Duke had obtained construction and operating licenses (COL) to build two AP1000 units, one at the North Carolina site and the other at the Florida site. The construction of that technology, however, is under a dark cloud after cost overruns at the Vogtle nuclear plant in Georgia and the V.C. Summer plant in South Carolina helped cause the bankruptcy of Westinghouse Electric Co., which took over the under-construction projects from CB&I in 2015.

"This settlement allows us to move forward to create a smarter energy future for our customers and communities," said Harry Sideris, Duke Energy state president, Florida, in a statement. "It resolves the future of the Levy Nuclear Project and reinforces our commitment to building cost-effective solar in Florida. It also makes smart investments that will offer customers more information, choices and control of their energy needs while also providing greater reliability."

As part of an agreement with Florida regulators and consumer groups, Duke's Florida subsidiary will invest almost $6 billion over four years in grid modernization, 700 MW of solar, smart meters and electric-vehicle stations.

The agreement calls for Duke to absorb the remaining $150 million in remaining costs for the Levy Nuclear Project. Customers already have paid $800 million for preliminary planning and regulatory work on the plant, originally proposed by Duke's predecessor, Progress Energy. In 2009, Progress entered into an engineering, procurement and construction agreement with The Shaw Group to build the plant on a greenfield site in Levy County, Fla. Construction never started. In 2013, Duke, which by then had taken over Progress, canceled construction plans, though it did secure a COL from the Nuclear Regulatory Commission in October 2016.

The company says it will begin construction on its sixth Florida solar plant, in Hamilton County, early in 2018. The project will have 300,000 solar panels and produce 75 MW of solar energy.

In North Carolina, Duke received in December 2016 a COL for its proposed Lee nuclear generating station. It has asked regulators to recover the $541 million it spent on regulatory work for the plant. If approved, Duke's costs in North Carolina, including coal-ash management and power-plant improvements, would result in a 16.7% increase in monthly residential bills. NC Warn, an environmental and consumer group, has pledged to fight the rate increase.