There’s a large source of carbon-based fuel still largely untapped. Efforts to collect this resource are still in an experimental stage, but the technology has proven to be feasible. Called “flammable ice,” it is methane trapped in ice inside permafrost (frozen rock, soil, or sediment) under the deep ocean.

Estimates show that a cubic meter of frozen methane gas hydrate has 164 cubic meters of methane.

The United States Energy Information Administration (EIA) estimates the frozen mixture of methane and water, called hydrates, at up to 2,800 trillion cubic meters. The estimated total volume is larger than all other carbon-based fuel source combined.

Japan’s Interests

Not blessed with any natural carbon-based energy, Japan imported 90% of its total energy needs in 2014. Globally, it ranks third largest in oil and coal imports. It also ranks first in liquefied natural gas (LNG) imports. The country has more than 50 nuclear reactors, now mostly idle after the disaster at the Fukushima nuclear power plant following the 2011 earthquake and tsunami. The shutdown of the nuclear power plants made the search for new fuel sources an imperative.

Well before the Fukushima disaster, the Japanese Ministry of Energy, Trade and Industry (METI) has spent close to $1 billion from 2002 and 2017 researching methane gas hydrates. The results of the research can unlock methane as an energy source. In addition, natural gas releases only half the carbon dioxide compared to coal. Due to this, Japan wants to replace imported coal with LNG.

The gas hydrates could be found under the oceans surrounding Japan. They have rich reserves within the country’s exclusive economic zone, both along the western Pacific Ocean and the Japan Sea. About 50 kilometers (31 miles) off the coast of Japan is the Nankai Trough, a long narrow trench which has been long studied, including surveying, core sample extraction, and seismic data collection. According to Ryo Matsumoto, a professor of geology at Tokyo’s Meiji University who works at the Gas Hydrate Laboratory, studies show that there are more than 1.1 trillion cubic meters of methane in reserves at the bottom of the Nankai Trough.

Graphic of Methane Hydrate process

Gas Extraction

Methane gas hydrates look like regular ice. However, it holds a large amount of natural methane gas. In its frozen state, the methane does not escape from the ice but it ignites when close to an open flame. Estimates show that a cubic meter of frozen methane gas hydrate has 164 cubic meters of methane.

In 2013, the Japanese government funded the Research Consortium for Methane Hydrate Resources (MH21), a research group composed of experts, scientists, and government policymakers, conducted tests to extract flammable ice. It positioned a drillship over the Daini-Atsumi Knoll, a natural formation under 1,000 meters of water located south of Nagoya. According to Dr. Koju Yamamoto, the MH21 field development technology research group leader, the hydrate melts and separates to gas and water.

The natural environment for hydrates is a combination of low temperatures and high pressure. Hydrates melt by either raising the temperature, or lowering the pressure. However, extraction by heating the water is more expensive than the latter option. In turn, the MH21 project chose depressurization by using a submersible pump to suck water separating it from the sediments, and freeing the gas. The freed gas is pumped to the surface for collection.

The Japanese team were the first to ever extract gas from flammable ice. However, sediments filled the pump after a few days, which halted the on-site research.

There are still other challenges before the bold idea and cutting edge technology becomes mainstream. Shale oil extraction took more than 40 years before the cost and the necessary technology caught up with the need. It may take a while longer before hydrate extraction becomes accepted.

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