Initial findings from a new comprehensive study undertaken by the Environmental Defense Fund and the University of Texas found that methane leakage rates from natural gas systems were far below estimates of previous studies.
In 2011, a study released from Cornell University led by ecologist Robert Howarth purported to show high levels of methane “leakage” from natural gas systems, including wells that had been hydraulically fractured. The Howarth study indicated that as much as 7.9 percent of natural gas developed from shale was leaking into the atmosphere thus negating its carbon-friendly advantages.
Studies since the release of the Howarth report have all tended to dispute or outwardly challenge the findings contained in the report. However, initial findings from the new study should leave little doubt.
The first part of the EDF study confirms the consensus reached by most scientists that methane leakage rates from natural gas systems were far below the estimates provided in the Howarth report. The study reviewed emissions associated with well development, production, and completions and found leakage of methane fell below estimates made by the United States Environmental Protection Agency (USEPA). The agency's most recent data found that overall leakage from the natural gas production process was actually below 1.5 percent.
Using their own writings, critics of the use of natural gas have claimed that leakage rates must fall below 2 to 3 percent in order to obtain any benefit from the use of natural gas. This report simply confirms USEPA's findings of leakage rates well below those found in the Howarth study and even below the thresholds set forth by critics of the natural gas industry.