Industry Challenges Study that Natural Gas 'Fracking' Adds Excessively to Greenhouse Effect
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By Richard Lovett of Nature magazine
In the calculus of global warming, natural gas is generally considered to be preferable to coal as a fuel. That's because, on a per-joule basis, burning methane, the primary constituent of natural gas, produces less carbon dioxide than burning coal.
But, earlier this week, the conventional wisdom was shaken by researchers from Cornell University in Ithaca, New York, who argue in a study to be published in Climate Change that, over a 20-year period, the use of natural gas extracted from 'gas shales', porous rocks that hold the gas in minute pockets throughout the rock, could be worse for the climate than coal. Their study also estimates methane releases from conventional gas production and transportation over a 20-year period, which are less than from gas shales, but could also be significant. However, gas shales are expected to represent the bulk of US production of natural gas in the future.
Culprit methane
The additional emissions from shale gas arise because the process of extracting gas from the shale, called hydraulic fracturing or fracking, releases some of the methane directly into the atmosphere. The rocks are shattered by high-pressure injection of water in order to release the methane more easily. According to the new study, by biogeochemist Robert Howarth and his colleagues, between 0.6 and 3.2% of the gas can escape to the atmosphere during this process. And methane is a much more potent greenhouse gas than carbon dioxide.
This study is guaranteed to be controversial. Even before the paper was officially published, the natural-gas industry was denouncing it as "bunk".
"This study lacks credibility and is full of contradictions," Russell Jones, senior economic adviser for the American Petroleum Institute, based in Washington DC, said on his organization's website. "The main author is an evolutionary biologist and an anti-natural-gas activist who is not credentialed to do this kind of chemical analysis."
There are several basic problems with the study, Jones told Nature: the 20-year time horizon is too short; state-of-the-art power plants fired by natural gas are considerably more efficient than the coal-fired plants; and the data is of poor quality.
Time horizon
Independent experts agree - in part.
The biggest concern is the 20-year timescale. "It's an outlier position," says Henry Jacoby, former co-director of the Program on the Science and Policy of Global Change at the Massachusetts Institute of Technology in Cambridge. His overall opinion is that the study is "very weak".
The time-horizon problem stems from trying to compare carbon dioxide emissions, the primary climate culprit in coal burning, with methane leaks.
Although methane is a powerful greenhouse gas it breaks down in decades, unlike carbon dioxide which persists in the atmosphere for hundreds to thousands of years. So although methane is more than 70 times more powerful at heating the atmosphere than carbon dioxide over a 20-year period, says Michael Wang, senior scientist on life-cycle energy and environmental effects of energy production at Argonne National Laboratory, Illinois, after 100 years it's only 25 times more potent.
Not everyone is so critical. Alan Krupnick at Resources for the Future, an economic think-tank in Washington DC, notes that much of the controversy is due to media headlines that cite the study as showing that natural gas is worse than coal.
"That's not exactly what the paper says," he notes. "It presents two numbers, one for a 20-year time period and one for a 100-year time period." Overlooked in the media fray, Krupnick says, is the fact that even on a 100-year timescale, coal and natural gas from shale came up roughly comparable -- still a serious blow to the latter.
But that's not the only issue.
Jacoby thinks that the industry is correct to cry foul over the study's failure to account for differences in energy efficiency between coal-fired power plants and those using natural gas. "Howarth is making the wrong comparison," Jacoby says. Instead of greenhouse emissions per joules of combustion energy, he says, what should have been used are emissions per kilowatt-hour of electricity produced -- a statistic that would have favored natural gas.
The methane leaks are still important, but none of the experts consulted for this article were sure how much methane is lost during production. Krupnick notes that some gas fields have been drilled so many times the rocks have been compared to Swiss cheese. "There are all these old boreholes that can be a pathway to the atmosphere."
"That's an area that deserves study," Jacoby agrees. "The blowback of fracking does bring up gas."
Lifetime study
But flawed or not, experts say, the study is a reminder that combustion isn't the only aspect of fuel production and usage that should be taken into account in discussions on emissions. "Sometimes we forget that the debate should always be done on a life-cycle basis," Krupnick says. "I think the Cornell study is very important to remind people that the whole life cycle is what matters, not just the immediate emissions."
As for concerns about data quality, Howarth is the first to admit it's a problem. "I fully agree the data weren't what one would like. I'm hoping this will help free up the logjam of industry refusing to turn over data, so that one can get a better handle than we've been able to do so far."
This article is reproduced with permission from the magazine Nature. The article was first published on April 15, 2011.
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11 Comments
Add CommentIs this a diversionary tactic by gas & oil?
Reply | Report Abuse | Link to thisIMO it's the environmental impact of fracking that is it's primary issue.
Btw, fracking in central Arkansas has been suspended following two unusual earthquakes occurring in the immediate vicinity, pending further study...
Fracking can do even more damage to underground drinking water.
Reply | Report Abuse | Link to thisI am sure that the earth quakes are related to deep drilling oil companies. Pumping salt water into deep faults, (trade secret???) to replace oil,... that is a different density, has to be causing huge problems.
Russell Jones, senior economic adviser for the American Petroleum Institute, based in Washington DC...really would expect him to be honest??? He's a big part of the "drill no matter what" problem.
Mining coal always releases methane to the atmosphere. Methane adsorbed by coal are vented to the atmosphere and monitored to prevent explosions. Very recently a coal mine explosion killed 29 at the Pike River Coal mine in New Zealand. What about Mercury?
Reply | Report Abuse | Link to thisHas the research taken methane releases at coal mines into account when they claim burning coal is less damaging? Who financed this research, surely not the coal mafia?
Using coal to generate electricity is less than 28% efficient
the last time I read about coal efficiencies. Beware of company claims, worked at 3M where are thermal oxidiser were claimed to by 98% efficient, not based on energy balance but what could be reasonably expected.
