Michael Richardson, Straits Times 21 Aug 08;
ICE that burns? It sounds like a magician's trick. So do some of the exotic names given to gas hydrate - 'flammable sorbet', 'crystal gas' and 'burning ice'. But recent scientific surveys and test drilling in Asia and elsewhere have proven that this substance exists in massive, potentially recoverable quantities and that it could be an important commercial energy source for the future.
Indeed, some of the world's biggest economies and energy users - including the United States, Japan, China, India, South Korea and Canada - are racing to develop production techniques and equipment to tap gas hydrate and bring it to market within the next decade. For all of them, except energy self-sufficient Canada, the ability to tap new domestic sources of natural gas offers the prospect of substantially reducing dependence on expensive gas imports.
Hydrate deposits up to several hundred metres thick are generally found in two places: on or beneath the deep ocean floor, or underground, close to the Arctic permafrost layer where high pressure and cold temperatures turn natural gas (methane, ethane and propane) into a semi-solid form.
Gas hydrate looks like ordinary ice, although it is sometimes discoloured. But when brought to the surface and allowed to warm, it can be lit with a match. It then burns with a soft orange flame. One cubic metre of gas hydrate releases as much as 164 cubic metres of natural gas, in which methane is usually the chief constituent.
While global estimates vary considerably, the US government's energy department says that the energy content of methane in hydrate form is 'immense, possibly exceeding the combined energy content of all other known fossil fuels', meaning coal, oil and conventional gas.
The presence of hydrates has been inferred from seismic surveys and sub-sea sampling along most of the world's continental shelf margins. Some of the biggest deposits found so far are on the ocean floor off Japan, South Korea, India and China, and on and off US and Canadian Arctic land territory.
The Japanese government announced last year that there were over 1.1 trillion cubic metres of methane hydrates in a Pacific Ocean trench called the Nankai Trough, some 50km from the coast of Honshu, the main Japanese island. This reserve is equivalent to 14 years of Japan's gas use. The country currently imports nearly all the oil, gas and coal needed to run its vast economy, the world's second largest after the US'.
Three years ago, the Japanese government said that the commercial exploitation of methane hydrate was economically viable. Oil was US$54 a barrel then, less than half its present price.
In November last year, the South Korean government said that it had found enough gas hydrate in the sea between South Korea and Japan to meet 30 years of demand. Six months earlier, China announced that it had, for the first time, managed to tap into seabed sediment containing gas hydrate in the northern part of the South China Sea. Initial estimates indicated that the find contained the equivalent of more than 100 million tonnes of oil - about one-third of China's annual oil consumption.
China was the fourth country after the US, Japan and India to achieve this technological breakthrough in the deep-sea search for energy. India announced in 2006 that it had made several huge discoveries of gas hydrate off its east and west coasts.
Since last April, the US has signed separate agreements with India, South Korea and Japan to cooperate in hydrate research, exploration and production. Japan, the US and Canada, working in close collaboration, have achieved several days of continuous extraction of methane from underground hydrate reserves in the Arctic permafrost. Large-scale production tests are planned in the Canadian Arctic this winter and in the US Arctic next year.
Test production from offshore Arctic finds is expected to lag by three to five years, because marine deposits are less well documented than those on land. Sea sampling and drilling are also much more expensive. Japan has said it hopes to start test drilling in the Nankai Trough next year, leading to commercial production by 2016. Korea has a similar production timetable.
However, apart from the high costs and technical challenge, all the hydrate explorers face another possible danger - environmental disaster. While governments are attracted to abundant clean fuel, scientists are concerned about drilling risks that disturb the seabed and trigger an uncontrolled release of methane, a potent greenhouse gas.
The British government's former chief scientific adviser, Sir David King, warned recently that one big unknown about global warming is the stage at which dangerous tipping points may be reached that lead to runaway heating of the planet. He cited as an example the release of methane hydrate deposits in the Arctic.
Some evidence suggests that a catastrophic release of methane from the ocean 55 million years ago, possibly caused by undersea volcanic explosions and landslides, was responsible for making the earth much warmer.
The modern hydrate quest is built on a paradox. When released to the air, methane is a greenhouse gas that traps around 20 times more solar heat in the earth's atmosphere than carbon dioxide, the main global warming gas.
However, when burned, methane releases up to 25 per cent less carbon dioxide than combustion of the same amount of coal. It also emits no nitrogen and sulphur oxides, the gases that harm human health when coal is burned without effective filters.
The world's abundant methane hydrate deposits have been safely stored for thousands of years in the ocean depths and Arctic permafrost. Those who now seek to exploit what is probably the world's greatest reserve of new fossil fuel must therefore be sure that in doing so they improve, not harm, the global environment.
The writer is an energy and security specialist at the Institute of Southeast Asian Studies.
