I read this in the new york times:

The report by the Potential Gas Committee, the authority on gas supplies, shows the United States holds far larger reserves than previously thought. The jump is the largest increase in the 44-year history of reports from the committee.

The finding raises the possibility that natural gas could emerge as a critical transition fuel that could help to battle global warming. For a given amount of heat energy, burning gas produces about half as much carbon dioxide, the main cause of global warming, as burning coal.

Estimated natural gas reserves rose to 2,074 trillion cubic feet in 2008, from 1,532 trillion cubic feet in 2006, when the last report was issued. This includes the proven reserves compiled by the Energy Department of 237 trillion cubic feet, as well as the sum of the nation’s probable, possible and speculative reserves.

The new estimates show “an exceptionally strong and optimistic gas supply picture for the nation,” according to a summary of the report, which is issued every two years by a group of academics and industry experts that is supported by the Colorado School of Mines.

Much of that jump comes from estimated gas in shale rocks, which drilling companies have only recently learned how to tap. They have developed a technique called hydraulic fracturing, in which water is injected at high pressure into wells to shatter rocks deep underground, helping to release trapped gas.

The method, perfected in recent years in places like Texas and Pennsylvania, has set off a boom in new drilling, but is coming under increasing regulatory and environmental scrutiny. Shale gas accounts for 616 trillion cubic feet of reserves, or a third of the total, according to the report.

“New and advanced exploration, well drilling and completion technologies are allowing us increasingly better access to domestic gas resources — especially ‘unconventional’ gas — which, not that long ago, were considered impractical or uneconomical to pursue,” said John B. Curtis, a geology professor at the Colorado School of Mines and the report’s principal author.

The huge increase in estimated gas supplies comes just as concerns about energy security and climate change are prompting the most profound shift in energy policy since the oil shocks of the 1970s.

http://www.nytimes.com/2009/06/18/bu...