What is the concept of piezoelectricity?
It is the electrical energy produced from mechanical pressure. A negative charge is produced om the expanded side of the pressure and a positive charge on the compressed side. Once the pressure is relieved, electrical current flows across the material layer and can be distributed to an electrical network.
Application of this concept in construction
Piezoelectric sensors could be implemented in floors to capture the electrical charge created by the pressure of footsteps from people walking on it. Crystal or ceramic materials conversion of pressure to electrical charge then represent a new type of energy source.
It could be used for lights on dance floors for example but why not pushing this technology further in crowded areas such as malls or sidewalks. For instance, piezoelectric dance floors with LED lights can produce 60% of the total energy required to operate a club. Another example is that 28,500 footsteps can generate energy to power a train for one second.
Link for an example of piezoelectric dance floors: http://www.youtube.com/watch?v=NNBOfUwRLgw
One limit of this technology is that the power generated is high in voltage but low in amperage. So this installation has to be completed with a voltage regulator in order the energy to be stored for a long-term use.
Furthermore, we can wonder if the cost of such kind of technology is justified by the small amount of power produced.