The shale gas debate has taken center stage over the past decade in many
European countries due to its purported climate advantages over coal and the
implications for domestic energy security. Nevertheless, shale gas
production generates greenhouse gas and air pollutant emissions including
carbon dioxide, methane, carbon monoxide, nitrogen oxides, particulate
matter and volatile organic compounds. In this study we develop three shale
gas drilling projections in Germany and the United Kingdom based on
estimated reservoir productivities and local capacity.
For each projection, we define a set of emission scenarios in which gas
losses are assigned to each stage of upstream gas production to quantify
total emissions. The “realistic” (REm) and “optimistic” (OEm) scenarios
investigated in this study describe, respectively, the potential emission
range generated by business-as-usual activities, and the lowest
emissions technically possible according to our settings. The latter
scenario is based on the application of specific
technologies and full compliance with a stringent regulatory framework
described herein. Based on the median drilling projection, total annual
methane emissions range between 150–294 Kt in REm and 28–42 Kt in OEm, while
carbon dioxide emissions span from 5.55–7.21 Mt in REm to 3.11–3.96 Mt in
OEm. Taking all drilling projections into consideration, methane leakage
rates in REm range between 0.45 and 1.36% in Germany, and between 0.35 and
0.71% in the United Kingdom. The leakage rates are discussed in both the
European (conventional gas) and international (shale gas) contexts. Further,
the emission intensity of a potential European shale gas industry is
estimated and compared to national inventories. Results from our
science-based prospective scenarios can facilitate an informed discussion
among the public and policy makers on the climate impact of a potential
shale gas development in Europe, and on the appropriate role of natural gas
in the worldwide energy transition.