On the other hand, the arguments for drilling into the Marcellus Shale are hard to ignore. Natural gas is by far the cleanest-burning fossil fuel, producing about half as much carbon dioxide as the energy-equivalent amount of coal. It also contains almost none of the heavy metals that frequently accompany coal. Moreover, our domestic reserves of natural gas are plentiful: The newly tapped deposits in the Marcellus Shale have helped to more than double the nation’s estimated shale gas reserves, from 23 trillion cubic feet in 2007 to some
60 trillion cubic feet in 2009.
The Department of Energy estimates that natural gas produces slightly more than one-fifth of all the electricity used in the United States, and that number is steadily rising. If production continues as planned, over the next couple of decades natural gas could supplant coal as the leading domestic fossil fuel, serving as a cleaner way to heat our homes and fire our electric plants. “We’ve got terrific natural gas resources,” says David Burnett, director of technology at the Global Petroleum Research Institute at Texas A&M University. “Our country is going broke, but the public refuses to realize how much money they’re spending on imported energy.”
Ernest Moniz, director of the MIT Energy Initiative and a former undersecretary of energy, sees natural gas as the energy source of choice until renewable sources like wind, solar, and geothermal become more commercially viable. “Natural gas truly is a bridge to a low-carbon future and could enable very substantial reductions in carbon emissions—as
much as 50 percent by 2050,” he says.
Assuming we can tolerate the collateral damage.
Created nearly 400 million years ago on the surface of a shallow inland sea, the Marcellus Shale formed as tectonic plates pushed up the landmasses that created the Appalachian and Catskill mountain ranges and buried the ancient sea under a layer of rock almost two miles thick. This compression process produced gaseous hydrocarbons that expanded and formed pockets and fissures in the rock—
formations that now hold natural gas.
For six decades gas outfitters have been devising increasingly elaborate ways to tap those buried reservoirs. In the late 1940s, the Halliburton Corp. of Houston pioneered the use of hydraulic fracturing to squeeze gas and oil from vertical wells in sandstone thousands of feet below the surface. Their technique involved pumping large quantities of water combined with fine sand and chemical additives into the ground. Through a bit of geologic alchemy, the injection shattered rock like a baseball hitting a windowpane, pushing natural gas and oil out of the rock and into the pipe when the water was pumped back out.
However, the technique proved difficult to use in shale deposits, which form in layers that are wide but shallow. Vertical drilling in shale hit too little surface area to suck up enough gas to make the effort worthwhile. “If you can’t turn the well so it goes along the shale formation and a lot of the well is exposed to the gas, you can’t get the gas out economically,” says Anthony Ingraffea, a hydraulic fracturing expert and professor of civil and environmental engineering at Cornell University.
In the 1990s, new drilling technology developed in Texas made recovering gas from shale far more efficient. The big innovation was a motor attached to the drill bit that allowed it to turn 90 degrees and bore horizontally for up to two miles. Boring parallel to the horizontal shale layers exposes much more of the gas deposits. Companies can also drill multiple wells in any direction from just one drilling pad, creating a honeycomb of tunnels miles beneath the surface that can siphon gas from hundreds of acres.
Next comes the even more difficult part. Typically, each well requires 2 million to 10 million gallons of water to extract the gas. As with conventional drilling, the water is mixed with sand to keep the fissures propped open, and with a cocktail of friction-reducing lubricants to make the water slick enough to slide through the pipes swiftly. Machinery has to pump the water at pressures high enough to send it anywhere from 3,000 feet to a mile down. It is not uncommon during drilling for a site to have at least 10 trucks with 1,000-horsepower pumps and for dozens of tanker trucks to make 800 to 1,200 trips transporting water if there is no on-site source.
Despite concerns that fracking could seriously deplete or contaminate local water supplies, in 2010 Pennsylvania issued more than 3,300 natural gas permits in the Marcellus Shale. Almost 1,500 wells were drilled, and thousands more are on the way. Other parts of the country with shale beds (“plays” in industry parlance), such as Wyoming, Colorado, Arkansas, and Louisiana, have experienced similar gas drilling booms.
To comprehend the long-term implications of hydraulic fracturing, you need to visit the region where gas drilling first boomed. It sits above the Barnett Shale, a formation that underlies 5,000 square miles surrounding Fort Worth, Texas. Large-scale fracking began here in 2002. There are now about 14,000 gas wells in the area, and it is there that the environmental fallout of fracking has been most pronounced. Residents have complained for years of contaminated water, poor air quality, and unexplained health problems such as headaches, dizziness, blackouts, and muscle contractions.
Drilling operations have turned some of Texas’s most affluent communities into industrial wastelands. In towns like Argyle and Bartonville, where drill rigs have been erected within a mile of schools, children complain of nosebleeds, dizziness, and nausea. Parents worry about the release of the cancer-causing chemical benzene in the air above gas fields from processing plants and equipment.
Fracking in the Marcellus Shale has
not been going on as long as it has in Texas, but residents have already begun to experience its dark side. Just ask Craig and Julie Sautner. When the cable technician and his wife moved to Dimock, an agricultural community of about 1,500 nestled in the rolling hills of northeastern Pennsylvania, they had no inkling they were sitting on top of a mother lode of natural gas—that is, not until an agent from Cabot Oil & Gas, a Houston-based natural gas producer, knocked on their door in May 2008. He offered them $10,000 to lease the mineral rights on their four acres, with the promise of even more in royalties if Cabot struck pay dirt. “You might as well sign it because all your neighbors are,” the man said, according to Craig. “If you don’t, you’ll miss out.”
In August 2008, the company started drilling less than 1,000 feet from the Sautners’ water well. By mid-September the family’s tap water was undrinkable. “I noticed the toilet water was murky, and when I used
the water in the sink in the kitchen, it was brown,” Craig recalls. He called Cabot Oil & Gas to complain, but representatives insisted there was no way that Cabot’s drilling process could have contaminated the Sautners’ well water. The gas deposits sit thousands of feet below water wells, the company told him. What’s more, the boreholes that channel the natural gas up to the surface are encased in steel and cement. But without admitting fault, Cabot installed a water filtration system in the Sautners’ basement, which now looks like “a science lab,” Craig says.
Tests conducted soon after by the Pennsylvania Department of Environmental Protection revealed that the Sautners’ water contained high levels of methane, the main component of natural gas. Although methane is not normally harmful to drink in concentrations below 10 milligrams per liter, it can evaporate from the water. If it collects in enclosed spaces like basements, it can become flammable and explode or suffocate those who inhale it. The Sautners, who have joined with a group of neighbors and filed a lawsuit against Cabot, worry that the methane could explode at any time. “My son asks every night,” Craig says, with no small measure of gallows humor, “ ‘Do you think we’ll wake up in the morning?’ ”