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Natural Gas: Palliative, Not a Cure

April 29, 2011

Plentiful and cheap natural gas is the Prozac of American energy policy. It may take the edge off of some of our worst symptoms in the near term. But it can also dull us to solving key long term and chronic problems, especially regarding climate change. And, as with any medication, there can also be some negative side-effects – some clearly remediable (methane leaks), and some (water and air contamination impacts from fracturing – or “fracking” – of shale to yield gas) still to be managed with sufficient rigor and transparency.

On the positive side, there is little doubt that cheap natural gas can help provide some environmental relief in the short term by lowering the cost of displacing older coal-fired electric generation. Natural gas power plants emit less than half of the CO2 per kilowatt-hour as do those powered by coal; the emissions reduction gains are even greater for conventional pollutants like smog and soot and for air toxics like mercury. True, upstream leaks of methane (a far more potent global warmer than CO2) are a source of greenhouse gas pollution that cuts into the climate advantages of burning natural gas. But these leaks can be virtually eliminated, and the gas industry needs to focus a lot more on fixing them, and less on insisting that we should only consider climate impacts over a full century (which de-emphasizes the importance of the methane leaks, relative to the CO2 advantages of gas over coal, because CO­2 lasts longer in the atmosphere).

But fuel switching alone simply is not a long-term solution for climate change. Recent reports by the National Academy of Sciences indicate that CO2 emissions are, effectively, permanent; half the carbon atoms emitted today will be in the atmosphere thousands of years from now. Because the atmosphere does not drain carbon quickly, much of the emissions from a “natural gas bridge,” unfortunately, will be with us for millennia. Given this carbon inertia, and uncertainty around the sensitivity of climate to CO2 (with really bad outcomes somewhat more likely than moderately bad ones), the only prudent approach is to pursue options that are zero-carbon. For example, gas-fired generation, like coal-fired generation, must be coupled with carbon capture and sequestration (CCS) to ensure near-zero emissions. Carbon capture from gas-fired generation has been commercially demonstrated in the US. Happily, it is also less expensive than carbon capture at coal plants at today’s natural gas prices.

The recent controversy surrounding a paper by Robert Howarth of Cornell that compares the life cycle emission of coal and gas power generation (arguing that natural gas may have a bigger climate footprint than coal due to leaks of methane), risks becoming a distraction from the main point. We need to develop and deploy greenhouse gas-free technologies today, regardless of the fuel source. My colleague at CATF, David McCabe, has provided a more detailed technical critique of the Howarth report. Some of his main points:

  1. Despite the paper’s flaws, it has brought long overdue attention to a critical climate issue: methane leaks from production of natural gas, oil and coal. These leaks are enormous sources of an extremely potent greenhouse gas, and they need to be eliminated – and this can happen right away. But let’s not lose sight of the fact that only with carbon capture and sequestration from all fossil fuels will we have the near zero-carbon electricity we need to protect our climate. We’ll need to use coal and gas for a long time around the world and we likely can’t develop and deploy renewables and advanced nuclear fast enough to avoid the worst effects of climate damage. It’s time to apply CCS at commercial scale.
  2. We can eliminate needless methane emissions from gas, oil, and coal extraction immediately at relatively low cost (some of these measures pay for themselves in months), making much of the coal-versus-natural gas methane leaks discussion irrelevant. EPA and the states should take appropriate actions to make this happen.
  3. Available data on these fugitive methane emissions are generally terrible, so this debate won’t be well-resolved for some time anyway. EPA needs to focus on improving that data, and the natural gas industry needs to stop fighting those efforts and help out. In the meantime we must begin eliminating the leaks we know about.

One last word on “cheap gas.” There is substantial euphoria right now over the “shale gale.” Otherwise sober-minded utility executives are staking their companies’ futures on cheap shale gas, and downplaying the need for policy changes to develop and deploy zero carbon energy. But serious doubts are being raised about the notion that a glut in shale gas will result in low gas prices in the long term. Putting aside potential environmental problems associated with “fracking” of shale gas, there is some evidence that current projections of low shale gas prices are based on early, high-yield production that in many cases declines rapidly, cross-subsidies from shale liquids, and the frenzied exercise of “use it or lose it” lease terms. In my almost 30-year career, I’ve witnessed gas-powered generation go from being legally forbidden, to low-cost savior, to high priced-delicacy, and now back again to apparently becoming America’s de facto energy policy. But history tells us that any energy or climate policy that makes an all-hands bet on a dominant solution is likely, in the fullness of time, to prove unwise.

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