A fascinating talk by J. David Hughes, a research fellow at the Post Carbon Institute, given at Cornell-5-2-12, "Energy Sustainability Dilemma : Powering the Future in a Finite World". Most of the easy energy is gone. This was from oil which was plentiful, and easy to get, with a very high net Energy Return on Investment (EROI). Now we are pursuing Deep Ocean Drilling, Tar Sands, Fracked Shale Gas, etc.
Are we heading for a dead end? What about Wind and Solar? Can they make up the difference? This talk is somewhat technical, but essential if we are to understand our energy options as our society pushes for more energy.