The article could be shortened to new coal plants would be better than old coal plants and just as good or better than new gas plants.
Article

"researchers at Carnegie-Mellon University concluded that while the probability of reducing GHG emissions at least somewhat by replacing coal with gas in electricity generation was 100 percent, the substitution of natural gas as a transportation fuel actually carries a 10–35 percent risk of increasing emissions."

"Studies have tried to estimate the total emissions associated with gas using well-to-burner or “life-cycle” analysis. . . . many conclude that when natural gas replaces petroleum in transportation or heating oil in homes, the greenhouse gas benefits are slim to none. " 

"the Australian Council of Learned Societies in 2013 compared the efficiencies of a range of fuels, including conventional gas and shale gas, under a variety of conditions, and concluded that greenhouse gas emissions from electricity generation using efficient forms of coal burning were not that much more than from gas."