A new project at National Physical Laboratory in the UK aims to develop a much more efficient piezoelectric energy harvester. They found a serious glitch in current piezo devices that keeps them from giving their best at converting mechanical stress to electricity.
Despite the fact that the powers outputted by piezoelectric devices are small (per individual unit), they can be assembled in hundreds or even thousands to produce significant amounts of power from shocks coming from highways or railroads.
Today’s piezoelectric devices are typically made of a vibrating cantilever covered with a piezoelectric layer over their entire surface. However, the scientists discovered that covering the entire surface with the piezoelectric material is reducing the system’s overall conversion efficiency. They proved that up to 25 percent of the unit’s potential output is lost this way.
Their conclusion was that the most efficient scheme for a piezoelectric device is to cover the cantilever for only two thirds with piezoelectric material.
Israel and several states in the U.S. have already covered areas of highways with piezoelectric materials which convert the power of passing cars into electricity to power lights and billboards. These devices are especially useful in areas where braking is used a lot.
NPL’s Markys Cain says that there’s also a huge marketing potential, as the energy harvesting market will reach $4.4 billion by 2020, from only $605 million in 2010, so anyone having a little piece of that pie will likely be successful.