The Institute for Local Self Reliance based in Minneapolis, USA has just produced an interesting map of the United States suggesting that 31 of the 50 states can be self sufficient for electricity if using only in state, renewable resources. Only 5 states were at 30% or less. The map makes an interesting point- while not likely, or in some occasions the best, overall economic solution, it is feasible for most US States to be able to adhere to more modest renewable energy portfolio requirements. If technology continues to improve the economics in the future, this percent of renewable requirements could increase to satisfy energy loads.
Non-Americans may find this interesting as the geography of the US is almost as varied as that of the world. The map also suggests that some areas are renewable resource poor, and will need alternative plans if they intend to clean up generation. See the link to read about the study and its assumptions.