The World After Abundance 
By John Michael Greer 

http://www.countercurrents.org/greer280510.htm

In the energy crisis of the Seventies, relatively simple conservation and efficiency measures, combined with lifestyle changes, sent world petroleum consumption down by 15% in a single decade and caused comparable drops in other energy sources across the industrial world. Most of these measures went out the window in the final binge of the age of cheap oil that followed, so there’s plenty of low hanging fruit to pluck