Piezoelectricity is the charge that is generated in certain materials, mostly crystals, when they experience mechanical strain. This technology is already being used in a variety of common tools such as cigarette lighters and push-ignition barbecue grills. Piezoelectricity has the potential to provide us with a great source of green energy if it is properly utilized. As with many other renewable energy sources, scientists are diligently working to find the best possible ways to harvest piezoelectric energy.
Researchers at Cornell University have designed a vibrational wind turbine that can operate silently on rooftops. A variation on this idea is the Piezo-tree, a structure in which a piezo stem is covered with synthetic leaves. As the leaves flap in a breeze, they generate electricity, which can then be used by homes and businesses. Several models of the Piezo-tree have been tested successfully and scientists are currently working toward finding the best design and materials to optimize energy output.
The Innowattech Company is looking toward another source of movement for their piezoelectric design. They propose placing piezoelectric materials underneath busy roadways so the vibrations of passing cars can be put to use in generating electricity. This method, called parasitic energy harvesting, is currently being tested on a small scale but designers state that a typical 4-lane highway could produce just over 2 megawatts of power for every mile of roadway. This system could also potentially be used to harvest energy from airport runways and rail systems. In fact, the Tokyo subway system currently has approximately 270 square feet of piezoelectric flooring in place. With millions of travelers walking through the station each day, the flooring produces around 1400 kilowatts of electricity per second, enough to power the system's ticket gates as well as electric lights and displays.
On a smaller and more personal scale, scientists at the University of Michigan have developed a piezoelectric generator that measures less than Â½ inch across. This tiny powerhouse can be used to power wristwatches, pacemakers, and health sensors using only the movement and vibrations of the human body. It is especially useful since it creates energy from any random movement as opposed to the regular, rhythmic motion required by some piezoelectric generators. Another useful creation is the piezoelectric cloth designed by scientists at Bolton University in the United Kingdom. This cloth can be made into clothing, which will then provide power for cell phones and other small personal electronics.
Our world is in a constant state of motion. Plants and trees swaying in the wind, vehicles moving, people playing and living their daily lives. Why not capture all that motion and turn it into a clean, endless energy source? Piezoelectricity is a technology that has limitless possibilities and we are sure to see new and larger scale inventions that will harness the power of motion for our use.