Jim Robo, Who Built NextEra Into Clean-Energy Giant, to Exit (2)

Jim Robo, who transformed NextEra Energy Inc. from a sleepy Florida utility into a clean-energy juggernaut, is stepping down as the company’s top executive.

NextEra appointed company veteran John Ketchum as successor, naming him president and chief executive officer as part of a series of management changes announcedTuesday that take effect March 1. Robo, who’s also chairman, will become executive chairman for a brief period, and Ketchum, 51, is expected to be appointed to NextEra’s board. Shares plunged.

NextEra’s Jim Robo named executive chairman.

Photographer: Gonzalo Marroquin/Patrick McMullan/Getty Images

Robo, 59, has been instrumental in building NextEra into the biggest U.S. wind and solar company. At one point ...