Japan examines ways to harvest frozen fuel

TOKYO — Like an ice that burns, methane hydrate is cold, white and would light up like a gas stove if held to a flame. So much of the frozen fuel naturally blankets the seabeds off Japan and elsewhere that scientists say it could power the world for centuries.

Yet as soon as researchers plumb the depths and pull the potentially revolutionary energy source to the surface, the frosty crystallized methane starts to fizz and bubble to oblivion as it warms up, gasifies and dissolves into the ocean.

Most countries don’t even bother exploring offshore reserves for lack of harvesting technology. But in resource-poor Japan, plucking the deep-sea bounty off its shores is more than science fiction; it is a national initiative Tokyo hopes will become reality by 2015.

“Japan’s domestic resources are almost zero, so nonconventional sources are a top priority,” said Tetsuo Yonezawa of the methane hydrate research team at the government-backed Japan National Oil Corp. “There is more than 100 years worth of Japanese natural-gas consumption there.”

Japan’s push heats up in January, when a drilling ship sets sail for the choppy Pacific Ocean off south-central Japan to dig 10 to 20 wells in methane hydrate beds along the Nankai Trough, more than 3,630 feet under water.

Japan hopes to determine by 2011 whether commercial methane hydrate mining is economically feasible and, if so, begin doing it four years later.

Methane hydrate is a crystal structure of methane gas surrounded by water molecules, held together by freezing temperature and crushing pressure. Separating the two yields the methane, or common natural gas, and water.

Knowledge of the substance dates to the 1890s, but it has not caught on as an energy source because it is found in Arctic permafrost and deep-ocean sediments.

Worldwide resources, however, are huge — 875,000 trillion cubic feet, or about twice as much carbonized energy as worldwide coal, oil and ordinary gas resources combined, estimates show.

Deposits around Japan are just a fraction of that, but Japan believes it is worth shelling out $120 million next year alone on methane hydrate research to boost its energy self-sufficiency. The island nation imports about 97 percent of its natural gas and virtually all of its crude oil.

Japan is not alone in pursuing methane hydrate, but is perhaps the most desperate.

The U.S. Geological Survey has estimated the quantity of gas hydrates in the United States at 336,000 trillion cubic feet, 200 times its conventional natural gas resources and reserves.

The U.S. Congress also has appropriated millions of dollars for research, but projects are focused as much on academic as commercial applications — in part because methane hydrate on other planets is envisioned as a fuel source for space travel.

The entire Siberian tundra is laced with the frozen fuel, but Russia is so rich in crude oil and natural gas that it spends little time or money trying to perfect complex methane-hydrate mining techniques.

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