It's a gas that wiped out much of life on Earth 275 million years ago, and Japan is now touting it as the world's next unconventional energy supply.

    Known as inflammable ice, or clathrates, the new potential fuel is a sherbet-like substance consisting of methane trapped in water ice. To the eye, it looks remarkably like ice and typically resides just below the seabed off our continental shelves.

    Japanese calculations suggests the resources-poor country has enough supply just off its coasts to meet the economic superpower's energy needs for the next 100 years. The frozen gas is also prevalent in other parts of the globe and can provide more energy than all the world's known gas and oil reserves combined, according to one estimate.

    "The initial area of study in Japan was the coastal region stretching 400 km (from Tokyo to the western tip of Japan's Honshu island). This region alone is thought to hold enough reserves to supply all of Japan with natural gas for nearly 14 years," says the Japanese government, which is leading the trials.

    Japanese researchers working for the government were the first to tap natural gas from seabed methane hydrates this March. Massive technological hurdles stand in the way of extracting the gas, which is difficult to access, as it is often deep below sea level. Some say these resources will never be commercially applicable.

    Tokyo points to the challenges of fracking in the 1990s and says similar technological advances will make energy from methane hydrate a possibility. With few natural resources of its own, a stalled nuclear power program, and little in the way of renewables, Japan is hoping methane clathrate can save it from energy dependency.

    Revised estimates, based on data collected over the last year and released last week, say there are massive deposits of methane hydrate below the Sea of Japan. These will be easier to reach than most gas deposits as they are located close to the seabed surface, officials say. Methane hydrates are believed to collect along geological fault lines, and Japan sits atop a nexus of three of the world's largest deposits.

    "Methane hydrate could become an important energy source for Japan, because a substantial part of the known or proven resources globally are around Japan," says energy technology analyst Gerhard Fasol of Eurotechnology Japan.

    Good news for Japan Inc., which showed boosted figures for manufacturing output recently. With nearly all nuclear power stations offline, Tokyo is fueling its mini boom with imported fossil fuels, particularly propane gas. At $16 per million metric units, compared to around $3.50 in the U.S., this has proven to be very expensive, particularly in light of the recent fall in the yen's purchasing power and a ballooning trade deficit.

    这是一种在2.75亿年前摧毁了地球上大量生命的气体。现在，日本却宣扬它是世界下一个非常规能源供应。

    这种新型潜在燃料俗称可燃冰或笼形化合物，是一种果子露状的物质，由被困在水冰中的甲烷构成。乍看起来，它非常像冰，通常藏匿在略低于大陆架外的海床下面。

    日本的计算显示，作为一个资源贫瘠的国家，日本在其海岸线之外拥有巨额的甲烷水合物储量，足以满足这个经济超级大国在未来100年的能源需求。这种冷冻气体也普遍存在于地球其他地区。一项估计声称，它能够提供的能源比全世界目前已知天然气和石油储量的总和还要多。

    正在引领这项能源开发尝试的日本政府表示：“日本的初始研究区域是绵延400公里（从东京至日本本州岛西端）的沿海区域。我们认为，仅这个地区的储量就足以为日本全国供应近14年的天然气。”

    今年三月份，为日本政府工作的研究人选率先从海底的甲烷水合物中提取天然气。提取这种气体面临巨大的技术障碍——因为它常常深藏于海平面之下，难以获取。一些人认为，这些资源永远也无法实现商业应用。

    东京方面开始瞄准水力压裂法在20世纪90年代所面临的挑战，并随即声称，类似的技术进步将使得从甲烷水合物中获取能源成为可能。鉴于日本自身的自然资源贫瘠，核电计划受阻，再加上可再生能源寥寥无几，日本希望甲烷水合物能够使该国摆脱能源依赖症。

    根据过去一年收集的数据，并于上周发布的经修订估算显示，日本海(Sea of Japan)海底储藏有大量甲烷水合物。日本官员表示，由于这些水合物靠近海床表面，它们比大多数天然气资源更容易获取。据说，沿着地质断层线可收集甲烷水合物，而日本则坐落于世界三大甲烷水合物储藏的汇聚之处。

    “对于日本来说，甲烷水合物可能会成为一项重要的能源来源，因为在全球已知或探明的资源中，有相当大一部分位于日本周围，”日本欧洲技术公司(Eurotechnology Japan)的能源技术分析师格哈德•法索尔说。

    对于制造业产出数据近期获得提振的日本公司来说，这是一个好消息。由于几乎所有的核电站都停止运营，东京正在用进口的化石燃料，尤其是丙烷气，支撑日本经济最近一波迷你繁荣。每百万英热单位16美元的价格（美国的价格大约为3.50美元），已被证明是非常昂贵的，特别是在日元购买力近期下降，贸易赤字不断膨胀的大背景下。

    The state-owned Japan Oil, Gas and Metals National Corporation (JOGMEC) is behind the successful methane hydrate drillings so far, but it says private companies will take over once test drilling finishes sometime between 2016 and 2018.

