IEA的说法只怕是从EIA那里来的，但可能已经price in. 美国是有很多页岩天然气，但其生产成本相当高，因为需要大量钻井，CHK等因钻井负了大量的债务，如果天然气维持现在低价，这些公司将还不了债，所以它们就不钻井了。所以有大量页岩天然气资源，不意味着价格就要低到现在这种价位。

http://www.eia.doe.gov/oiaf/aeo/overview.html

The price of natural gas at the wellhead is lower in the AEO2010 reference case than in the rapid ramping up of shale gas production, particularly after 2015. AEO2010 assumes a larger resource base for natural gas, based on a reevaluation of shale gas and other resources, and a more rapid rate for bringing new resources into production, based on observations of the industry’s current capability.

In the AEO2010 reference case (as in the updated AEO2009 reference case), natural gas prices increase in the short term from the low prices observed in 2009 that resulted from the sharp economic downturn. After 2012, prices continue to rise in the AEO2010 reference case, but more slowly, as additional resources are brought into production to meet demand growth. Natural gas wellhead prices reach $8.06 per thousand cubic feet (2008 dollars) in 2035.