Energy use has increased throughout human history, rising tenfold since the twentieth century via a sixteen-fold increase in fossil fuel extraction (Smil, 2008). Fossil fuels have intrinsically linked themselves to today’s global economy and are essential for economic growth (Longwell, 2002; Leigh, 2008). Recent fears of “peaks” in the production of these non-renewable resources (e.g. Hirsch et al., 2005; Mohr, 2010; Patzek & Croft, 2010) have stimulated research and extraction of “unconventional” fossil fuels in order to offset these declines.
Whether an energy source is “conventional” or not relies upon technology and economics (Greene et al., 2006). Recent technological breakthroughs have allowed the extraction of shale gas, deposits of natural gas trapped in shale rock, via hydraulic fracturing. This process involves the injection of high-pressure fluids into shale rock formations underground, inducing fractures and releasing trapped gas deposits which travel to the surface (Hagström & Adams, 2012; Thompson, 2012; Hughes, 2013). Hydraulic fracturing, or “fracking”, is not a new process, but the scale of recent developments is unprecedented (Bierman et al., 2011; Guidotti, 2011).
With potentially huge reserves of shale gas now accessible (for US estimates see Engelder, 2011 and Hagström & Adams, 2012) proponents argue that shale gas should be used as a “transition fuel” between a fossil fuel economy and a renewable one (Charman, 2010). However, there are controversies surrounding the fracking industry, including whether shale gas is economically viable to extract (Hughes, 2013), issues with water contamination (Osborn et al., 2011; EcoWatch, 2013), health risks (Bamberger & Oswald, 2012), and its contribution to the greenhouse effect and global warming (Howarth et al., 2012). Should there be a complete ban on shale gas extraction via fracking, or a temporary moratorium to allow for a comprehensive assessment? Is shale gas a worthwhile investment, or should we be implementing cleaner, renewable alternatives?
There is no doubt that improvements in hydraulic fracturing and in the gas industry as a whole have allowed new access to large deposits of shale gas, with reserve estimates in the US alone ranging from fourteen trillion cubic metres (Charman, 2010) to forty-two trillion cubic metres (Engelder, 2011). However, accounting for US natural gas consumption of almost seven hundred billion cubic metres annually (CIA, 2011), this will represent between twenty and sixty years of consumption. This clashes with the claims of a one hundred year supply frequently asserted by some (Nelder, 2011).
A further issue is the energy that shale gas can contribute to society. The ERoEI (Energy Returned on Energy Invested) of shale gas is around 5-6 : 1 (Heinberg, 2012; Hughes, 2013), a worryingly small amount compared to a global natural gas ERoEI of 30 : 1 in the 1950s (Gupta & Hall, 2011). Further energy in extraction is required for extracting and processing the gas (Charman, 2010), and the water-intensive process could “threaten the viability” of shale gas (Kent, 2012). Claims that focus on financial costs rather than net-energy costs also ignore the perpetual capital needed to maintain shale gas extraction, called the “drilling treadmill” (Rogers, 2013) and at the moment extraction is dependent on financial subsidies to remain profitable (Hughes, 2013).
Additionally, the legitimacy of shale gas as a “transition fuel” can be called into question. Stephenson et al. (2012) find that the best available evidence in the industry does not support the transition fuel claim. Furthermore, the emissions and greenhouse gas footprint are typically larger than other fossil fuels (Howarth et al., 2011; Hultman et al., 2011; Howarth et al., 2012). The International Energy Agency (2011) itself admits that shale gas extraction produces higher life-cycle emissions than natural gas. Can a resource that is dirtier than other fossil fuels be called a transition fuel?
Although risks to environmental and human health are prevalent with any method of energy generation, hydraulic fracturing nonetheless presents a unique case. Health-wise, the cocktail of chemicals in fracking fluids present the risk of chronic health problems (Thompson, 2012) including those neurological and respiratory (Lauver, 2012). Bamberger & Oswald (2012) also found a correlation, albeit weak, between gas extraction activities and livestock mortality. However, due to the pace of shale gas extraction in the US, there are yet no well designed studies on the potential health risks it entails (Hultman et al., 2011). Although there are possibilities for safer water use (Jenner & Lamadrid, 2013), controversy remains over methane contamination of groundwater (e.g. Osborn et al., 2011 versus Etiope et al., 2013), although evidence abounds of methane leakage from poorly sealed well bores (Johnson & Boersma, 2013).
