摘要：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.
