A lucid and level-headed discussion of fracking

Excerpts from the best article I've read yet about fracking:

Supplies of natural gas now economically recoverable from shale in the United States could accommodate the country’s domestic demand for natural gas at current levels of consumption for more than a hundred years: an economic and strategic boon, and, at least in the near term, an important stepping-stone toward lower-carbon, greener energy.

Even at recent, somewhat higher prices, natural gas is now significantly cheaper than either diesel fuel or gasoline on an energy-equivalent basis: a little more than one-tenth the wholesale, spot prices of about $3 per gallon for those liquid fuels. Lower-priced natural gas has had important consequences for the U.S. economy...

Consumers have benefited directly from lower gas-utility bills, and industrial customers have benefited by switching fuels—as have chemical and other processors that use gas as a feedstock... The shift from coal to gas in the electricity sector has also yielded an environmental bonus—a significant reduction in emissions of CO2, because CO2 emissions per unit of electricity generated using coal are more than double those produced using gas...

The bulk of the natural gas produced from shale today is derived from wet sources: marketing of the liquid products (which command higher prices) justifies the investments. That means that the economic momentum of the shale-gas industry can be sustained for the long term only by decreasing production (ultimately causing prices to adjust—a process that may be under way as drilling diminishes at current prices) or by increasing sales of its product. Increased use of natural gas for transportation could provide an additional domestic market, taking advantage of the significant price disparity versus gasoline or diesel fuels (as noted above)...

To date, then, we can say conclusively that a shift to natural gas from coal has changed the U.S. energy system in ways that yield economic and environmental gains. But there are serious environmental challenges associated with freeing that gas from the shale and distributing it to consumers...

Drillers developing a well must take exceptional care to minimize contact between the wellbore and the surrounding aquifer—often the source of nearby residents’ fresh water. Serious problems have arisen in the past from failures to isolate the drilling liquids, including cases where well water used for drinking became so contaminated that human and animal health was threatened...

Care must be exercised to protect groundwater from spillage and to guard against potential leakage from the ponds. Moreover, the facilities to which the contaminated water is eventually transferred may be ill-prepared to deal with the challenges posed by its unusual chemical composition; for instance, conventional treatment facilities are not equipped to deal with radioactive materials—which under the circumstances could be transferred to the water bodies receiving the treated effluent.

Finally, careless drilling and production from fracked wells can result in fugitive emissions of methane from the shale below. Such inadvertent releases of methane could more than offset the advantages otherwise realized by reducing emissions of CO2 through substituting natural gas for other fuels.

There's much more at the Harvard Magazine link.  This article is refreshingly free of the polemic that typically characterizes discussion of this technology.