More False Solutions | Shale Gas
Hamilton: Proceed with caution on shale gas
Jul 26 2010
By Tyler Hamilton Energy and Technology Columnist
Movie buffs might not describe the sci-fi action movie Alien vs. Predator as a classic, but the 2004 film offers enough entertainment to liven up a lazy Sunday afternoon.
What I liked about the movie, and this is a common theme with this genre, is that your enemy can quickly become your ally when you’re both facing an even more dangerous adversary. In this movie, the only surviving human in an Antarctic base station feels compelled to team up with a green-blooded Predator to defeat a really badass Alien queen.
This is how many people, including environmentalists, view natural gas. It’s a fossil fuel, so from an air pollution and climate-change perspective, it’s something we should be getting away from—eventually.
But natural gas, when you burn it, emits roughly half as much carbon dioxide compared to burning coal and far fewer smog-causing pollutants. In this sense, natural gas is being viewed as an ally in the fight against climate change – and coal.
Environmentalists, while acknowledging we have to reduce natural gas use over the long term, see natural gas as a “transition fuel” that moves us away from coal and toward more renewable-energy sources.
The petroleum industry seems content to ride the trend. “The majors’ dash for gas is a bet on demand and climate-change policy,” wrote The Economist earlier this month. “The future, they believe, will be less oily and a lot gassier.”
This, no doubt, has also whipped up excitement around unconventional natural gas, particularly North America’s apparently vast and largely untapped fields of shale gas. To extract shale gas requires horizontal drilling and the hydraulic fracturing – or “hydrofracking” – of shale rock so that pockets of methane can escape into a collection well.
New drilling and hydrofracking technologies have dramatically reduced the cost of shale-gas development, changing the fortunes of the natural-gas industry almost overnight.
“The ‘shale gale’ sweeping across North America the past few years has more than doubled the size of the discovered natural gas resource in North America – enough to satisfy more than 100 years of consumption at current rates,” according to a recent analysis by IHS Cambridge Energy Research Associates.
This is generally touted as a good thing. “Unconventional gas, and particularly shale gas, will make an important contribution to future U.S. energy supply and carbon dioxide emission-reduction efforts,” concluded the Massachusetts Institute of Technology in a study released in June. Study co-author Ernest Moniz went so far as calling natural gas “crucial” to making substantial reductions in carbon emissions.
Me, I think this emerging love affair with natural gas is worrying. Seems we’re getting a little too comfortable – and moving too fast—with the Predator.
For one, if you drill into the numbers this claim of “more than 100 years” of supply appears to be a gross exaggeration. Some petroleum geologists say the “probable” supply is less than 20 years and that shale gas represents maybe seven years of that supply.
Second, it’s no secret that shale gas is to the natural gas industry what the tar sands are to the oil industry – that is, much dirtier to extract. Water is one hot-button issue. Huge volumes of water are required as part of the hydrofracking process. The water is mixed with toxic chemicals and injected under pressure into a well, forcing cracks in the shale rock.
How, and to what extent, this toxic brew can escape into rivers and aquifers is the subject of intense debate. The U.S. Environmental Protection Agency is currently studying the risks.
Folks like Robert Howarth have a potentially bigger concern. We don’t really know much about the greenhouse-gas emissions that result from shale-gas extraction processes, says Howarth, a professor of geochemistry at New York’s Cornell University.
What he’s talking about are fugitive emissions – methane that leaks out of the ground, equipment and natural gas pipeline infrastructure. True, says Howarth, high-efficiency natural gas plants emit roughly half the carbon dioxide of a coal plant, but this assumes all of the gas is actually burned.
How much escapes before it gets to the power plant? “There isn’t much information out there, even for conventional natural gas,” says Howarth. “I find that surprising given how important it is. We ought to know.”
Over a 100-year timeframe, methane is considered to be 21 times more potent than carbon dioxide as a greenhouse gas. During methane’s first 20 years in the atmosphere, however, it’s more like 72 times more potent.
There are many points where methane can escape. For example, the water used for hydrofracking is under pressure and gets saturated with methane before it returns to the surface. “When it comes back up it will degas to the atmosphere,” says Howarth.
There’s also the action of hydrofracking itself. “Once you start fracturing the shale you open up fissures,” he says. “It means you’re going to be allowing methane to escape to the surface faster than before.”
This excludes fugitive emissions that may result from leaky equipment and pipelines. Howarth has done some preliminary calculations, based on the limited information out there, and estimates that shale gas – from extraction to pipeline transport to combustion in a power plant – emits more greenhouse gases than the mining, transport and combustion of coal.
He’s hoping to complete a more detailed paper in September and get it published in a peer-reviewed journal early next year. Until the issue is studied more closely, he thinks it’s naïve for environmentalists and politicians to position natural gas, which is increasingly coming from shale fields, as our climate-change saviour.
Just a 2 per cent leakage rate out of all natural gas production could put more greenhouse gases in the atmosphere over the next two decades than burning the other 98 per cent.
Sure, the methane will become less potent in the atmosphere over a long period of time, but if we’re hoping to avoid any climate-change tipping points over the next 20 years, then relying too heavily on shale gas at this point in the game would seem unwise – if not straight out stupid.
“It’s just a bad idea,” says Howarth.
Tyler Hamilton writes weekly about green energy and clean technologies. Contact him at tyler.