Good Clean Tech is of the best kind. And while it isn't cheap to install it eventually pays for iteself and them some. imagine if every Marquette, Bucks, and Bradley Event had revoloving doors hooked up to power the place. Now think about the rest of the city? Cool, huh?

You probably come across revolving doors almost on a daily basis, but I bet this is the first one you've ever heard of that can actually harness kinetic energy. In the Natuurcafé La Port coffee shop in Netherlands, a special revolving door was built that could harness the kinetic energy generated by the people passing through it. The door is equipped with an energy generator that produces the power stored in a set of supercapacitators. People passing through could clearly see the mechanism through the transparent glass on the ceiling.

Energy generated admittedly isn't anything jaw-dropping but still total to around 4600 kWh per year. Most of that is used to power the LED light at the top of the structure for illumination as well as to control the door's revolving speed to avoid accidents. There's a visible light scale at the inside to indicate energy harnessed - red or orange for low energy from slow entries through the doors and green for high energy harnessed brought about by fast-paced entries. The energy-harnessing revolving door is part of a refurbishment process of the railway station where the café is located...