A Netherlands train station is using a revolving door to produce some of the building’s electricity. The train station anticipates the coming and going of patrons to provide 4,600 kWh of energy per year.
The revolving door uses a generator to harvest the kinetic energy produced when the door spins, and a supercapacitor stores the energy. The energy is used to power the train station cafe's LEDs. When the stored energy from the door is used up, the station's main energy supply kicks in. The station also displays the amount of energy generated as customers walk in and out.
Kinetic energy generators could go a long way toward energy generation if they're consistently implemented in new buildings and renovation projects.