The Center for American Progress has an interactive map up, showing per-capita CO2 emissions from U.S. states. No big shock — the big emitters are the big coal users, and the low emitters are the big hydro users.
The point CAP is pushing is this: “The 10 cleanest states based on per capita emissions … have aggressive renewable energy and/or efficiency programs.”
I think this probably gets the causation backward. The states with the least coal in their electricity mix, and thus the lowest per-capita emissions, are more likely to get behind R&E programs. States with lots of coal, where R&E would mean serious economic disruption, are less likely to implement such programs.