"Howarth’s study ignores what happens when gas and coal is converted into electricity. Instead, the study is solely focused on the emissions involved in production of each fuel source. This is flawed because modern gas power-generation technology is more efficient than that for coal, meaning that gas yields more electricity per unit of energy content."
By Kirsten Korosec | April 15, 2011
Natural-gas junkies advertise the fuel as a magic elixir that will painlessly usher Americans from dirty coal and foreign oil to a cleaner alternative. Now a new paper from Cornell University not only debunks these clean energy claims, but makes an audacious declaration: natural gas produced from shale is dirtier than coal.
Now, natural gas is far from a wonder fuel. But the Cornell paper’s big headline-generating conclusion — and it pains me to say this — simply can’t be taken seriously, thanks to inadequate data and a serious methodological problem. Which is not to say it’s wrong, just that we have no real way of knowing.
To read more: http://www.bnet.com/blog/clean-energy/coal-vs-natural-gas-why-an-amazing-new-study-doesn-8217t-prove-what-it-says/4830