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Number 1 Shimbun

Drilling the Deep: In Search of a New Energy Source

 

MARUM_Methanehydrat_burning_copy.jpg

 Pieces of burning methane hydrate demonstrated on the German research ship, Meteor

 

Sonja Blaschke writes that "burning ice"
could solve the energy
crisis and stop climate change,
but there may be an environmental price

At the end of January 2013, the drill ship Chikyu left Shimizu harbor in Shizuoka prefecture and headed southwest towards Cape Omaezaki. After weeks of preparation, it was on a mission – an experiment that some hoped could be the first step to a solution for Japan’s energy crisis.

In the early morning of March 12, several pumps on the ship went into action, dropping the pressure in a drill hole some 1000 meters under the sea and another 300 meters under the seabed. Hours later, the researchers were rewarded for their efforts when flames shot out of the flare head on the Chikyu: for the first time in history they had successfully extracted gas from a methane hydrate layer, a thick sorbet-like substance in the seabed.

In six days, they retrieved 120,000 cubic meters of gas, far more than expected, before sand eventually choked the machines and the experiment came to a halt. “The next level of methane hydrate research has been reached,” says specialist Professor Gerhard Bohrmann of the Center for Marine Environmental Sciences (Marum) in Bremen, lauding the efforts of his Japanese colleagues.

 

Supporters are enticed by the prospect
that it could possibly satisfy Japan’s energy needs
for the next century.

 

It was a great success for Japan, which has spent far more money than any other country on methane hydrate research. To diversify its energy mix and become more energy independent, Japan has been looking for years to find a home-grown solution. Since the nuclear disaster in Fukushima in 2011, efforts have increased to find alternatives to the costly energy imports that weigh heavily on its trade balance. The supporters of “frozen natural gas,” or “burning ice,” as methane hydrate is sometimes called, brush aside the fact that its exploration is technically challenging, time consuming and prohibitively expensive. They are enticed by the prospect that it could possibly satisfy Japan’s energy needs for the next century.

Marine scientists are fascinated by methane hydrate, too, but as a part of their basic research into the oceans to discover how its exploration would affect the ecosystem of the deep sea. Environmentalists, however, criticize the lack of sustainability and point out possible negative effects on the environment.

It looks like a McShake,” jokes Yuji Morita, Senior Research Fellow at the Institute of Energy Economics (IEE) in Tokyo and member of the government commission for methane hydrate, when he’s asked to explain what Japan’s energy dreams are made of. Methane hydrate only forms at low temperatures of 4 degrees Celsius or less, and between 20 and 40 bar pressure. Under such circumstances the gas is trapped inside a cage of water molecules that surround the gas-filled core and form an ice-like structure.

It’s the reason why 80 to 90 percent of worldwide methane hydrate reservoirs can only be found in the “stability zone” between 500 and 2,000 meters under the mud layer of the seabed, and a little closer to the surface in the polar sea. The rest is thought to be located in the permafrost in polar regions.

To be able to use its energy potential, though, the gas has to be extracted on site from its icy shell. Hot water, gas or even methanol, an antifreeze agent, can be used to melt the crystal cages. However, the most promising method appears to be the one applied in the Japanese trial, lowering the pressure so that it becomes unstable, thereby setting free the natural gas inside.

 

How much of the reserves can be reached
is a different kettle of fish.

 

Methane, a colorless and odorless gas, is created through the degradation process of organic material like plankton that has sunk to the seabed. As the gas is very light, it usually rises up from between the sediments deep beneath the ocean floor until it gets trapped in the stability zone. Fishermen are sometimes surprised to find their nets floating towards the ocean surface after accidentally releasing methane hydrate from its cool grave.

Due to its elusive nature, methane hydrate remained undiscovered for a long time; in fact, research has only intensified since the turn of the millennium. Scientists use data from drillings and numerical models based on decay rates of plankton, but are divided about how much might be hidden under the ocean floor: Professor Klaus Wallmann of the German GEOMAR Helmholtz Centre for Ocean Research Kiel thinks that between 1000 to 5000 gigatons of organic carbon might lie in gas hydrate layers, others estimate 500,000 gigatons. Even conservative estimates are much higher than the reserves of coal, natural gas and oil put together. How much of that can be reached is a different kettle of fish.

chikyu_copy.jpg

The Japanese drill ship Chikyu, which took part in the trial extractions of gas from methane hydrates.

