The Potential Downside of Natural Gas - by Matthew L. Wald, NY Times

Conventional wisdom, strongly promoted by the natural gas industry, is that natural gas drives down American emissions of carbon dioxide, by substituting for carbon-rich coal.  The climate stabilization plan announced by the Obama administration on Monday relies on that.  But in other ways, cheap natural gas drives emissions up.

When burned in a power plant, natural gas has a smaller carbon footprint than coal, and when it displaces coal, emissions decline.

But natural gas is starting to replace nuclear power, which can be seen as wiping out about 10 percent of the savings, because a reactor has a carbon footprint of nearly zero.

There are two other easy-to-see effects.  The fracking for oil that has opened vast new supplies of gas is producing much of it in places where there is no pipeline.  In those cases, the natural gas is burned off, or flared, because there is no way to ship it economically.

According to the Energy Information Administration, last year the producers flared enough gas to have produced 27 million megawatt-hours.  That pushed emissions up by 16.5 million tons, about 15 percent as much as the reduction in coal burning saved.

And some of the natural gas escapes unburned.  Its main component, methane, is a global warming gas and is far more powerful than carbon dioxide, although it does not persist quite as long in the atmosphere.  From 2007 to 2013 the increase in gas consumption added methane with a carbon dioxide equivalent of about 19 million tons. That would wipe out another 17 percent of the savings from displacing coal.  The number could be higher.

Also, natural gas is suppressing the development of new nuclear plants, experts say, leaving the country with an aging fleet of reactors.

The Potential Downside of Natural Gas - by Matthew L. Wald, NY Times