Seabed gas extraction first of its kind: METI


Seabed gas extraction first of its kind: METI


Mar 13, 2013

In a reported world first, Japan on Tuesday extracted natural gas from methane hydrate, considered a next-generation energy source, in the Pacific seabed off Aichi Prefecture, the Ministry of Economy, Trade and Industry said.

“We started production of a certain amount of methane gas from around 9:30 a.m.,” a ministry official said, noting that if the gas can be extracted without any problems for about two weeks in the ongoing trial, it will be a “major step” toward future commercial development of the resource.

Large concentrations of methane hydrate are believed to exist under the seabed around Japan. Last October, a research team from Meiji University discovered the substance under the seabed in the Sea of Okhotsk and in the Sea of Japan off Akita, Yamagata and Niigata prefectures. There is also a high possibility that it also exists under the seabed off Shimane Prefecture.

Total deposits of methane hydrate around Japan are estimated to be sufficient to cover domestic consumption of natural gas for about 100 years.

In the trial production conducted about 80 km south of the Atsumi Peninsula, Aichi Prefecture, on Tuesday, methane hydrate located about 1.3 km below the ocean surface was dissolved into gas and water and the gas was collected through a well.

Japan Oil, Gas and Metals National Corp. and the National Institute of Advanced Industrial Science and Technology used a method to decrease pressure of layers bearing methane hydrate to dissociate the solid substance.

The substance consists of a combination of methane and water molecules. The high-pressure, low-temperature environment under the seabed causes water molecules to encase methane, giving it a texture like sherbet.

Chunks of methane hydrate have been likened to burning ice cubes, which easily combust when exposed to flame.

Methane hydrate holds large amounts of combustible methane. When 1 cu. meter of methane hydrate decomposes, it releases about 160 cu. meters of gas that can be burned to generate power.

Methane hydrate can be only generated in a high-pressure, low-temperature environment. Since a temperature of about minus 80 degrees is needed for it to form, it is generally only found in permafrost or deep below the seabed.

Under the fiscal 2013 budget, METI has set aside funds to cover the costs of investigating how much methane hydrate might lie offshore. Regional governments near locations where the material has been discovered are also beginning to coordinate their policies to help promote development of the new energy source.

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