Tuesday, January 25, 2011

Climate Benefits of Natural Gas May Be Overstated


by Abrahm Lustgarten  ProPublica, Jan. 25, 2011, 10:36 a.m.
The United States is poised to bet its energy future on natural gas as a clean, plentiful fuel that can supplant coal and oil. But new research by the Environmental Protection Agency—and a growing understanding of the pollution associated with the full “life cycle” of gas production—is casting doubt on the assumption that gas offers a quick and easy solution to climate change.

Advocates for natural gas routinely assert that it produces 50 percent less greenhouse gases than coal and is a significant step toward a greener energy future. But those assumptions are based on emissions from the tailpipe or smokestack and don’t account for the methane and other pollution emitted when gas is extracted and piped to power plants and other customers.

The EPA’s new analysis doubles its previous estimates for the amount of methane gas that leaks from loose pipe fittings and is vented from gas wells, drastically changing the picture of the nation’s emissions that the agency painted as recently as April. Calculations for some gas-field emissions jumped by several hundred percent. Methane levels from the hydraulic fracturing of shale gas were 9,000 times higher than previously reported. [emphasis added]
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1 comment:

  1. This is a very incidental aspect to your natural gas story, but may be of interest to homeowners who use natural gas in their furnaces and fireplaces and other accessories.
    That nice 'wood-fire' look you get from a natural gas fireplace is achieved by 'starving' the combustion process, of primary air. A clean burning gas flame is blue, and the primary product of combustion is water. When the flame is oxygen starved the normal high efficiency of natural gas combustion (90++%)is reduced to about 40%. Of course the now yellow orange 'wood fire look' is laden with noxious exhaust, including a high volume of carbon monoxide. You do not want to be anywhere near the outside vent of these appliances when operating. So not only is it a poor use of a finite resource, but it is potentially dangerous.
    Most conventional(natural draft) gas furnaces operate at about 70% efficiency (btuh potential input compared to usable btuh output after combustion). The efficiency is dramatically improved (as high as 95%) with condensing furnaces but the main product of combustion, H20, is acidic and toxic, and usually is drained into municipal sewer systems.

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