Life cycle greenhouse gas emissions of Marcellus shale gas

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 CO 2 e/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 CO 2 e/MJ of gas produced with an average of 68 g CO 2 e/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.

Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction

“…These concerns include changes in air quality (6), human health effects for workers and people living near well pads (5), induced seismicity (7), and controversy over the greenhouse gas balance (8,9). Perhaps the biggest health concern remains the potential for drinking water contamination from fracturing fluids, natural formation waters, and stray gases (4, 10-12).…”

Implications of the Recent Reductions in Natural Gas Prices for Emissions of CO2from the US Power Sector

“…The advantages of natural gas are even more favorable if the potential climate impact is assessed on time scales much longer than a decade. Jiang et al (26) evaluated the greenhouse gas (GHG) emissions resulting from the use of gas extracted from the Marcellus shale considering the entire life cycle of the gas.…”

“…They argued further, in contrast to Howarth et al (24), that the climate impact of the greenhouse gases emitted in conjunction with exploitation of the Marcellus shale source to produce electricity are significantly lower than those associated with the production of power using coal. They concluded that relatively straightforward measures could be implemented to minimize the potential release of greenhouse gases associated with the extraction of gas from shale (26). A more recent study by Hultman, et al (27) adopting a transparent and consistent approach to comparing the GHG footprints of conventional natural gas, shale gas, and coal, concluded that in terms of electricity generation the GHG impacts of shale gas are 11% higher than those for conventional gas (higher than the value reported by Jiang et al), but only 56% of the impact expected for coal.…”

Economic impact analysis of natural gas development and the policy implications

“…Due to the associated methane emissions from upstream activities, unconventional gas development has shown similar greenhouse footprint as coal. Table 9: Life cycle Greenhouse gas emissions from conventional natural gas (kg CO2-e/kWh) (Agrawal et al, 2014;Burnham et al, 2012;Hardisty et al, 2012;Howarth, 2014;Jiang et al, 2011;PACE, 2009;Stephenson et al, 2011) Reference Region…”

“…Greenhouse Table 10: Life cycle Greenhouse gas emissions from unconventional natural gas (kg CO2-e/kWh) (Burnham et al, 2012;Hardisty et al, 2012;Heath et al, 2014;Howarth, 2014;Jiang et al, 2011;Laurenzi and Jersey, 2013;Stephenson et al, 2011) Reference Type In Australia, the environmental regulations vary from state to state ( Figure 5). In particular, there are moratoria on hydro fracturing in Victoria and New South Wales (The Australian, 2014).…”