A new method of generating power, no need fossil fuel, coal, sunlight, wind water; what they need is only the people to step on them. In year 2006, a test is carried out at two of the Japan train station, Tokyo station and Shibuya station.
Initial test can only produce 0.1W per second when the tile is step by a person of about 60kg of weight, and the generation is improved to 1W per second one year later.
Piezoelectric basically can describe as an applied mechanical stress to generate a voltage and an applied voltage will change the shape of the solid by a small amount (up to 4% change in volume). In physics, the Piezoelectric effect can be described as the link between electrostatics and mechanics. A very common daily life application of Piezoelectric concept is our car's air bag sensor. The material detects the intensity of the shock during accident, then sends an electrical signal which will triggers the airbag.
Only non conductive material can be used for Piezoelectric effect, Piezoelectric materials can be divided in 2 groups; crystals and Ceramics. The most well-known piezoelectric material is Quartz(SiO2).
This method should be another good option of renewable energy!!