The two coal-powered and three biomass-based plants -- with a total generation capacity of 70 megawatts (MW) -- came into Exelon’s fold following the completion of the Constellation deal in March.
Tokyo-based IHI acquired Exelon’s 50 percent stake in four power plants and 45 percent stake in one plant.
Financial terms of the deal were not undisclosed.
Power companies have announced plans to shut or sell coal-fired power plants due to the proposed stringent federal environmental regulations, weak power market and record switching from coal to natural gas-fired generators.
Tuesday’s sale comes less than two weeks after Exelon sold four coal-powered plants to Raven Power Holdings for $400 million to fulfill the conditions for its merger with Constellation.
Exelon’s shares were slightly down at $37.58 during late morning trade on the New York Stock Exchange.
Reporting by Thyagaraju Adinarayan; Editing by Sriraj Kalluvila