Coal's decline: Driven by policy or technology?

The political rhetoric would have it that the dramatic decline in the use of coal in the U.S. since 2008 has been a result of 'Obama's war on coal' - that is, the EPA's Clean Air rules. But the data say otherwise. Rather, enabled by shale drilling, cheap natural gas is outcompeting coal markedly. An analysis that includes gas's techno-economic pluses concludes the trend will continue.