WASHINGTON - The United States is facing constraints in its supply of natural gas, and energy projections from the U.S. Department of Energy's (DOE's) Energy Information Administration (EIA) now assume that a natural gas pipeline from Alaska will start production in 2015, while imports of liquefied natural gas (LNG) will increase from 0.6 trillion cubic feet in 2004 to 4.1 trillion cubic feet in 2025. That's because aside from pipelines, the only way to import natural gas is to first liquefy it into LNG for shipping. Until now, that is.

Sea NG Corp., a Canadian company, has announced that the American Bureau of Shipping (ABS) has given design approval to a ship that will carry compressed natural gas (CNG) using a patented system of small diameter high-strength steel pipe coiled into a carousel to store the high-pressure natural gas. The carousel provides support and protection for the pipe and facilitates transport and stacking within the ship. ABS, a nonprofit corporation that sets safety standards for the marine industry, said that Sea NG plans to award contracts later this year for the construction of three CNG ships. Each ship will carry 16 coils of pipe containing a total of 50 million cubic feet of natural gas. These first three CNG ships are intended to service projects in the Caribbean or Mediterranean seas.

Sea NG said the ships are meant to deliver CNG over moderate distances, up to about 1,250 miles, and require minimal on-shore facilities. In contrast, LNG import facilities require significant investments, and some proposed U.S. facilities have faced significant resistance from local residents. Whether CNG shipping can change the outlook for natural gas supplies to the United States remains to be seen, but at least the technology provides another import option.