In one of those "surely someone has thought of it before" moments, a giant railway company in Tokyo has started testing a system that harvests electricity generated by the movement of passengers through its ticket gates.

JR East has developed a piezoelectric system with Keio University and is currently trialing it on a small scale in its own offices in Shibuya. The idea is to utilise the kinetic energy of the millions of commuters passing through Tokyo area stations to provide extra power where it's needed.