>>HOWARTH and his colleagues conclude the greenhouse gas footprint of shale gas is likely 20% greater than coal per unit energy, and may be as much as twice as high. <<
Marcellus shale gas emissions only slightly higher
Aug 11, 2011
environmentalresearchweb.org
Overall the researchers estimate that extraction of Marcellus shale gas would produce 3% more greenhouse-gas emissions than extraction of conventional natural gas. When weighed up next to coal, the Marcellus shale is positively glowing, with up to 50% fewer greenhouse-gas emissions, assuming carbon capture and storage is not in place.
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Environmental Research Letters 6 (July-September 2011) 034014
doi:10.1088/1748-9326/6/3/034014
Life cycle greenhouse gas emissions of Marcellus shale gas
Mohan Jiang1, W Michael Griffin2,3, Chris Hendrickson1, Paulina Jaramillo3, Jeanne VanBriesen1 and Aranya Venkatesh1
1 Civil and Environmental Engineering Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
2 Tepper School of Business, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
3 Department of Engineering and Public Policy, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
E-mail: cth@andrew.cmu.edu
Received 13 January 2011
Accepted 14 July 2011
Published 5 August 2011
Abstract. This study estimates the life cycle greenhouse gas (GHG) emissions from the production of Marcellus shale natural gas and compares its emissions with national average US natural gas emissions produced in the year 2008, prior to any significant Marcellus shale development. We estimate that the development and completion of a typical Marcellus shale well results in roughly 5500 t of carbon dioxide equivalent emissions or about 1.8 g CO2e/MJ of gas produced, assuming conservative estimates of the production lifetime of a typical well. This represents an 11% increase in GHG emissions relative to average domestic gas (excluding combustion) and a 3% increase relative to the life cycle emissions when combustion is included. The life cycle GHG emissions of Marcellus shale natural gas are estimated to be 63–75 g CO2e/MJ of gas produced with an average of 68 g CO2e/MJ of gas produced. Marcellus shale natural gas GHG emissions are comparable to those of imported liquefied natural gas. Natural gas from the Marcellus shale has generally lower life cycle GHG emissions than coal for production of electricity in the absence of any effective carbon capture and storage processes, by 20–50% depending upon plant efficiencies and natural gas emissions variability. There is significant uncertainty in our Marcellus shale GHG emission estimates due to eventual production volumes and variability in flaring, construction and transportation.
Full Text: iopscience.iop.org
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The press usually only cites the Howrath study. |
