The latest invention to spring from the fertile mind of man is a device that generates electricity from passing traffic. New Energy Innovations has developed a product called the Traffic Powered Renewable Energy System (TPRES).
TPRES uses a series of air pumps embedded in the road. Each time a car passes over, the pumps force air through a series of tubes, driving an air motor/turbine to produce electricity, which can be locally stored or fed to the grid.
The company claims that one intersection, with heavy traffic, can power 40 homes for a year. Out of curiosity, how many EVs could be charged with that amount of power? Some quick math, based on average US usage of about 30 kWh a day per house (per the EIA) indicates that this gadget could pump out about 1,200 kWh a day – enough to fully charge 50 LEAFs.
Adherents of the laws of thermodynamics will point out that the concept amounts to simply stealing a little energy from each passing driver (and some will smile at the idea of that oil-generated energy being used to charge EVs). However, as one commenter at Green Car Congress argues, at locations where cars are always braking, such as off-ramps, stop signs or toll booths, some of the energy normally lost to heat by friction brakes could be recovered.