Global investment firm The Carlyle Group has agreed to sell Cogentrix Energy, the owner of more than a dozen U.S. power plants, to private equity group Quantum Capital for $3 billion, the Financial Times reports. Carlyle bought the North American power generation assets held by Cogentrix Energy from Goldman Sachs Group back in 2012. Earlier this year, FT reported that Carlyle had hired investment bank Lazard and law firm Latham & Watkins to advise the group on a potential sale of Cogentrix. A transaction could value the power group at up to…