Beginning in 2005 natural gas production in the United States has risen sharply. This has caused natural gas prices to fall, lowering energy costs and expanding natural gas consumption at the expense of coal. The new natural gas also fuels the turbines that serve as backup power for new wind and solar power installations.
The source of these events is the rapidly spreading use of hydraulic fracturing (fracking) to extract natural gas from shale. This technique entails the injection of water, sand, and small amounts of chemicals deep underground to fracture the shale and release the natural gas it contains. Concerns have arisen, however, over the potential adverse effects of fracking—events said to range from groundwater contamination to earthquakes. Recent research helps us understand whether we should—or should not—fear fracking (Hitzman et al. 2012, Moniz et al. 2012, and Fulton et al. 2011). There are several issues.
Water usage—A typical shale gas well requires about 4 million gallons of water to fracture the rocks and get the gas flowing at commercially profitable levels (Moniz et al. 2012). This sounds like a lot of water, but it is less than a typical golf course uses in two weeks. Roughly 80 percent of the water used in fracking a well stays underground. The rest comes back up as return flow and must be cleaned before it can be safely consumed or used in agricultural or commercial operations. The cleanup is not cheap, but it is a routine undertaking, in part because most of the chemicals used in fracking are those that many people have around the home, including those found in deodorants, glass and other cleaners, and even chewing gum and cosmetics.
An additional complication for fracking in some areas is that a variety of contaminants, including chloride and bromide salts, are brought from underground to the surface in the return flow water. Historically, this contaminated wastewater has been too costly to treat, so it has been re-injected deep underground into separate EPA-regulated wells designated for this purpose. The costs of cleaning such contaminated water are falling rapidly, however, and a new industry has emerged in the last few years: cleaning and recycling this water for use in fracturing other wells.
Groundwater contamination—Fracking wells are drilled vertically for thousands of feet before they turn horizontally to go into the shale, fracture it, and retrieve the gas. The fracking itself occurs far from any water sources, but when the gas comes up the vertical pipe it is possible for some of it to escape the pipe. If the vertical well shaft passes through a surrounding aquifer from which people draw their water, leaking gas can contaminate the water.
Gas that escapes the pipe is gas that cannot be sold. Drilling companies prevent leaks by injecting cement into the well, encasing the pipe and sealing the gas off from any nearby aquifer (or indeed anything else). Leaks do happen, but the issue here is not fracking, per se. Gas can escape from virtually any gas or oil well. The key to preventing this is careful well construction. As long as standard drilling practices are adhered to, groundwater contamination is extremely rare (Moniz et al. 2012). What of the Internet film clips that show flaming water coming out of kitchen spigots? Well, naturally-occurring methane in groundwater supplies is common in areas such as Pennsylvania lying over fossil fuel reserves. Setting one’s water on fire has long been a party trick where the natural methane concentrations are high enough to be readily flammable.
Earthquakes—Much has been made about the potential for fracking to cause earthquakes. As long as 90 years ago, scientists realized that conventional oil and gas production can cause small quakes. More recently, it has been found that the production of geothermal power also induces earthquakes. Even the impoundment of large amounts of water behind a dam can put enough stress on the earth to cause earthquakes. According to the National Academy of Sciences (Hitzman et al. 2012), however, the chances are negligible that fracking would prompt an earthquake of a magnitude that would harm humans or property.
Air pollution and greenhouse gases—Coal-fired power plants are a major source of carbon monoxide, nitrogen oxides, sulfur dioxide, and particulate matter. Compared to coal, burning natural gas generates only 20 percent as much carbon monoxide and nitrogen oxides, and virtually no sulfur dioxide or particulate matter. Fracking is displacing coal, so it is reducing air pollution.
Methane is regarded as a potent greenhouse gas. It is also the principal component of natural gas, and all natural gas production causes the release of some methane. Fracking does seem to cause a higher rate of release of methane into the atmosphere, however. Balanced against this is the fact that burning natural gas generates about only half as much CO2 per unit of energy as burning coal does. Replacing coal with natural gas—fracked or otherwise—likely reduces overall greenhouse gas emissions by about 50 percent (Fulton et al. 2012).
Fracking entails tradeoffs, as do all activities. But the purely economic benefits of the process are clear. It even appears, on balance, as though the environmental benefits outweigh any environmental downsides. So, although some commentators have characterized hydraulic fracturing as being “all fracked up,” it seems much more likely at this point that it is, in fact, a “fracking good deal.”
Fulton, Mark, et al. 2011. Comparing Life-Cycle Greenhouse Gases from Natural Gas and Coal. Worldwatch Institute, DC.
Hitzman, Murray W., et al. 2012. Induced Seismicity Potential in Energy Technologies. National Academy of Sciences, DC.
Moniz, Ernest J., et al. 2012. The Future of Natural Gas. Massachusetts Institute of Technology, MA.
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