spread of oil and other hazardous liquids on the ocean. He was chairman of both the Massachusetts Port Authority (1972-1977) and the Air Pollution Control Commission of the City of Boston (1969-1972) and has served on 12 boards, committees, and panels of the National Research Council, including two terms on the Environmental Studies Board. He is currently a director emeritus of the Union of Concerned Scientists and was formerly a director of the Conservation Law Foundation. Professor Fay received his BS from the Webb Institute of Naval Architecture in 1944, an SM in Ocean Engineering from MIT in 1947, and a PhD from Cornell University in 1951.
What Matters is a guest opinion column written by a different MIT alumnus or alumna. The views expressed are entirely those of the author and do not necessarily represent the views of the Alumni Association or MIT. Interested in writing a column? Email whatmatters@mit.edu.
