Blackstone and NRG acquire Dynegy assets; Constellation grabs Boston Generating; Exelon gets Deere Renewables; plus details on nearly $7 billion in bond offerings during the month of August, including: a two-tranche, $2 billion issue by Chesapeake; NRG’s $1.1 billion flotation; and major issues from Sempra, Edison International, FPL, Detroit Edison, Dominion and others.