Friday, May 18, 2007

Methane Hydrate: A Blessing or a Curse

A huge reserve of methane found under the sea could ease our current energy problems, or send our planet into a runaway greenhouse effect.

By: Vanessa Uy

Studies show that the amount of methane hydrate that’s currently found under of all the Earth’s oceans is probably twice as large as our current reserves of other fossil fuels like oil, coal and natural gas combined. Even though all of this methane hydrate has the danger of escaping into the Earth’s atmosphere increasing the effects of global warming, it also has the potential of easing our current energy shortage. Also, methane is the cleanest carbon based fuel in current use.

The mysterious phenomena of deep-sea methane hydrate deposits, is being currently under investigation by marine geologists all over the world. Methane hydrate can also be found in the permafrost layer of the soil in Arctic regions, but deep-sea deposits are more concentrated therefore more economical to mine. Methane hydrate is made up of frozen water or ice that contains large amounts of methane gas trapped in its crystal structure. The chemical process of hydration also contributes to the relative stability of methane hydrate crystals. On extremely rare occasions, methane hydrate fields can suddenly out- gas in huge eruptions. This could explain why some ships mysteriously sank without a trace in the Bermuda Triangle, even on calm weather conditions.

Chemists, geologist and other scientists have now joined forces to study of methane hydrate crystals from its stability aspect to the economics of harvesting it as a source of methane fuel. Certain deep sea beds are now being studied whether the relatively high water pressure of the deep ocean or the relatively low temperature of just a few degrees above freezing are factors that affect the occurrence of methane hydrate crystals.

One of the few research vessels that’s currently studying the phenomena of methane hydrate deposits is the Hamburg-based Meteor. Meteor is a German science vessel that is specially equipped with an autoclave corer that can reach 2000 meters below to extract the methane hydrate seam. This autoclave corer enables her to maintain the ambient water pressure that surrounds the methane hydrate deposits-usually 180 bar- as these samples are brought to the surface to be collected. Then the other samples of methane hydrate are stored in a cryogenic fluid like liquid nitrogen for further analysis in land-based laboratories.

Marine Geologist Gerhard Bormann of Marum Bremen University with a team of chemist and engineers run the research ship Meteor. They are currently involved in the feasibility study of mining methane hydrate from the ocean’s dept without exacerbating the effects of global warming by allowing the methane to leak into the atmosphere. Japanese scientists are also involved in formulating efficient and economical ways of extracting deep-sea methane hydrate deposits.

By melting methane hydrate crystals in the lab, scientists found out that the “frozen” methane expands to 160 times its volume as a gas. Even though by weight, a typical piece of methane hydrate crystal is just made up of 10 to 15 percent methane by weight.

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