Further, regardless of its potential economic or social benefits, the issue remains regarding shale gas’ greenhouse gas emissions, where there is overwhelming consensus that its climate footprint is either equal or larger than other fossil fuels (Hultman et al., 2011; Hughes, 2011; Lior, 2011; Howarth et al., 2011; 2012; Jiang et al., 2011; Jenner & Lamadrid, 2013). Indeed, even a global transition to conventional gas would provide minimal respite for the climate (Myhrvold & Caldeira, 2012) – what point does shale gas then have?
Combine these issues with significantly downgraded gas reserves in the US (Blohm et al., 2012; Hughes, 2014), doubts regarding its possibility to bring energy independence (Vaughan, 2014), and scepticism regarding the replication of the US “shale gas revolution” in the EU (Johnson & Boersma, 2013), and you have a clear result – shale gas is far from being a long-term energetic panacea. Banning fracking and promoting investment in low-carbon technologies and electric grids would be an environmentally, healthier, and economically more sound move (Paltsev et al., 2011; Howarth et al., 2012; Jenner & Lamadrid, 2013) The Institute for Policy Research & Development (IPRD) for example, has already calculated that by using 1% of current fossil fuel capacity it would be possible to replace our “entire existing energy infrastructure with renewables in 25 years or less” (Schwartzman & Schwartzman, 2011).
It must be noted that shale gas extraction sites are heterogeneous regarding size, production rates, and safety, and so health hazards will vary between different areas (Jiang et al., 2011). Contrary to previous assertions however, shale gas extraction is still a hazardous method of energy extraction, with blowouts occurring in the Marcellus Shale (Zoback et al., 2010), and significant cancer and non-cancer risks affecting those living nearby shale gas extraction sites (McKenzie et al., 2012). Additionally, a historical perspective is required – shale gas was “elevated” as an alternative fuel in the US only after a string of catastrophes previously, including coal mine collapses, the Deepwater Horizon incident and the Fukushima meltdown (Jenner & Lamadrid, 2013). These high-impact/low-frequency events did well to remove coal, oil and nuclear power from the publically acceptable non-renewable energy portfolio.
It is also stressed previously that if shale gas is not an acceptable transition fuel (see Myhrvold & Caldeira, 2012; Stephenson et al., 2012), then what should be used in its stead? Some suggest the capital invested in shale gas extraction be diverted to smart electric grids (Howarth et al., 2012), or that shale gas can solve the problem of intermittency common with renewable energy (Carus, 2011). Despite this benefit however, shale gas extraction will simply reduce gas prices, which in turn will reduce the competitiveness of upcoming renewable technologies (Jenner & Lamadrid, 2013). An example is wind power in the US, where low gas prices have slowed or cancelled wind turbine construction (Greenwire, 2012; Wiser & Bolinger, 2012).
A more cynical outlook might proclaim that, despite the related health risks, low energy extraction, massive water consumption, and uncertain greenhouse gas footprint, fracking will continue regardless due to the consumption needs of the world and the “money to be made” (Rahm, 2011; Courtney, 2012). Can we afford to be complacent when the world we leave for our children and grandchildren is at stake?
The unviability of fracking is clear. There is no concealing the potentially huge resources of shale gas available for extraction, nor the (limited) economic benefits fracking can bring to a region via employment and energy independence. But evidence of groundwater contamination and potential health hazards reduce its viability. Add to this a larger climate footprint than coal, a low ERoEI, its water-intensive nature, and the economic problems shale gas has on truly renewable forms of energy, it becomes clear that fracking is neither economically or environmentally sustainable. It should not be pursued, and resources instead should be directed to truly renewable energy sources.
The author would like to apologise for those references which are unfortunately behind paywalls at the time of writing.