An Assessment of Life Cycle Greenhouse Gas Emissions Associated With the Use of Water, Sand, and Chemicals in Shale Gas Production of the Pennsylvania Marcellus Shale

The widespread use of hydraulic fracturing (HF) has enabled a dramatic expansion of unconventional natural gas extraction in the U.S. While life cycle greenhouse gas (LC-GHG) emissions associated with HF have gained attention in recent years, little focus has been devoted to upstream LC-GHG impacts of HF natural gas (Clark, Burnham, Harto, & Horner, 2013; Verrastro, 2012). Focusing on 1,921 wells in Pennsylvania from 2012 to 2013, we used the Economic Input-Output Life Cycle Assessment model to assess LC-GHG emissions associated with production and transportation of chemicals and sand mining. Ton-miles from the transportation of sand and water were assessed with life cycle transportation emissions factors to generate LC-GHG emissions. LC-GHG emissions from upstream inputs assessed in this study equaled 1,374 tons of CO(2)e per well, but account for only 0.63% of the total LC-GHG emissions of HF natural gas. LC-GHG emissions from sand, water, and chemicals are quite small when compared with gas combustion, methane leakage, venting, and flaring from the other phases of the HF process.