Whether the current boom in hydraulic fracturing (“fracking”) for shale gas is a short-lived bubble or a natural gas revolution, it threatens to increase pollution, destroy habitat, and keep America hooked on a “bridge fuel” to nowhere.
Recent adoption of horizontal drilling and hydraulic fracturing (“fracking”) has precipitated a global shale gas drilling boom. Fracking fluid is a mixture of chemicals, water, and sand that is injected under extreme pressure into a shale formation, opening cracks in the shale that release the natural gas trapped in the rock. Shale gas deposits are widespread in North America, Europe, Asia, and Australia. In the United States, the Marcellus Shale running from New York to West Virginia is the epicenter of the shale gas rush. The Barnett Shale of Texas, the Hayesville Shale in Louisiana, and the Fayetteville Shale of Arkansas are other important U.S. shale gas deposits. Many landowners and rural communities see shale gas development as an economic windfall.
U.S. conventional natural gas production peaked in 2001 and was thought to be in terminal decline before the fracking boom, which has reversed the production trend and prompted the U.S. Energy Information Administration to increase its estimate of recoverable domestic natural gas reserves. In 2009 shale gas provided 14 percent of U.S. natural gas supplies and is officially projected to grow to 46 percent by 2035. But some energy experts think that is unlikely because of high per-well costs and steep decline rates in shale gas wells.
As with conventional gas production, shale gas development entails clearing land for drill pads, access roads, and pipelines. But unlike conventional gas production, fracking consumes copious quantities of water—up to several million gallons per well—which may lead to intense competition for water in more arid parts of the country. Furthermore, the drilling fluid and wastewater that remain after fracking are full of largely undisclosed chemicals, some toxic, that may contaminate groundwater if spilled or leached into nearby streams.
While natural gas has been viewed as the least-polluting fossil fuel, analyses of the life-cycle greenhouse gas emissions of shale gas production by some scientists have suggested that it is not much better than coal power, largely due to increased methane release during drilling and transmission. If confirmed, this undermines the idea that shale gas is a less-polluting “transition fuel” toward renewables.