As well as the reserves buried beneath the sea floor, there is another type of methane hydrate deposit that has been gaining attention from Japanese researchers. Efforts to research shallower deposits, very close to the seafloor surface, is also being explored off in the Sea of Japan to the west of the country. Accessing these shallow reserves poses a very different potential risk.
“These are very active biological environments,” says Tim Collett, a senior scientist at the US Geological Survey’s Gas Hydrate Project. “There are whole communities that live off the methane.”
These environments are rich in unique organisms, from bacteria to very large tubeworms and crabs, all specialised to live off the methane as their source of energy. In other parts of the world where these methane-based communities live, they are often protected as rare natural environments.
Beneath the permafrost
Japan’s main efforts in extracting methane hydrate, however are not in the seafloor at all, but in the only other place that flammable ice can found – deep in the permafrost, the permanently-frozen layer of rock or soil that covers the ground at polar regions and high-rise mountains. Researchers from Japan, which doesn’t have its own permafrost, are assisting in the most ambitious on-land production test for methane hydrate so far, in Alaska’s North Slope.
In December, researchers from Japan’s national research programme are set to start work with the US Geological Survey and the US’s Department of Energy, to begin what they hope will be a long-term production test site. While this source of methane hydrate is very different, the methods used to get to it are actually very close.
“The conditions at those reservoirs under the permafrost are pretty similar pressure and temperature conditions as they are in the Nankai Trough,” says Collett. “It turns out, to the best of our knowledge, even though the Arctic and the marine environment are very different, the physical properties of the deposits and how they occur in the sediments appears to be very similar.”
The production techniques used in Alaska could end up being transferrable to the marine environment. But there are still big challenges. A long-term production of methane hydrates hasn’t been carried out anywhere yet, on land or under the sea.
“We’re still very much in research mode,” says Collett.
Given the difficulty of retrieving gas from methane hydrate reserves, and the concerns around extraction, the stakes have to be high for a nation to invest heavily in this technology. Having very few other options in terms of domestic energy makes this hard-to-access source of methane an appealing prospect. Japan is not a country that has other carbon-based sources of energy to fall back on.
“Japan imports a lot of natural gas, but it is very costly. If we have our own domestic resource, [it could] contribute to the energy security of Japan,” says Yamamoto.
As an economic resource, it’s easy to see the appeal of methane hydrate. But, fundamentally, it is just another source of natural gas and burning it would contribute to climate change.
All the social and environmental issues associated with fossil fuels apply to gas hydrates
“The most important thing is the recognition and appreciation that gas hydrates are just another fossil fuel,” says Collett. “All the social and environmental issues associated with fossil fuels apply to gas hydrates.”
In this context, methane hydrates – if they are to play a role in Japan’s energy future – are likely to be used as a bridging fuel, in the transition towards renewables. Natural gas is the least carbon-intensive form of fossil fuel, releasing less carbon dioxide per unit of energy released than coal or oil. But, as a carbon-based fuel, burning it still contributes to climate change.
“We need to shift to renewable energy,” says Koji Yamamoto. “But complete switch to renewable energy [takes] a very long time.”
Even as a transition fuel, gas hydrates could be hugely important, Ruppel says. “Were a country able to efficiently produce methane from these deposits, it could open a new realm in bridge fuels to another energy future,” she says.
How useful a role it can play in the future depends on how quickly methane hydrate can be accessed and produced on a commercial scale. The Japanese government hopes to begin commercial projects exploring methane hydrate between 2023 and 2027, according to its latest Strategic Energy Plan.
This target could be a bit ambitious. Jun Matsushima, a researcher at the Frontier Research Center for Energy and Resources at the University of Tokyo, puts the estimate at around 2030 to 2050. “There is a long way to commercialise methane hydrate,” says Matsushima.
The make-or-break moment will be when a long-term production test can be sustained without technical problems or budget constraints shutting it down, says Ruppel.
“I would guess there will be a long-term production test – from months to more than a year – by 2025. But I don’t have a crystal ball,” Ruppel says.
But at the same time, Japan is committing to moving towards renewable energies and decarbonisation. As technologies for harnessing renewable energy become better and cheaper, the role for fossil fuels – especially experimental and expensive ones like methane hydrate – decreases. The longer it takes to get methane from gas hydrate reserves on a commercial scale, the shorter the useful window for using it may be. The other possibility is that adding in a new accessible source of fossil fuel could delay the transition to renewables, says Collett.
This source of carbon, the most abundant in the world, may be one of the last new forms of fossil fuel to be extracted on a commercial scale. It is also the only one to be developed with the end of fossil fuels in sight. The race for methane hydrates is a unique one, where researchers are working towards a goal that might be made irrelevant by renewables by the time they reach it.
For this reason, methane hydrates may well have a shelf life, but it remains to be seen whether Japan, and other countries pursuing them, will be able to get to them on a sufficiently large scale before they’ve already become expendable.