Natural gas is supposed to be the "bridge fuel." It's supposed to be the energy source that will lower the environmental impact of our global energy demands while we transition away from filthy, carbon-spewing coal and oil to our clean energy future of solar panels, wind turbines, or whatever the technology turns out to be. At least, that's the story if you listen to the conventional lefty wisdom out of D.C., or T. Boone Pickens, or America's Natural Gas Alliance, the industry's savvy media relations branch that seems to be sponsoring every other piece of energy-related content online, in print, and on television.
Here's an example: "Natural gas is the cleanest fossil fuel." That's the opening line of a memo by the Center for American Progress's CEO and President John Podesta, and a clear statement of liberal Beltway conventional wisdom. Podesta explains, "[natural gas] produces less than half as much carbon pollution as coal."
He's right, if we're talking emissions of carbon dioxide when the fuels are burned. But when you also consider the climate impact of extracting the fuels—as a new study out of Cornell (PDF) has just done—natural gas can be as bad for the climate as either coal or gas. This is mostly because during the extraction of shale gas a pretty enormous amount of methane is released, directly into the atmosphere. Methane is a notoriously strong greenhouse gas, capturing around 20 times as much heat as carbon dioxide.
While the study itself is still running through the peer-review gauntlet, it is slated to run in the upcoming issue of the Climatic Change journal, and The Hill received a pre-publication version. Lead author and Cornell professor Robert Howarth writes:
The [greenhouse gas] footprint for shale gas is greater than that for conventional gas or oil when viewed on any time horizon, but particularly so over 20 years. Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years.
To be clear, we're talking specifically about shale gas here—not the so-called "conventional gas," but rather the kind of natural gas that sits a mile underground, beneath layers of sandstone and limestone and can only, at present, be gathered through the controversial process of hydraulic fracturing (more commonly called, "hydrofracking"). This recent animated infographic from The New York Times is the best explainer I've seen about the whole fracking process.
Fracking for shale gas is the industry's biggest area of growth and expansion, and all of the glowing predictions of the abundance and low cost of natural gas are based entirely on this booming part of the industry.
Howarth emphasizes that the point of this study is not to steer us back to coal and oil.
The take-home message of our study is that if you do an integration of 20 years following the development of the gas, shale gas is worse than conventional gas and is, in fact, worse than coal and worse than oil. We are not advocating for more coal or oil, but rather to move to a truly green, renewable future as quickly as possible. We need to look at the true environmental consequences of shale gas.
The gas industry has responded quickly and dismissively to the Cornell study. Energy in Depth, the industry front group perhaps best known for their aggressive take downs of the Oscar-nominated Gasland documentary, immediately issued a statement, swiping Howarth aside as an activist and calling his a "bite sized" study. Expect more in the coming weeks. A forthcoming study from the Post Carbon Institute promises to provide a "comprehensive, systemic analysis of the role [gas] can and should play in our nation's energy future." From the tone of the Abstract, it's clear that this analysis will not be favorable for the so-called "bridge fuel."