U.S. Investigates Safety of Natural Gas "Fracking"
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By Nicola Jones of Nature magazine
When audiences saw dramatic scenes of people setting their tap water on fire in the Oscar-nominated documentary Gasland, hydraulic fracturing, or "fracking," was thrown into the spotlight. The technique, in which high-pressure fluids are pumped into shale formations to fracture the rock and force out natural gas, has been accused of releasing methane into well water (hence the flammable water), polluting groundwater with toxic chemicals and even causing earthquakes.
On May 5, U.S. Department of Energy head Steven Chu set up an expert panel to make recommendations on how to improve the safety and environmental performance of fracking. Several areas, including the state of New Jersey, the city of Buffalo, New York, and the Canadian province of Quebec, have recently banned the practice or issued moratoriums on new development. On May, 11 the lower house in the French parliament voted to ban the technique, with the upper house expected to follow suit next month--although the proposed ban does include an exemption for research on the technology and its environmental impact. Nature checks out how valid the accusations are and how the technique is being regulated.
Why frack?
Vast quantities of natural gas lurk in shale rock formations deep underground: shale reserves are thought to contain 187 trillion cubic metres of natural gas. This adds about 40 percent to previous estimates of global recoverable gas resources that don't include shale reserves. The largest known reserves are in China, the United States, Argentina and Mexico, in that order.
To get the gas out, companies drill down into the shale, then sideways through the deposit. This approach took off in the 1980s, with U.S. production increasing more than ten times from 2000 to 2010. The U.S. Energy Information Administration estimates that shale gas makes up 34 percent of the nation's natural-gas production, rising to 47 percent by 2035.
Does fracking release methane into tap water?
Many people living near fracking sites have complained of bubbly or flammable water. Methane can leak into wellwater totally naturally. A study in the May 9 issue of Proceedings of the National Academy of Sciences (PNAS) reported a link between methane in well water and fracking operations in northeastern Pennsylvania and nearby areas of New York state (see "Methane threat to drinking water"). The authors concluded the methane was probably coming from leaky well pipes, which would mean an easy fix. But it was also possible that the fracturing process created cracks that let methane seep upwards into groundwater.
Methane doesn't make water undrinkable--but the gas can cause asphyxiation or explosions in confined spaces. Some researchers have called for studies into the possible health effects of breathing in methane.
Does fracking pollute groundwater?
Fracking fluids contain many compounds, including sand, ground-up walnut shells, salt, citric acid, benzene--a known carcinogen--and lead. Some of these help to keep the fractures propped open; some reduce water surface tension and keep particles suspended in the fluid even at high pressures; and some are biocides that stop bacteria from clogging up the well.
A U.S. Congressional report released in April showed that the 14 most active hydraulic fracturing companies in the United States together used nearly 3 billion liters of fracking fluid, not including water. The products contained at least 29 chemicals that are known or possible human carcinogens.
The question is what concentrations these chemicals are used in, and whether the substances (or natural hazards such as radioactive radium present in the rock) escape the drilling area and contaminate water supplies--either by leaking out from the drill site, or through improper disposal. An investigation by The New York Times revealed worrying levels of radioactivity in fracking wastewater going to rivers in Pennsylvania. The PNAS study, however, found no evidence that fracking fluids were leaching into wells. The US Environmental Protection Agency launched a study of these questions in March last year--but the agency doesn't expect results to start coming in until the end of 2012, with a report scheduled for 2014.
Aren't there regulations in place to prevent pollution?
Fracking is exempt from the US Safe Drinking Water Act, although the U.S. House of Representatives did introduce a bill in March to close that loophole. The bill seems to have strong Democratic support, but it is unclear how popular it will prove overall.
In November last year, the US Department of the Interior said that it was considering requiring all US companies to reveal the chemicals used in their fracking fluids. Several states have already passed laws along these lines--Colorado has mandated fracking-chemical disclosures, for example, and Texas is now working on a similar rule.
Are efforts being made to reduce pollution?
Halliburton, a company based in Houston, Texas, that supplies products and services to energy companies, has developed CleanStim--a fracking fluid made with ingredients "sourced from the food industry" (though the company warns that the product should not be considered edible), along with water-treatment systems and more. And at least one company--Poseidon Sciences in New York--is investigating biocides that can't escape a well, such as selenium-coated sand particles.
Does fracking cause earthquakes?
