KKR, the big private equity firm, and the Environmental Defense Fund, the big environmental group, have been working together for about a year to look for ways to make KKR’s owned companies more sustainable. Guess what? The KKR-owned firms have saved about $16 million doing so (and they got “free” consulting to boot). I wrote about this the other day. Here’s an interview I did with Gwen Ruta, the vice president for corporate Partnerships at EDF.