China and India Exploit Icy Energy Reserves

I wrote about methane hydrates a long time ago. As the graph shows, there is a ton (make that billions of tons) of energy stored in them. And now it looks like they might start to be exploited.

China and India have reported massive finds of frozen methane gas off their coasts, which they hope will satisfy their energy needs.

World reserves of the frozen gas are enormous. Geologists estimate that significantly more hydrocarbons are bound in the form of methane hydrate than in all known reserves of coal, natural gas and oil combined. "There is simply so much of it that it cannot be ignored," says leading expert Gerhard Bohrman of the Research Center for Ocean Margins (RCOM) in the northern German city of Bremen.

Methane, trapped in an icy cage of water molecules, occurs in permafrost and, in even greater quantities, beneath the ocean floor. It forms only under specific pressure and temperature conditions. These conditions are especially prevalent in the ocean along the continental shelves, as well as in the deeper waters of semi-enclosed seas (see graphic).

From this map it appears that methane hydrates are pretty evenly split around the globe, with the exception that there aren't many around Europe.

The People's Republic of China is investing millions to study this massive source of energy. The same holds true for India, South Korea and Taiwan, all nations that are on a fast track to surpassing the West as economic powers.

The Chinese researchers found the methane hydrate, also known as crystal gas, because of its molecular structure, in a layer of sediment 15 to 20 meters (50 to 65 feet) thick off the Chinese coast. "It was embedded in clay and silt ," says John Roberts, whose firm Geotek provided the technical equipment for the drilling expedition.

This is the sort of information natural gas companies like to hear. The porosity of this sediment mix is well suited to drilling for the gas. "The gas hydrate has never found in this form before," Roberts explains. One possible method would involve the use of drilling tubes that would conduct heated fluid into the cold reservoirs. This would dissolve the icy cage encasing the methane. The next step would be to capture the gas through a second opening.

If China were to switch from coal to methane, that is good news from a pollution and global warming standpoint.

On the other hand, if methane hydrates are used along with the current fossil fuels, there would be serious additional carbon dioxide emissions. But there appears to be a silver lining regarding this.

When a certain amount of pressure is applied to the cage-like crystal structure, carbon dioxide can penetrate the layer of ice, at which point it displaces the methane. Then a new cage of frozen water molecules forms around the carbon dioxide. "This behavior has already been demonstrated in laboratory experiments," says Wallmann.

He is also impressed by the ratio at which the gases are exchanged. For each dissolved molecule of methane, up to five molecules of carbon dioxide disappear into the ice cage.

In addition, says Wallmann, the ice encases the CO2 in a more stable manner than it does the methane. "I cannot imagine a better way to sequester carbon dioxide," Wallmann explains, adding: "We are pursuing this approach with great interest."

Interesting. Replace fire ice with dry ice.

via Spiegel