The Environmental Defense Fund has struck a first-of-its-kind “green portfolio” deal with gigantic private equity firm Kohlberg Kravis Roberts. The partnership plans to develop tools to measure and improve the environmental performance of KKR’S U.S. companies, with metrics including energy efficiency, greenhouse-gas emissions, water consumption, and toxic waste. KKR has more than $185 billion in revenue and owns 46 companies, including Toys “R” Us, U.S. Food Service, Sealy, Nielsen, and Energy Holdings (formerly TXU); EDF and KKR were involved in brokering a 2007 buyout of TXU that resulted in coal plants being canceled, and the transaction spurred partnership talks between KKR and EDF. Who ever said good can’t come from coal?