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Will a speed bump power the grid?

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American



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The Burger King on U.S. Highway 22 in Hillside, N.J., looks no different from any other franchise in the state. Customers pull in and out all day, and at least 100,000 cars visit the drive-thru each year. And now a newly installed, mechanized speed bump (video) will both help them slow down and harvest some of that coasting energy.

"We use the weight of a car to throw a lever," explains Gerard Lynch, the engineer behind the MotionPower system developed for New Energy Technologies, a Maryland-based company. "The instantaneous power is 2,000 watts at five miles-per-hour, but it's instantaneous [which means some form of storage will be required.] The real key is how do I get a million cars to do that for me."

This demonstration project won't actually provide electricity to either the Burger King or the grid, but it will employ a mini-flywheel—a mechanical device that stores energy by spinning—to test storage potential. A higher price can be charged for electricity that is fed into the grid at the right moment. "How do we capture and hold these pulses efficiently so we can dispatch them at the right time when the electricity rate is most advantageous," Lynch says. "Here in Hillside, the average price when you take delivery is 17.5 cents per kilowatt-hour. It's double that in peak summer. The idea is: let's hit it all day and return [that power] at 3 PM in the afternoon."

In the future, New Energy may employ flywheels, super-capacitors or some other form of storage, but this demonstration is intended just to prove that the speed bump won't fold under continuous pressure from the 1,000 pounds per wheel of weight from an average car—and that people accept it. "Do people say, 'Get it out of my way,' or 'This is pretty cool'?" Lynch says.

Assuming that the latter is the case, the company hopes to develop the next generation of the technology, which could be employed anywhere from the local fast food joint to rumble strips at toll plazas. After all, there are some 251 million registered vehicles on U.S. roadways, so harvesting some of the energy otherwise lost in coming to a stop might make sense for use in powering streetlights or even the grid. "Our new device will look completely different, more like a traditional speed bump," says Meetesh Patel, New Energy's CEO. "The first guy that went over it didn't even realize that he had created electricity in his drive to get a burger."

Image: Courtesy of New Energy Technologies