Excitement about the potential new energy source is high in Japan, China, Taiwan, Vietnam, India and South Korea, and all have invested a lot of money in its research. India is thought to possess its biggest reserves though, according to Bohrmann, “the icy mass might not be homogenous and concentrated enough.” After figuratively and literally digging through murky mud for a long time, researchers have found that sandy sediment consisting of sand of a certain pore size is particularly suited for extraction. Luckily for Japan, there are many such reservoirs nearby. The governmental energy organization Japan Oil, Gas and Metals National Corporation (JOGMEC) thinks that about one-tenth of the methane hydrate around Japan is located near Cape Omaezaki alone.

Though European countries are relying on Russian gas fields for the coming decades, they also have intensified their methane hydrate research. Marum researcher Bohrmann explains: “70 percent of the surface of our globe consists of ocean, and there is so much we still need to know about it.” Basic researchers like him are trying to find out how the exploration of methane hydrate, as well as oil, affects the ecosystem of the deep sea. They also want to prove what most scientists believe, but have yet to confirm: that methane hydrate stabilizes the continental slopes that form the border between the shelves and the deep sea.

Research is also being conducted on the effects of global warming on methane hydrate reservoirs and the stability of continental slopes. If too much of the methane hydrate layer dissolves, it could lead to mudslides and even tsunami. And while scientists consider this scenario unlikely, it is not altogether impossible. In the “Storegga Slide” 8000 years ago, underwater landslides near the Norwegian coast triggered megawaves that wreaked havoc across Northern Europe. To reduce such risks, scientists recommend that, prior to any exploration, geotechnical tests be conducted and explorations be done only in marginally inclined areas.

 

Greenpeace Japan's Hisayo Takada argues that it would only prolong the dependence on fossil fuels

 

Another potentially damaging effect of warming ocean temperatures is if the methane gas rises up from the depths and into the atmosphere. Methane is a greenhouse gas 30 times more powerful than carbon dioxide, and would do extensive damage to the ozone layer.

For these and other reasons, environmentalists are skeptical. “Considering our limited carbon dioxide budget – why develop something completely new?” asks Greenpeace Japan energy campaigner Hisayo Takada. She argues that it would only prolong the dependence on fossil fuels, and that resources currently spent on methane hydrate exploration would be better used to further develop already existing technologies and improve energy efficiency.

If such counterarguments are considered at all by the Japanese government, they are shunted aside. Japan wants to finish developing a suitable technology by 2018. Profitability would be reached if they managed to draw out 100,000 cubic meters a day, five times more than in the 2013 test, Wallmann estimates.

The next step would be commercialization, says Morita, with the help of private companies. Mitsui Engineering and Shipbuilding, which was involved in the 2013 production test, has already declared its intentions to participate.

However, Morita believes that another 10 to 15 years will pass until commercial extraction is feasible, as the technology must first be improved and the costs lowered significantly. Just to hire a drill ship for one day sets the government back ¥50 million, he says; others say it costs twice as much.

Greenpeace Japan campaigner Takada says, “We don’t have much time left!” She disagrees with the idea that methane hydrate could be suitable to make the transition from nuclear to renewable energy go more smoothly.

Wallmann, however, supports the continued efforts to try and explore methane hydrate, and predicts a Golden Age of Gas. “In the coming 20 to 30 years, a big part of energy in Asia will be generated from gas hydrates,” he says. The Japanese government seems to agree. In its latest energy plan it reserved generous funds for methane hydrate research – to be used for further data analysis of previous tests and explorations in shallower areas like the Japan Sea.

Many basic research scientists currently pin their hopes on a German project called “Sugar,” which is being held close to the South Korean coast this year. The project aims to discover if carbon dioxide, a side-product of energy generation in thermal power plants, could be liquefied and then injected into the methane hydrate reservoirs deep under the deep seabed. There, carbon dioxide would be converted into the more stable carbon dioxide hydrate, from which methane can be extracted, Bohrmann explains.

If successful, the “burning ice” from the deep sea would not only satisfy energy needs, but also help stop climate change. Bohrmann is excited about the upcoming experiment: “A cycle is created: We get methane and get rid of carbon dioxide.”

Sonja Blaschke is a freelance journalist and producer for German media based in Tokyo since 2005.

 

Published in: April

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