Production of shale gas

Discussion on the carbon footprint of shale gas production is ongoing, with another study (Shale gas production: potential versus actual greenhouse gas emissions) published by MIT - Massachusetts Institute of Technology authors in November, 2012. Their findings reiterate what many recent studies have suggested; greenhouse gas (GHG) emissions of shale gas wells are slightly, and not extensively, higher than the emissions of conventional natural gas wells (e.g.,  see Weber and Clavin, 2012 and Forster and Perks, 2012).

The MIT authors calculate that the total fugitive GHG emissions from U.S. shale gas related hydraulic fracturing in 2010 represent 3.6% of the estimated fugitive emissions from all natural gas production-related sources in that year. They state that, “… the production of shale gas and specifically, the associated hydraulic fracturing operations, have not materially altered the total GHG emissions from the natural gas sector. At the same time the authors state that, “… fugitive emissions from the overall natural gas sector are a proper concern”.

Fugitive emissions of the natural gas sector

Life-cycle GHG emissions within the whole (conventional and unconventional) natural gas system have recently received much attention in the scientific community. An editorial in Nature magazine (Methane leaks erode green credentials of natural gas) summarizes the current scientific debate on fugitive emissions. It includes reports on high methane leakage rates, measured at natural gas fields in the US, which were presented at an American Geophysical Union (AGU) meeting in December, 2012.

“Whether the high leakage rates claimed in Colorado and Utah are typical across the US natural-gas industry remains unclear. The NOAA [National Oceanic and Atmospheric Administration] data represent a “small snapshot” of a much larger picture that the broader scientific community is now assembling”, says Steven Hamburg, chief scientist at the Environmental Defense Fund (EDF) in Boston, Massachusetts.

Natural gas and emission targets

Not only leakage rates from production and distribution have been in focus recently, but also greenhouse gas emissions from the increased burning of natural gas for energy production. The burning of potentially very large worldwide resources of shale gas may be counterproductive to the goal of reducing emissons, when GHG emissions are not captured at power plants and when natural gas does not replace, but instead adds to the burning of coal. This issue has been addressed by two new studies (see below) and also by the International Energy Agency IEA.

The IEA states in its 2012 report, “Golden rules for a golden age of gas”: “… greater reliance on natural gas alone cannot realize the international goal of limiting the long-term increase in the global mean temperature to two degrees Celsius above pre-industrial levels. Achieving this climate target will require a much more substantial shift in global energy use. Anchoring unconventional gas development in a broader energy policy framework that embraces greater improvements in energy efficiency, more concerted efforts to deploy low-carbon energy sources and broad application of new low-carbon technologies, including carbon capture and storage, would help to allay the fear that investment in unconventional gas comes at their expense.”

Broderick and Anderson, 2012: Has US Shale Gas Reduced CO₂ Emissions? (Link to study)

Meindertsma and Block, 2012: Effects of New Fossil Fuel Developments on the Possibilities of Meeting 2°C Scenarios. (Link to study)