The U.S. utility sector is undergoing rapid consolidation as consumption in many parts of the country flattens while consumers, companies and governments look for ways to be more energy efficient.

Juno Beach, Florida-based NextEra said it would also buy Southern Co's interests in the Oleander and Stanton natural-gas plants.

Including debt, the deal is valued at $6.48 billion, NextEra said.

Gulf Power, which serves around 450,000 customers in eight counties throughout northwest Florida, has roughly 9,500 miles of power lines and 2,300 megawatts of electric generating capacity.

Florida City Gas, which serves approximately 110,000 residential and commercial natural-gas customers, has 3,700 miles of natural gas pipelines.

NextEra, which expects the deal to add to its earnings immediately, said it intends to finance the transaction through the issuance of new debt.

Southern Co plans to use the transaction proceeds to reduce its debt.

BofA Merrill Lynch and Goldman Sachs & Co served as financial advisers to NextEra, while Citigroup Global Markets Inc advised Southern Co.

(Reporting by Laharee Chatterjee in Bengaluru; Editing by Maju Samuel)