Look no further than Marcellus gas production for the most important, single reason why national gas prices have plunged, giving consumers a bonanza of savings, and causing gas generation to massively displace coal power. The Marcellus and especially Pennsylvania's production are the tipping point.
Don't believe it? See the following great Bloomberg piece by Naureen Malik: http://www.telegram.com/article/20120621/NEWS/106219795/1002/business.
In that piece, Fadel Gheit, the senior energy analyst for Oppenheimer and Company says: "The Marcellus single handedly changed the gas balance in the U.S...Marcellus Shale production is the reason why we have low gas prices."
By March 2012, gas production from the Marcellus had reached 6.3 billion cubic feet per day or about 10% of US daily gas production. Marcellus gas production alone supplied 62% of the gas needed for the 6 New England states, New York, New Jersey, Delaware, Pennsylvania and Maryland--the 11 Northeast and Mid-Atlantic states. That was enough new supply to crash prices, given the inadequate increases in demand to keep up with production.
At this point, the Marcellus gas production is bringing low gas prices not only to the Northeast 11 states but also across America, saving consumers many tens of billions of dollars, a blessing for the national economy.