Thursday, November 13, 2008

Fire Ice

It looks and feels like a little piece of ice, but when you touch a match to it, it burns with a low, blue flame.

It is methane hydrate, a solid form of water that contains a large amount of methane (natural gas) within its crystal structure. In fact, a single small ice cube can have more than a cubic foot of methane gas locked in it. Moreover, it is stable up to the freezing temperature of water (32 degrees Fahrenheit); under moderate pressure, it can even be stable up to close to room temperature.

Technically methane hydrate represents a physical form of matter called a "clathrate," a lattice-like crystal structure that has holes or windows that can contain other substances.

Methane hydrate occurs naturally under certain ocean and deep-lake conditions. And the world stores are enormous--they may account for as much captive carbon as half the total of all other fossil fuel reserves combined (oil plus coal plus and natural gas in gaseous form).

Over the past ten years, the U.S. and Japanese governments have put millions of dollars into researching the physical chemistry and economic potential of methane hydrate. There are significant problems associated with drilling for it and recovering it for commercial use. But methane hydrate may soon make an important contribution to satisfying humanity's energy-hungry needs.