The book https://en.wikipedia.org/wiki/The_Windup_Girl https://en.wikipedia.org/wiki/The_Windup_Girl was partially about the idea of a post oil world. I remembe

The book https://en.wikipedia.org/wiki/The_Windup_Girl https://en.wikipedia.org/wiki/The_Windup_Girl was partially about the idea of a post oil world. I remember there being mastodons they were using to wind springs and guns that had no explosive charge but instead had kinetic stored energy. Kind of like the energy slave idea.