The Federal Energy Regulatory Commission has endorsed many of Duke's proposals for its new license. But the utility disagreed with nearly three-dozen of the agency's recommendations in a draft environmental study, The Charlotte Observer reported.
The final decision on the license is expected next year.
The environmental recommendations could be changed or removed before then, said FERC spokeswoman Celeste Miller.
The key sticking point is federal regulators calling for Duke to buy back undeveloped portions of land along the 225-mile shoreline of the Catawba River and enforce a 50-foot buffer along the waterway in North and South Carolina.
Duke officials said that would be too expensive, citing a study by the utility that found buying 100-foot-wide swaths along 800 miles of undeveloped shoreline would cost more than $2 billion.
The shoreline protection proposals are similar to recommendations from the U.S. Fish and Wildlife Service, which has frequently criticized Duke for the level of development along its 11 reservoirs, especially those in the Charlotte area.
"Acquiring remnants of land in key locations and consolidating longer expanses of shoreline would not be terribly expensive if done over time, and done in conjunction with other programs," said Fish and Wildlife Service biologist Mark Cantrell.
Duke said other recommendations by federal regulators would keep the utility from fulfilling some of its promises in a 2006 agreement, including access areas and land deals for local governments.
"We signed the agreement with the understanding that it provided us some certainty and predictability," said Mark Oakley, Duke's licensing manager. "We feel like protecting our benefits and burdens is the best way to protect everybody else."