    The Japanese team say they have cracked technical difficulties by sending down what officials describe as "an excavator" one kilometer below the waves. There the machine separates solidified methane hydrate into water and natural gas, and funnels the gas up to the surface.

    "Holes are drilled into the methane deposits to produce water to decrease the pressure, allowing the methane to separate out from the ice-like material and flow up the wellhead," explains Koji Yamamoto, project director of JOGMEC's Methane Hydrate Research Team.

    While some welcome the potential benefits a new supply of energy, others point to the dangers of tampering with unstable beds of frozen gas and adding more CO2 to the atmosphere.

    "Environmentalists are horrified by the idea of releasing huge quantities of methane from under the seabeds," says Leo Roodhart, director of the Roodhart Energy Consultancy. (Methane gas is a greenhouse gas that's 20 times more potent than carbon dioxide.)

    "Although methane is a cleaner-burning fossil fuel than coal or oil, the as-yet untapped methane hydrates represent 'captured' greenhouse gasses that some believe should remain locked under the sea. The mining of methane ice could also wreak havoc on marine ecosystems."

    Yamamoto disagrees that there is any danger of such blowouts or major environmental damage -- although a small methane hydrate blowout was linked to the BP (BP) spill in the Gulf. Larger releases of methane from clathrate beds throughout history, known as the actions of a "Clathrate gun," have been responsible for mass extinction events.

    Researchers do not agree on the risks associated with methane hydrate exploration for commercial energy use. Oceanographer and Rice University professor Gerald Dickens agrees with the Japanese research team, arguing that there is little danger of such catastrophes coming from human action.

    "The only potential issue in regards to drilling would be if there is greatly over-pressured gas immediately beneath the gas hydrate," Dickens says. "However, there is growing belief and rationale to suggest that this cannot occur in nature. So, as far as drilling is concerned, there should be no issue."

    Tim Collett of the United States Geological Survey, a leading expert on methane hydrate, believes it is possible that both natural and human induced changes can lead to hydrate destabilization, triggering catastrophic landslides.

    "Evidence implicating gas hydrates in triggering seafloor landslides has been found along the Atlantic Ocean margin of the United States and off northern Europe," he told the U.S. Congress in 2004. "These processes may release large volumes of methane to the Earth's oceans and atmosphere."  

    到目前为止，日本国家石油天然气和金属公司( Japan Oil, Gas and Metals National Corporation )一直肩负钻探甲烷水合物之责，但这家公司表示，一旦试钻于2016年至2018年之间某个时候完成，私人公司将接管钻探业务。

    日本钻探队表示，他们向海浪下1公里处发送了一台被官员称为“挖掘机”的机器，从而破解了技术难关。在海下，这台机器把固化的甲烷水合物分解为水和天然气，然后将天然气传送至海平面。

    日本国家石油天然气和金属公司甲烷水合物研究团队的项目总监山本浩二解释：“我们给甲烷水合物钻了一些孔，生成水，以减少压力，从而使甲烷从冰状物质中分离，向上流动至井口。”

    虽然一些人欢迎一种全新能源供应的潜在好处，但其他人指出，钻探冷冻气体构成的不稳定床体有一定的危险性，会给大气增添更多的二氧化碳。

    “从海床下释放大量甲烷的想法吓坏了许多环保人士，”鲁德哈特能源咨询公司(Roodhart Energy Consultancy)主管利奥•鲁德哈特表示（甲烷是一种温室气体，其强度比二氧化碳大20倍）。

    “虽然相比于煤或石油，甲烷是一种更加清洁的化石燃料，但尚未利用的甲烷水合物其实是‘被捕获的’温室气体，一些人认为它们应该继续被锁定在海下。开采甲烷冰也可能对海洋生态系统造成严重破坏。”

    山本浩二并不认为存在这种井喷或重大环境破坏的危险，尽管一个小规模的甲烷水合物井喷与此前英国石油公司(BP)的墨西哥湾漏油事件有关。纵观历史，从包合物床体大规模释放甲烷——这种活动被称为“包合物枪”——一直是造成大规模灭绝事件的原因之一。

    研究人员并不认同与出于商业能源使用的甲烷水合物勘探相关的风险。海洋学家，莱斯大学(Rice University )教授杰拉尔德•狄更斯同意日本研究团队的观点。他认为，人类活动几乎不可能造成如此大的灾难。

    “与钻探有关的唯一一个潜在问题是，在天然气水合物的正下方是否存在承受过大压力的气体，”狄更斯说。“然而，越来越多的理由促使我们相信，这种事情其实不可能发生。所以，就钻探而言，应该是没有问题的。”

    甲烷水合物领域的顶级专家、美国地质调查局(United States Geological Survey)的蒂姆•科利特认为，自然和人类引发的改变有可能导致水合物失去稳定性，造成灾难性滑坡。

    2004年，他在出席美国国会听证会时声称：“在美国大西洋沿岸和北欧沿岸已经发现了一些涉及天然气水合物引发海底滑坡的证据。这些活动可能给地球的海洋和大气释放出大量甲烷。”（财富中文网）

    译者：任文科