Piezoelectric energy--energy produced when stress is applied to an object--is already used to produce power for roads, subways, and nightclubs. Now a Sainsbury supermarket in Gloucester, England, is using kinetic plates to keep checkout lines moving.
Sainsbury's road plates, which are similar to those seen on London streets, produce 30kWh of energy every hour from cars passing over the bumps in the store parking lot. The Highway Energy Systems-designed road plates are pushed down by the weight of the vehicles, creating a rocking motion that turns generators. Energy from the generators is captured and used inside the supermarket.
The system, which generates more than enough energy to power the store's checkout lines, supposedly doesn't affect vehicle fuel efficiency. That's a sore spot for existing piezoelectric projects, as detractors claim that they are "energy thieves" that suck up energy from gasoline and convert it into forward motion. But if the Sainsbury road plates are in an area where cars are slowing down anyway (i.e. a downward ramp), then the energy is clean.
Piezoelectric road plates are just one of Sainsbury's sustainable initiatives. The Gloucester Quays store also uses rainwater to flush toilets and solar thermal panels to heat 100% of the water used during the summer.
[Via UK Guardian]