While there have been heated discussions over what to do with Japan’s nuclear power generation, it is important for the government not only to promote development of green energy sources but also to make serious efforts to exploit new fossil fuel resources, especially in the ocean, to operate the thermal power plants substituting for most of Japan’s nuclear power plants now being kept offline.
On Oct. 3, Japan Petroleum Exploration Co. extracted shale oil on a trial basis from 1,800-meter-deep bedrock in the Ayukawa gas field in Akita Prefecture. But the estimated total shale oil deposits in the prefecture is equivalent to slightly less than 10 percent of the oil Japan consumes in one year. The Natural Resources and Energy Agency says that the shale oil in the prefecture will not contribute much to improving Japan’s energy self-sufficiency.
In late November, a panel of the government’s ocean policy headquarters came up with an interim draft report for the nation’s new basic ocean policy. It said that the government should push the development of methane hydrate resources in the seas around Japan by setting numeral targets and timelines so that extracting methane from methane hydrate becomes a viable industry by 2025.
In a low-temperature and pressure environment on the ocean bottom, water molecules exist in a cagelike structure. This structure confining methane molecules is methane hydrate. It is often called “fiery ice” because it looks like ice. If dissociated from water, methane can be collected as natural gas. It is estimated that methane hydrate deposits in the oceans around Japan are equivalent to nearly 100 years of Japan’s natural gas consumption.
It is not easy to extract methane from methane hydrate because the latter exists in the form of solid matter. But Japan has succeeded in getting methane from an underground methane hydrate layer in a test in Canada. In the test, the pressure inside the layer was lowered to let methane vaporize. Around mid-February in 2013, Japan, Oil, Gas and Metals National Corp. plans to start a test to dissolve methane hydrate in a layer some 1,300 meters below the sea surface off Atsumi Peninsula of Aichi Prefecture.
Japan should develop methane hydrate resources in earnest. In doing so, it should work out an efficient method for extracting methane without causing environmental problems. Because Japan’s territorial waters plus its exclusive economic zone are the world’s sixth largest, serious efforts to exploit methane hydrate resources may help to give it an advantageous position in negotiations on imports of crude oil and liquefied natural gas.
At present, Japan’s power companies must import a large amount of LNG as fuel for thermal power plants. The government should accelerate the development of methane hydrate resources by providing sufficient financial support to the entities concerned.