The U.S. Environmental Protection Agency (EPA) just released its "Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2009." One of the categories reviewed is "Natural Gas Systems," which includes hundreds of thousands of wells, hundreds of processing facilities, and over a million miles of transmission and distribution pipelines. Among EPA's findings:
- Natural gas systems remained the largest U.S. anthropogenic source category of methane in 2009. Their methane emissions increased 4 percent from 2008 to 2009 due to an increase in production and production wells.
- Emissions from field production accounted for approximately 59 percent of methane emissions and about 34 percent of non-combustion carbon dioxide emissions from the natural gas systems category in 2009.
- Estimates are greater than previously thought for emissions from three sources: gas well cleanups, condensate storage tanks and centrifugal compressors.
- New data allowed EPA to add two sources this year: well completions and re-completions with hydraulic fracturing. According to the EPA: "the high pressure venting of gas in order to expel the large volumes of liquid used to fracture the well formation, results in a large emission of natural gas."
The greenhouse gas emissions associated with natural gas exploration and production is getting a lot of attention recently. NRDC will be reviewing the EPA data more closely, but as EPA discusses and my colleague Dan Lashof notes in his blog, we still need better data to fully understand the extent of these emissions. Even without new data, thanks to EPA's Natural Gas Star program and industry's own reports, we know with certainty that industry can capture these emisions with proven and readily available equipment that will help create more jobs. If companies do not adopt these methods uniformly, we need regulations to require it.