The CEO of US green power giant NextEra delivered a downbeat verdict on offshore wind, citing its costs and major operational challenges compared to onshore renewables.

John Ketchum told the CERAWeek energy event in Houston that offshore wind is “very capital intensive” and subject to a string of additional complexities not faced by other generation sources.

"We find it hard enough just to take care of a fleet onshore with some of the issues that we deal with as a company, and we're best in class," Ketchum told CERAWeek, Reuters reported.