Natural gas is expected to double its share of the energy market, according to a study done by the Massachusetts Institute of Technology and reported on here by the NYT. The article: "The increase, the report concluded, will come largely at the expense of coal and will be driven both by abundant supplies of natural gas — made more available by shale drilling — and by measures to restrict the carbon dioxide emissions that are linked to climate change."
For more on the report, including links to a copy of the full report and related press release, see here (MIT).