Earth & Environmental Science

Fracking β€” the pros and cons

What’s really going on beneath our feet when we use fracking to extract natural gas from deep underground?

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The Author

Scott A. Elias, PhDDr. Scott A. Elias is Professor of Quaternary Science in the Department of Geography of Royal Holloway, University of London, specializing in environmental biology. His chief research focus concerns the reconstruction of past environmental change and the response of animals and plants to those changes during the last million years.

Reference Modules on ScienceDirect

Recently, he became Editor-in-Chief of the upcoming Elsevier Reference Module in Earth Systems and Environmental Sciences, which will contain more than 3,800 peer-reviewed articles from Elsevier reference works, many on issues related to the state of the planet's health. The module will be hosted on ScienceDirect, a scientific database containing more than 11 million full-text journal articles and book chapters. [divider]

Fracking: What is it?

Fracking for shale gas has become big business, transforming the US energy landscape. But is it safe?This is a fracking well in the western United States. (Brooks, M, "Frack on or frack off? Can shale gas really save the planet," New Scientist, August 10, 2013)

Shale gas is methane trapped in tiny pockets in shale rock formations. In order to extract the gas, engineers drill shafts down into the shale, most often with many radiating horizontal shafts that feed into the vertical shaft. Engineers drill vertical shafts down to great depths, then they drill radiating horizontal shafts that feed it. Then they force hydraulic fluids into the rock to fracture the shale and open the pockets of gas, releasing it to flow to the surface.

The term "fracking" is short for "hydraulic fracturing." Over the past 10 to 15 years, the number of fracking wells has expanded rapidly in the US, liberating increasing amounts of methane.

What are the benefits?

So much natural gas has been extracted through fracking in recent years that US carbon emissions are actually falling. This is partly due to the economic recession since 2008, but the US Energy Information Administration reckons that just less than half of the fall in emissions is due to the replacement of coal burning with shale gas for electrical energy production. It would seem that shale gas, which occurs in shale deposits around the world, is in a perfect position to replace coal in power stations. Already more than a third of natural gas burned in the US is coming from fracking wells, and shale gas is now cheaper than coal in the US.President Obama recently praised the US natural gas boom in a speech on climate change, crediting it with delivering cleaner energy. Many have described fracking as the bridge between the carbon-based energy systems of the past and a cleaner, greener future.

What are the risks?

In 2013, an estimated 250 billion cubic meters of natural gas will be brought to the surface by fracking in the US. ( Brooks, 2013)

If fracking was just a new-fangled way of tapping natural gas sources, it would be welcomed by most people as a cheaper, cleaner alternative to oil and coal. The problems lie in the method of extraction.In order to get the gas out, a witch's brew of toxic chemicals has to be pumped into the shale at high pressure. More specifically, this is a mixture of water, sand, lubricants, poisons to keep bacteria and other microorganisms from clogging the pipes, and hydrochloric acid to dissolve the excess cement in the pipes (Brooks, 2013). If these fluids stayed far underground, they might not damage the human environment. The problem is that they find their way back to the surface through accidents at well heads, well blowouts, backflow of fluids to the surface, and leaks throughout the system. Altogether, more than 650 products containing chemicals with potential cancer-causing properties have been used in fracking (Balaba and Smart, 2012).

One would think that a country such as the US would have laws to protect the environment from toxic pollutants like these, but unfortunately the current laws are full of loopholes when it comes to fracking. For instance, an exception to the Safe Drinking Water Act is made for toxic chemicals injected into wells during hydraulic fracturing. An exception to the Clean Water Act permits temporarily stored waste water from fracking facilities to go untreated.

Other exemptions to US environmental safety regulations mean that fracking well operators are not obliged to report annual releases of toxic chemicals from their wells (Centner, 2013).Finally, the government does not require well operators to disclose the chemical contents of the fluids they use in the fracking process. These are considered trade secrets. It seems ironic that these companies do not have to disclose the contents of their fracking chemicals, when the manufacturers of household cleaning products must disclose every detail of their contents (Lauver, 2012).

Fracking wells have been developed across the country, with highest density in Texas, Wyoming, California and Pennsylvania. (Source: US Environmental Protection Agency, 2012)The Obama administration is proposing a new set of fracking rules, and their initial proposal has received an enormous number of comments from the public (more than 175,000 responses). The new set of rules only cover fracking on public lands, but the administration hopes that these rules will be adopted by individual states for use on private lands as well.

The rules set standards of well integrity and management of polluted water that flows back to the surface. Groundwater pollution is another serious concern, but results of an EPA study on that threat are not expected before 2016. In the meantime, thousands of new fracking wells are springing up all over the country.

Related story

Read Dr. Elias's previous Elsevier Connect article: "Climate change's silver lining"[divider]

References

Balaba, RS, Smart, RB, "Total arsenic and selenium analysis in Marcellus shale, high-salinity water, and hydrofracture flowback wastewater,"

Chemosphere89, 2012.

Brooks, M, "Frack on or frack off? can shale gas really save the planet," New Scientist, August 10, 2013.

Centner,  TJ, "Oversight of shale gas production in the United States and the disclosure of toxic substances," Resources Policy 38, 2013.

Lauver, LS, "Environmental health advocacy: an overview of natural gas drilling in northeast Pennsylvania and implications for pediatric nursing," Journal of Pediatric Nursing 27, 2012.

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