Any rational analytical exercise will tell any reasonable person gas is cleaner than toxic coal.
All building activity fractures strata of the mantle and alters underground water flows. BHP needs to restore its Appin underground coal mine site, South of Sydney, where the Appin river has disappeared underground through fractures in its bedrock.
We can see the level of honesty of this author by his claim that fracking uses water to open fractures in rock, when most of the complaints against fracking are related to the use of hazardous chemicals, like diesel, benzine, and other chemicals added to the water that is used for hydrolick pressure. If only water was used, there would not be the many wells contaminated or the surface contamination.
Reply | Report Abuse | Link to thisThen the main part of the article tries to downplay the methane heat trapping by claiming it falls to only 20 times as bad over years. 20 times worse is bad enough. Both coal and gas is dirty power and both need to be replaced with renewable power that does not produce greenhouse gasses or radiation emissions.
Reply | Report Abuse | Link to thisIt's not clear from the review if methane escape from conventional gas wells was included in the review of methane release in hydrofracked well operations in gas shale strata.
To alligatorhardt (#5)
Even if pure water were injected (and it emphatically is not) the production water from the shale strata brings dissolved solids and trace minerals to the surface. Production brine is a very salty solution which may also contain radioactivity, and varies in pH.
Production brine has been a disposal problem for oil and gas wells since long before the advent of the high-volume slick-water hydro-fracturing method (fracking).
Don't you think that Russell Jones, senior economic adviser for the American Petroleum Institute, is an idiot? Coal and natural gas is almost on the same footing when it comes to total destruction when it is extracted. Because of the fracking of natural gas, its destruction and pollution level when used is 400% greater than that of oil and coal.
Reply | Report Abuse | Link to this"Scientific Earthling", those 29 miners that was killed in that explosion was in West Virginia and Massey Energy is the company responsible for the damage in ripping and destroying 29 families.
It is a lot cheaper for the environment, human health and life just to switch over to clean energy like, Geothermal, hydro and hydrokenitic, ocean energy, solar and wind than it is to continue with fossil fuels...a lot cheaper and safer for humans and the environment.
Instead of wasting shale gas, apply measures to save energy for future generations. This will not please the energy lobby, but you can't please everybody.... It is in mankind's interest to reinstate an economy based on economies.
Reply | Report Abuse | Link to thisJames Davis: The Pike River Mine Disaster began on the 19 November 2010 in New Zealand. Here is a link: http://www.heraldsun.com.au/news/australian-miner-william-joynson-had-bags-packed/story-e6frf7jo-1225958885425
Reply | Report Abuse | Link to thisA short while ago we had a retired coal mining engineer listing all the problems associated with coal mining and the resulting environmental problems in this very forum. I hope you read what he had to say.
We defiantly need to move away from carbon based energy forms, but as a transition through methane seems a lot cleaner than coal. Remember the coal miners just vent it.
The basic problem is population, with 25% of the world population now Muslim, there is no likelihood of population control. We are now living Garrett Hardin's scenario in "Exploring new ethics for survival: The Voyage of the Spaceship Beagle" when those who believed in population control became extinct.
Simply put we too as a species are heading for certain extinction in the near future. Using gas will make our life a little more bearable, before the savages take over and ensure extinction.
One consolation: Perhaps whenever a species heads down the path of comprehending & controlling its environment it always ends up destroying itself. So unthinking, unbiased natural selection is perhaps to blame. While I write this, on the radio they are playing: The Tales of Hoffmann: Barcarolle sung in a melancholy voice by Joan Sutherland.
I am not sure what population growth in Muslim countries has got to do with the trade-offs of natural gas and coal. Please be aware that fertility rates are driven by mortality rates and economic conditions not religion. The most populous Muslim nation in the world Indonesia has a fertility rate of 2.13, Ireland 1.95 and the US 2.08.
Reply | Report Abuse | Link to thisSee www.gapminder.org for excellent data visualization of how fertility rates correlate to various factors and change over time. Select the "gapminder world" tab and change the bottom axis to "Children per Women (total fertility)".
And here is a short url to the above data visualization.
Reply | Report Abuse | Link to thiswww.bit.ly/gfF0SR
Homo sapien population levels drive the sixth extinction and observed climate change is one of the effects of our overpowering numbers on the biosphere. Biobalance has been lost. Feedback mechanisms no longer function.
Reply | Report Abuse | Link to thisWe are hypocrites and blame carbon dioxide for climate change. Your theory that mortality rates govern birth rates is obsolete. Example: Egypt 10M in 1950, 85M now. Bangladesh 30M in 1947 164M now. The birth rate for Bangladesh is supposed to be 2.3 Egypt 3.01. (calculate what the populations should be) I do not believe these fertility rate numbers. Population numbers are closer to the truth based on food consumption. In a BBC interview at the Copenhagen climate conference, the delegate for Bangladesh wanted the rest of the world to help Bangladesh by taking 5M citizens to ease overcrowding.
I have viewed Gapminder. I first try to determine who runs the organisation and what their agenda is, yes I am a skeptic, probably the result of a scientific education. I checked out fertility rate X axis and population growth rate Y axis Africa, the middle east and Indian subcontinent stand out. Did not need this chart to know that.
Your second graph graphically demonstrates the impact of science on life expectancy. You will observe the USA is the first to benefit (thank you science), Ireland (the laggard of Europe - result of religion) benefits later and finally Indonesia spirals rapidly to the top (aid & charity). This too is a problem, there should be no medical interventions to prolong life in a situation where population is increasing.
Well for what it is worth, I believe the situation is beyond resolution. The principal driver of population growth is religion and it will end in the extinction of our species in the near future. Lucky for us we shall not be around.