IN 1516, Mark Anthony Zimara hit upon the ultimate idea in renewable energy. Instead of merely using windmills to generate energy, he suggested employing them to power bellows to blow air… back at the windmills! The self-blowing windmill, he thought, would run forever.
Zimara’s machine failed, of course. The laws of thermodynamics put the kibosh on perpetual motion machines. No matter how cleverly designed, they will eventually grind to a halt without ever producing the desired free work.
This is due to an all-pervasive macroscopic temporal asymmetry: entropy, a measure inversely related to the energy available for work,…
