"Last February scientists from the National Oceanic and Atmosphere Administration (NOAA) and the University of Colorado, released the findings of a study that claimed that around four percent of methane was escaping into the atmosphere as natural gas was being extracted from a field in Denver.
Now that same group has studied the gas production techniques of a field in Utah and discovered that around nine percent of the methane gas extracted at the gas field was leaking into the air. Methane is one of the most potent greenhouse gases, far more so than CO2, and its escape during the production process of the natural gas now challenges the claims that burning natural gas produces far fewer emissions and is better for the environment than coal.
The shale boom has led to a huge increase in natural gas production and as prices have fallen significantly many utilities have been converting their coal power plants to run on cheap gas. The gas industry has claimed that this transition has helped cut US greenhouse gas emissions across the country because gas releases far fewer carbon emissions than coal.
It turns out that whilst burning the gas is cleaner than coal, the extraction process releases large amounts of dangerous greenhouse gases." ~ Study Finds Shale Gas Not As Clean As Thought