Oct 2012 Has US shale gas reduced CO2 emissions? - A Tyndall Centre report
Since 2007, the production of shale gas in large volumes has substantially reduced the wholesale price of natural gas in the US. This report examines the emissions savings in the US power sector, influenced by shale gas, and the concurrent trends in coal exports that may increase emissions in Europe and Asia.
Electricity generated by the combustion of natural gas is generally considered to have a lower emissions intensity per unit electricity than that generated by burning coal. The relative lifecycle carbon footprint of gas produced by hydraulic fracturing is contested and at present there is a shortage of independent primary data. However, trends in the absolute quantities of CO2 emissions from combustion are less problematic and no less important when considering the implications of the US shale gas boom.
The calculations presented in this report suggest that more than half of the emissions avoided in the US power sector may have been exported as coal. In total, this export is equivalent to 340 MtCO2 emissions elsewhere in the world, i.e. 52% of the claimed 650 MtCO2 of potential emissions avoided within the US.