Holy Gas Seep, Batman

by Bill Chameides | April 21st, 2010
posted by Erica Rowell (Editor)

Permalink | 1 comment

While the world watches a volcano plume, Louisianans in Caddo Parish are fleeing a gas seep.

Technological Advances Open Whole New World of Fuel Potential

There’s a quiet revolution happening in the world of fossil fuels. Thanks to advances in hydraulic fracturing — often shortened to “hydro-fracking” or just “fracking” — huge amounts of once unrecoverable natural gas trapped in impermeable rock (known as shale) are now recoverable. (Details here [pdf]). As a result, in recent years our proved reserves and potential resources have jumped by leaps and bounds.

Vast reservoirs of this “shale gas” are believed to sit under large swaths of the United States. These formations include the:

Natural Gas: The Mother Lode That Will Keep Us Self-Sufficiently Energized?

Tallying up all that gas (along with other unconventional sources) has grown America’s potential natural gas resource from about 1,320 trillion cubic feet in 2006 to 1,835 trillion cubic feet in 2008, according to one analysis that puts shale gas at 33 percent of the potential resource. (Keep in mind that proved reserves of natural gas grew by about seven trillion cubic feet between 2007 and 2008.)

All that natural gas is equivalent to about 95 billion short tons of coal. That’s a whole lot when you consider we currently use only about one billion short tons of coal per year.

Not surprisingly, natural gas companies are gobbling up leases to drill through these shale formations, and big companies like Exxon Mobil are similarly playing Pac-man to smaller natural gas companies to become dominant players.

The implications of these new recoverable resources for America’s energy future are huge. The price of natural gas has fallen sharply, and with the projected abundance for decades to come, natural gas is suddenly competitive with coal. Increasingly, power companies are opting — or being pushed — to use natural gas instead of coal. Even here at Duke, we’ve decided to convert our coal-fired steam plants to natural gas ones.

This is without question good news for climate. Natural gas is a whole lot cleaner than coal — kilowatt for kilowatt, natural gas emits only half as much carbon dioxide as coal. Many argue that natural gas is the ideal bridge for the coming decade or so as we transition to even cleaner renewables.

Tapping Natural Gas Resources From Shale Not Problem-Free

But there are problems. Using these resources would not be such a great idea if their extraction exacted unacceptable environmental costs. When we think about natural resources, there is little that is more precious than clean drinking water. It would be a fool’s bargain on our part to become rich in natural gas but lose our water resource. And there’s the rub.

The process of hydraulic fracturing involves the injection of large amounts of water and toxic chemicals into the shale under high pressure to cause the rock to fracture and release the natural gas trapped in the interstices of the rock.

The first concern is that the process is water intensive [pdf], requiring two to five million gallons to develop a well. But of even greater concern is the safety of drinking water in and around drilling areas. All that toxic water and the toxic material it liberates from the shale can end up in the groundwater and eventually in drinking water — clearly not a good idea.

Concerns about the integrity of New York City’s drinking water have put, temporarily, the kibosh on some fracking projects in upstate New York.

Another threat to drinking water comes from the fact that fracking is a violent process: it can disturb the layer of rock overlying the shale, inadvertently liberating dangerous chemicals and gases that can contaminate drinking water.

Natural Gas Drilling Thought to Be Behind Recent Polluted Water

Could such a thing happen? Looks like it already has. The folks in Caddo Parish, Louisiana, have had to evacuate their homes because of seepage of natural gas into their wells.

It seems that, according to an article in the Wall Street Journal, Dallas-based Exco Resources Inc., a drilling company, accidentally “struck a pocket of gas much shallower than the company expected.” When gas was subsequently found in the local freshwater aquifer, local authorities began the evacuation. The WSJ reports that “tests found high levels of gas in dozens of local water wells, in some cases at levels that could lead to a explosion.”

Ironically, Louisiana’s Department of Natural Resources has designated April “Safe Digging Month.” Apparently not safe drinking month.

Suffice it to say, the water is undrinkable. The good news for the Caddo Parish residents is that Exco is reportedly paying for hotel rooms. Too bad they didn’t heed warnings that their drilling operations were moving too close to populated areas.

filed under: energy, faculty, fossil fuels, natural gas, water
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1 Comment

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  1. Cliff Westfall
    May 3, 2010

    Although I agree with much of your article, I urge you to reconsider whether shale gas is “unquestionably” a gain on the climate change front. Dr. Robert Howarth of Cornell University has argued that shale gas, when its cradle-to-grave emissions are considered, is slightly worse than coal. While his study is preliminary, what is already certain is that those who naively equate the emissions profiles of conventional natural gas and unconventional shale gas are making a large and environmentally significant error. This is because shale gas requires so much more energy to produce, and produces so many more emissions, that it logically cannot be equated with conventional gas on greenhouse indices. So far as I am aware, no one aside from Dr. Howarth has yet studied the greenhouse consequences specific to shale gas; instead, what we see is the constant invocation, even by well-meaning sources, of “clean-burning natural gas.”

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