With regulations targeting not only the traditional emissions such as sulfur dioxide and nitrogen oxide, but also new challenges like mercury and carbon capture, coal is not a cheap option for the time being. A number of new facilities that were formerly proposed as coal plants have switched to full natural gas or combined cycle over the last few years. One of the few remaining proposed coal plants, the Taylorville Energy Center, is likely to switch to gas.
The continued development of natural gas shale resources and an exceptionally warm winter have contributed to an overabundance of natural gas. The average spot price for natural gas in April 2012 was less than $2 per mmBtu, and prices may remain relatively low for a while. Gas prices in the U.S. could double in the next three years due to the gas demand as coal is replaced for gas in electricity. For the short-term, gas will likely stay far below $5. (Power Engineering, 7/12/2012)