Life cycle greenhouse gas emissions from shale gas compared to coal: An analysis of two conflicting studies

July 1, 2011

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A recent series of studies and rebuttals have debated the greenhouse gas impacts of shale gas production as compared to coal. Post Carbon Institute Fellow David Hughes, author of the groundbreaking report, "Will Natural Gas Fuel America in the 21st Century?", provides an analysis of two conflicting studies. His conclusion: Shale gas is worse than coal for the climate over a 30-50 year timeframe, depending upon the technology used.

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Abstract

Two studies with conflicting conclusions have recently been produced on full cycle greenhouse gas emissions from shale gas production, one from scientists at Cornell University and another from a scientist at the National Energy Technology Laboratory (NETL). The Cornell study, published in a peer-reviewed journal, suggests that life cycle greenhouse gas (GHG) emissions from shale gas are 20%-100% higher than coal on a 20 year timeframe basis, especially considering that 70% of natural gas consumption is not used for electricity generation. The NETL study, presented in a talk at Cornell University and later posted on the NETL website, suggests, on an electricity-generation comparison basis, that natural gas base load has 48% lower GHG emissions than coal on a 20 year timeframe basis. The NETL comparison, however, does not single out shale gas, which is projected by the U.S. Energy Information Administration (EIA) to be the major source of natural gas supply growth going forward, or the overall emissions from natural gas-fired electricity generation, focusing instead on the more efficient base load combined cycle component. When the assumptions of the NETL study are examined in detail, and compared to the U.S. Environmental Protection Agency (EPA) 2009 emissions inventory for natural gas, as well as the likely ultimate production from shale gas wells, the resulting conclusions are not significantly different than the Cornell study. Shale gas full cycle greenhouse gas emissions are higher than coal when comparing both the existing electricity generating fleets and best-in-class electricity generation technologies for both fuels over a 20-year timeframe basis, and lower than coal on a 100-year timeframe basis. This has significant policy implications for utilizing natural gas as a “transition” fuel to a low carbon future in mitigating near term greenhouse gas emissions.  

Read the analysis:

 

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Read the main report: Will Natural Gas Fuel America in the 21st Century?

 

»  Download the complete report (PDF, 93 MB)

»  Download the plain-text version (PDF, 13 MB)

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Read the supplemental articles on agriculture, transportation, and health:

 

»  Download the supplementals (PDF, 1.5 MB)

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David Hughes

David Hughes is an earth scientist who has studied the energy resources of Canada for four decades, including 32 years with the Geological Survey of Canada as a scientist and research manager. He developed the National Coal Inventory to determine the availability and environmental constraints associated with Canada’s coal resources. As Team Leader for Unconventional Gas on the Canadian Gas Potential Committee, he coordinated the publication of a comprehensive assessment of Canada’s unconventional natural gas potential.

Over the past decade, Hughes has researched, published and lectured widely on global energy and sustainability issues in North America and internationally. His work with Post Carbon Institute includes: a series of papers (2011) on the challenges of natural gas being a "bridge fuel" from coal to renewables; Drill, Baby, Drill (2013), which took a far-ranging look at the prospects for various unconventional fuels in the United States; Drilling California (2013), which critically examined the U.S. Energy Information Administration’s (EIA) estimates of technically recoverable tight oil in the Monterey Shale, which the EIA claimed constituted two-thirds of U.S. tight oil (the EIA subsequently wrote down its resource estimate for the Monterey by 96%); Drilling Deeper (2014), which challenged the U.S. Department of Energy’s expectation of long-term domestic oil and natural gas abundance with an in depth assessment of all drilling and production data from the major shale plays through mid-2014; and Shale Gas Reality Check (2015) and Tight Oil Reality Check (2015), updates to Drilling Deeper. Separately from Post Carbon, Hughes authored BC LNG: A Reality Check in 2014 and A Clear View of BC LNG in 2015, which examined the issues surrounding a proposed massive scale-up of shale gas production in British Columbia for LNG export.

Hughes is president of Global Sustainability Research, a consultancy dedicated to research on energy and sustainability issues. He is also a board member of Physicians, Scientists & Engineers for Healthy Energy (PSE\Healthy Energy) and is a Fellow of Post Carbon Institute. Hughes contributed to Carbon Shift, an anthology edited by Thomas Homer-Dixon on the twin issues of peak energy and climate change, and his work has been featured in Nature, Canadian Business, Bloomberg, USA Today, as well as other popular press, radio, and television.


Tags: Coal, Fossil Fuels, Industry, Natural Gas