By David French

NEW YORK, Oct 6 (Reuters)NextEra Energy Inc NEE.N Chief Executive James Robo joked last week he does not pursue small acquisitions because the reward is not worth the “brain damage” of getting them past regulators.

Yet his $65 billion-plus pursuit of Duke Energy Corp DUK.N will only pay off if he can overcome major regulatory hurdles in putting together the biggest ever U.S. utility deal, industry experts said.

Duke rebuffed a takeover approach from NextEra, the world’s largest producer of renewable energy from wind and sun, as inadequate, Reuters reported last Wednesday. The deal would help accelerate Duke’s transition away from coal- and gas-fired power plants.

NextEra, already the largest U.S. utility with a home base in Florida, would need approval from regulators in all six states where Duke operates: Florida, Indiana, Kentucky, North Carolina, Ohio and South Carolina. The Federal Energy Regulatory Commission would also need to assent, and the Department of Justice has authority to review the deal for potential antitrust issues.

“This kind of deal would raise significant regulatory considerations,” said Jane Rueger, a partner at law firm Perkins Coie.

Florida would be the area of most regulatory concern, according to industry experts. Of the 8.1 million customers served by privately owned electric utilities in 2019, 7.3 million got their power from Duke or NextEra units Florida Power & Light and Gulf Power, according to the Florida Public Service Commission.

Utilities typically pledge to sell assets or build extra transmission lines to assuage anti-monopoly concerns. Duke Energy made such concessions to regulators in the Carolinas and Florida when it bought Progress Energy for $13.7 billion in 2012.

NextEra, however, would have to give up significant business in Florida and risk upsetting its relationship with regulators ahead of negotiations on new caps