There have been no cases in which hydraulic fracturing is suspected to have triggered a quake. But the way in which many companies get rid of their drilling water--by pumping it into disposal wells--definitely can. In Colorado in the 1960s, injection wells were linked to quakes as large as a magnitude-5 one that caused damage in Denver, says Scott Ausbrooks of the Arkansas Geological Survey in Little Rock. Today, injection wells in Arkansas have been shut down while geologists examine a possible link to a recent swarm of quakes, in an area that Ausbrooks says could potentially trigger a magnitude 6. There are thousands of injection wells across the country, says Ausbrooks, and only a couple have been linked to seismicity.
Fracking itself is a gentler activity. "You are generating micro seismic events, but the amount of energy is minute. We had a [seismic] station half a mile from where they were fracking and we couldn't detect it," Ausbrooks says.
When will the energy department release its results?
The panel will report on any immediate steps that would improve safety and environmental protection within 3 months; its full consensus advice will take 6 months. The panel is not providing media interviews.
This article is reproduced with permission from the magazine Nature. The article was first published on May 12, 2011.
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6 Comments
Add CommentI appreciate this sober and informative article. As someone who lives on the Marcellus Shale, many friends and neighbors have gone ballistic over hydrofracking. To some extent I think they're right. It's crazy to exempt the procedure from the clean water act. It's unacceptable that the fracking chemicals are not disclosed and often not correctly disposed of. And it's disingenuous that gas companies can deny that they've messed up some wells and owe them compensation.
Reply | Report Abuse | Link to thisHowever, the hysteria around here has gone far beyond these reasonable points. People are talking about entire aquifers being polluted by hydrofracking, which is geologically absolute nonsense. But most disappointing of all is the NIMBYism that I see all around me. Everyone knows that there is no perfect source of energy. For me to support widespread hydrofracking, I only need to be convinced that it's substantially better than our worst widespread energy source. And once the issues mentioned above are cleared up, it will be. That's not saying much, because the worst source of energy is clearly coal, and coal is abysmally bad. Hydrofracking is merely sort of bad, and dangerous when improperly regulated, but it's miles from being coal-bad.
I'm ashamed to live in a country where half of our electricity comes from coal, and that share is projected to *grow* for the next two decades! That's the real tragedy. We have a much better source of energy under our feet and tapping it could do a lot of good for the country as a whole. But because it's under *our* feet, we're unwilling to step up and take one for the team. We prefer to sentence some poor West Virginians (directly - and everyone on the planet indirectly) to endure something much worse. This is what makes me sad. Massachusetts has great wind resources, but they don't want to share them with us, and for petty reasons. Our blessing is gas, and while we have a much better reason to be weary, let's not kid ourselves and pretend that it's better to leave that stuff in the ground and let other people's backyards be destroyed.
As our ancient ancestors knew before they learned to control fire, in temperate conditions people can survive with no combustible fuel whatsoever, but no on can survive without potable water.
Reply | Report Abuse | Link to thishttp://www.elibrary.dep.state.pa.us/dsweb/Get/Document-77433/5600-FS-DEP2690.pdf
Reply | Report Abuse | Link to thisis a pamphlet on venting methane from water wells. This has been a problem way before the fracking technique was developed, so ignitable water can't be exclusively due to gas drilling in the neighborhood.
I have it on the authority of one of my neighbors, who was instrumental in developing the fracking technique, that the chemicals are 'propents', or finely ground minerals that hold the cracks open and detergents to aid in the extraction from the stratum. Hardly sounds life threatening.
This entire issue has been hyped beyond all sense of proportion. I was glad to see that this article at least took a measured tone. So far there has been nothing beyond scattered anecdotal evidence of harm from fracking. As the article points out, some incidents of gas in water could be from faulty well casings - which has nothing to do with fracking. And, this is something which has always occurred naturally.
Reply | Report Abuse | Link to thisWe need to get fracking right very soon because shale gas deposits are widespread throughout the world and this fuel could potentially save us from the horrible damage coal consumption causes. It is possible that this gas can be extracted much more cleanly, but exempting fracking from the clean water act is just being lazy and favoring the well-connected and financed drilling lobby. If we fail to make fracking safe, we will just be trading clean drinking water for dirty gas.
Reply | Report Abuse | Link to this<a href="http://www.FrackingNaturalGas.com">Fracking Natural Gas</a> is quite a heated debate I have realized. www.FrackingNaturalGas.com has both sides of the story trying to get some good debate going so we can get to the bottom of this issue. We all want to be good stewards of mother earth. We need to remember to temper our thoughs with caution after all money is the root of all evil.
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