SHOVELED ASIDE: Coal, which has generated about half of the nation’s electricity for much of the last century, is declining in importance as utilities turn to cleaner, cheaper alternatives. Coal’s share of power generation will fall below 40 percent this year for the first time since the government began collecting data in 1949.

GAS RISING: Utilities are switching to natural gas because it is has plummeted in price and doesn’t run afoul of tighter environmental rules.