The greenhouse impact of unconventional gas for electricity generation

Abstract

In our discussion of the use of global warming potential (GWP) values in the Howarth et al (2011) paper, our text implies that the GISS group's 2009 and 2010 papers (Shindell et al 2009 andUnger et al 2010) were contradictory. Such an interpretation does not reflect the conclusions of those papers and was not our intention. First, the 2009 and 2010 papers address GWP and radiative forcing, respectively. Our intentions in that paragraph were (a) to illustrate the possible ways that the GWP and radiative forcing discussions in the scientific community were misapplied to lifecycle analysis of greenhouse gas emissions from unconventional gas extraction, and (b) to underscore that the reasonable questions about GWP raised by Shindell et al (2009) are a justification for retaining a broader, rather than narrower, range of GWP possibilities for this calculation. AbstractNew techniques to extract natural gas from unconventional resources have become economically competitive over the past several years, leading to a rapid and largely unanticipated expansion in natural gas production. The US Energy Information Administration projects that unconventional gas will supply nearly half of US gas production by 2035. In addition, by significantly expanding and diversifying the gas supply internationally, the exploitation of new unconventional gas resources has the potential to reshape energy policy at national and international levels-altering geopolitics and energy security, recasting the economics of energy technology investment decisions, and shifting trends in greenhouse gas (GHG) emissions. In anticipation of this expansion, one of the perceived core advantages of unconventional gas-its relatively moderate GHG impact compared to coal-has recently come under scrutiny. In this paper, we compare the GHG footprints of conventional natural gas, unconventional natural gas (i.e. shale gas that has been produced using the process of hydraulic fracturing, or 'fracking'), and coal in a transparent and consistent way, focusing primarily on the electricity generation sector. We show that for electricity generation the GHG impacts of shale gas are 11% higher than those of conventional gas, and only 56% that of coal for standard assumptions.

Environmental Impacts of Shale Gas in the UK: Current Situation and Future Scenarios

“…per kWh. [23][24][25][26] Human toxicity potential (HTP) At 54 g DCB Eq. per kWh in the central case, shale gas has a 37-43 % higher HTP than electricity from the other two gas options (Figure 3).…”

“…per kWh. [23][24][25][26] Therefore, the impacts of shale gas remain uncertain and, for many impact categories, still unknown. To broaden the understanding of the environmental consequences of shale gas, this paper considers a range of impacts which, in addition to the GWP, include acidification, eutrophication, resource and ozone-layer depletion, photochemical smog and human and eco-toxicity.…”

Toward a better understanding and quantification of methane emissions from shale gas development

“…Advances in drilling and well stimulation techniques have allowed access to previously locked reservoirs of natural gas, such as the Marcellus shale formation in Pennsylvania, which has led to a boom in natural gas production in the last decade (10). This has led to estimations of the carbon footprint of natural gas to examine the impact of increasing our reliance on natural gas for various energy needs (11)(12)(13)(14)(15)(16)). An important unresolved issue is the contribution of well-to-burner tip CH 4 emission to the greenhouse gas footprint of natural gas use.…”

Shale Gas: A Review of the Economic, Environmental, and Social Sustainability

“…Global warming potential (GWP)ofshale gas used for electricity generation. CCGT:combined cycle gas turbine; [9,54,58,[74][75][76][77][78][79][80][81][82][83][84] SCGT:s inglecycle gas turbine. [74][75][76][77][78][79] cles.…”

“…CCGT:combined cycle gas turbine; [9,54,58,[74][75][76][77][78][79][80][81][82][83][84] SCGT:s inglecycle gas turbine. [74][75][76][77][78][79] cles. [85][86][87][88][89][90][91][92] Thee quipment usedo nsite is the main source of these emissions,i np articular, compressors, condensate tanks, and gas pipelines.…”