Measuring the Climate Impacts of Natural Gas
There are many positive characteristics of natural gas, the main benefit being that natural gas is the lowest-carbon fuel. The numerous advantageous aspects of natural gas have long been recognized. For instance, the Department of Energy’s Alternative Fuels & Advanced Vehicles Data Center says that CNG (compressed natural gas) is 26% less carbon-intensive than gasoline.
Unfortunately, the Environmental Defense Fund (EDF) has recently questioned the facts about natural gas in a paper entitled “Greater focus needed on methane leakage from natural gas infrastructure,” which was published online on April 9, 2012, by the Proceedings of the National Academy of Sciences (PNAS)
However, on the same day the paper was published, the EDF put out a press release noting the preliminary nature of their work: “Thus the paper does not draw hard and fast conclusions about the future implications of any kind of fuel shifting, nor does it answer the question of whether natural gas generation or natural gas-powered vehicles will be better or worse for the climate.”
The EDF paper is based on the Environmental Protection Agency’s (EPA) methane leakage data from natural gas systems, which even the EDF notes is inadequate: “Despite recent changes to EPA’s methodology for estimating CH4[methane] leakage from natural gas systems, the actual magnitude remains uncertain and estimates could change as methods are refined. Ensuring a high degree of confidence in the climate benefits of natural gas fuel-switching pathways will require better data than are available today.” (EDF paper, pg. 4).
Just last December, the Chamber of Commerce of the United States of America challenged the EPA’s methane leakage data, arguing that “EPA’s use of limited and unverified data and reliance on unsupported assumptions do not facially meet the requirements for quality, utility, objectivity and integrity” (p. 4). This was highlighted by a study released by URS which analyzed 1,500 wells from 8 companies across 10 production basins and found that EPA's well completion emissions estimates is 1200% too high.
Immediately following the publishing of EDF’s paper, Energy in Depth released an article entitled “EDF Methane Paper: Constructive, But Premature?” in which they clearly state their disappoint about the premature nature of the paper:
“We were somewhat disappointed to read through EDF’s recent paper…we wish EDF had exercised more caution, shown more patience and waited for a trustworthy set of numbers to be posted by EPA before releasing a report that the organization itself admits is based on skewed data.”
Evidently, the EDF published their paper too quickly, relying on data from the EPA that is argued, by multiple credible sources, to be inaccurate.