Recent analysis by the largest grid operator in the US, PJM Interconnection, found that while proposals to reduce carbon dioxide emissions from fossil-fuel generating plants could increase wholesale electricity prices between $5.9 billion and $36 billion a year by 2013, the addition of 15 GW of wind energy in that same timeframe would reduce those prices by $3.55 billion to $4.74 billion. PJM used market models to simulate the impact of climate change legislation that places a cost on emitting CO2 through cap-and-trade or carbon tax policies. Coal fired generation accounted for about 66 GW on PJM's system at the end of 2007. The study's 15 GW figure for wind, which represents about a third of the wind generation in PJM's interconnection queue, would reduce CO2 emissions by nearly 35 million tons. Wind currently represents about 40% of all new generation projects proposed in the PJM region. "We're really excited by these findings," says Michael Goggin of the American Wind Energy Association. "What they're saying is that wind power can significantly reduce the cost of compliance with CO2 regulations." PJM serves 51 million people in all or parts of 13 states and the District of Columbia throughout the Mid-Atlantic and Midwest.