For those of you who might be interested in the interaction between
the economy and energy there is a group of videos at an energy forum
in Ireland.
The video by Reynolds is the economists view of what happened in
history with the British Empire and the fall of the communist system.
It continues into the present day.
The talk by Colin Campbell will give you a good insight.

http://www.localcampus.com/

I have not seen the other videos.