I'll echo what Rick Katz said on natural gas in the US.
I have heard that from a nuclear-sympathetic specialist in the US (an ex-nuclear submarine naval engineer), from questions at a government briefing that Arthur Alexander and I did shortly after 3/11, and from my mom's hometown, where a showcase "clean" coal project
-- CO2 sequestration, to be built in an open-pit mine, the whole 9 yards ["everything"] -- got cancelled.
Capital costs are lower, and natural gas is
(comparatively) cheap despite NIMBY opposition to fracking and pipeline capacity issues.=