The Houston company says the deal will boost its presence in the Midwest and New England. Dynegy produces power that it sells through wholesale markets.
The company plans to spend $2.8 billion for Duke's assets and $3.45 billion for those of Energy Capital Partners, or ECP. It says the deal will add about 12,500 megawatts of coal and gas generation. Dynegy also expects the acquisitions to complement its existing business and add fuel diversification.
Dynegy Inc. says both deals should close by the end of next year's first quarter.
Shares of Dynegy are climbing in premarket trading.