Posted: November 25, 2012
A source of methane, the primary component of natural gas, can be found in methane hydrate. Methane hydrate is a naturally occurring compound made up of a water/ice cage surrounding a methane molecule. Along with shale development, new natural gas resources such as methane hydrate can play an important role in providing a diversified energy portfolio to meet the growing energy demand, become more self-sufficient in energy supplies, and move toward cleaner energy options.
Methane hydrate requires specific pressure, temperature, water and methane measures to provide solid methane hydrate. Once it is ‘melted’ or exposed to pressure and temperature conditions which make it unstable, the gas molecule is dissociated or released by the water. This is apparent when putting a lit match to methane hydrate and seeing what appears to be burning ice.
Methane hydrate is a good source of natural gas. A cubic foot of solid methane hydrate will release about 164 cubic feet of methane gas. Methane hydrate can be found in both terrestrial and marine environments, such as in sediments beneath the permafrost and in sediments of the earth’s outer continental margins, where suitable conditions for methane hydrates to form can be found. The worldwide volumes of methane found in methane hydrates is considered huge, but poorly known, with estimates ranging from 100,000 to over 1,000,000 trillion cubic feet of natural gas.
Methane is a greenhouse gas that can remain in the atmosphere for about 7 to 10 years before it’s converted to carbon dioxide. With the massive amounts estimated, it can play an important role in the global climate change. The US Department of Energy (DOE) is taking part in national and international programs to evaluate methane hydrate as a potential energy source as well as understand the links between natural methane hydrate systems and the global carbon cycle, to understand the sensitivity of natural hydrate occurrences to likely climate-change scenarios, and to access potential methane release to the atmosphere from possible future development activities. Three major field research projects are under way in the US. There is an offshore project in the Gulf of Mexico studying marine hydrates, and two onshore projects are studying methane hydrate beneath the permafrost in northern Alaska.
More information on methane hydrate research can be found at the US DOE’s National Energy Technology Laboratory (NETL) website at www.netl.doe.gov/methanehydrates