TOKYO, May 8 (Reuters) - Japan's trade ministry on Monday reported success in producing gas last week by extracting methane gas from methane hydrate deposits offshore Japan's central coast.
The tests being run at two different wells are the first since 2013, when Japan achieved the world's first-ever extraction of gas from offshore deposits of methane hydrate, a frozen gas known as "flammable ice".
Japan's Ministry of Economy, Trade and Industry (METI) said the methane hydrate production tests will continue for a combined four to five weeks. Japan's first methane hydrate tests in 2013 ended abruptly after less than a week due to problems with sand flowing into the well.
Japan, which imports nearly all of its energy sources, has been aiming to launch private sector commercial production of methane hydrates by between 2023 to 2027, but METI officials have said the goal will still be a challenge as many obstacles remain to be solved.
Japan is the world's top importer of liquefied natural gas (LNG), and its need for domestic gas resources has become greater since the Fukushima nuclear crisis in 2011 shut down most of its nuclear power plants and sharply raised fossil fuel imports such as LNG and coal.
Methane hydrate is formed from a mixture of methane and water under certain pressures and conditions. India, Canada, the United States and China are among the countries also looking at exploiting hydrate deposits as an alternative source of energy, the trade ministry said.
A Japanese study has estimated that at least 40 trillion cubic feet (1.1 trillion cubic meters) of methane hydrates lie in the eastern Nankai Trough off the country's Pacific coast, equal to about 11 years of Japanese gas consumption. (Reporting by Osamu Tsukimori; Editing by Tom Hogue)