Methane hydrates are deposits of methane that occur in marine sediments under specific conditions of pressure and temperature. Under high pressure and low temperature, the water molecules form ice-like crystals that trap the methane in their latticework. These deposits occur at depths of 300 meters or more wherever there is sufficient methane and water in the sediments.
The map at left [next post] shows those coastal areas where large hydrate deposits are believed to exist. They are illustrated in dark blue. Almost every continent has them offshore. They are especially prevalent in the North Sea and the Arctic, where water temperatures are low, but they are also abundant in the tropics. The only regions where more might be expected are on the northern coast of Europe and in the Mediterranean.
The bar chart at lower left estimates the abundance of methane in hydrate deposits in comparison to other fossil fuels. The disparity is enormous. There is an estimated 3 trillion tons of carbon in hydrate formations, as compared to only 931 billion tons in coal, oil and gas combined.
The diagram at right [next post]shows the zone in which hydrates form. The gas is assumed to bubble up from deep formations and be trapped in the upper sediments. The right conditions generally occur in a zone where water temperatures are between 10 and 20 degreed Centigrade and ocean depth is between 100 and 1500 meters.
Harvesting methyl hydrates will mean drilling into sediments and either reducing pressure or raising the temperature so that the methane molecules can escape their "cage." The Japanese claim to have found a way. They are calling the development a game-changer, as revolutionary as fracking. But others worry that the process may produce huge methane leaks or at the very least become yet a new source for the carbon dioxide burden of the atmosphere. As with all such breakthroughs, there is an upside and a downside to the new technology.
The map at left [next post] shows those coastal areas where large hydrate deposits are believed to exist. They are illustrated in dark blue. Almost every continent has them offshore. They are especially prevalent in the North Sea and the Arctic, where water temperatures are low, but they are also abundant in the tropics. The only regions where more might be expected are on the northern coast of Europe and in the Mediterranean.
The bar chart at lower left estimates the abundance of methane in hydrate deposits in comparison to other fossil fuels. The disparity is enormous. There is an estimated 3 trillion tons of carbon in hydrate formations, as compared to only 931 billion tons in coal, oil and gas combined.
The diagram at right [next post]shows the zone in which hydrates form. The gas is assumed to bubble up from deep formations and be trapped in the upper sediments. The right conditions generally occur in a zone where water temperatures are between 10 and 20 degreed Centigrade and ocean depth is between 100 and 1500 meters.
Harvesting methyl hydrates will mean drilling into sediments and either reducing pressure or raising the temperature so that the methane molecules can escape their "cage." The Japanese claim to have found a way. They are calling the development a game-changer, as revolutionary as fracking. But others worry that the process may produce huge methane leaks or at the very least become yet a new source for the carbon dioxide burden of the atmosphere. As with all such breakthroughs, there is an upside and a downside to the new technology.