The Ultimate Way To Power A Big City
A few years ago I attended a conference in New York. During that conference, we experienced a major electrical blackout. Many of the conference attendees had to sleep on the ground in Times Square. Now, in the UK, engineers are working on a way to convert the vibrations from foot, train, and automobile traffic into energy.
Powering Up, One Step at a Time
British engineers are converting street vibrations into electricity and predict a working prototype by Christmas capable of powering facility lights in the busiest areas of a city.
"We can harvest between 5 to 7 watts of energy per footstep that is currently being wasted into the ground," says Claire Price, director of The Facility Architects, the British firm heading up the Pacesetters Project. "And a passing train can generate very useful energy to run signaling or to power lights."
Like solar and wind proponents, vibration harvesters argue that abundant, clean energy is all around us and goes to waste. The challenge is how to store the power efficiently so it provides a continual output even if the vibrations from footsteps or passing trains temporarily taper off.
Price has charged Jim Gilbert, an engineering lecturer at the University of Hull, with developing the prototype system for capturing footfall. Gilbert is working with hydraulic-powered heel-strike generators, which he believes could be installed in the floors of busy public places like subway stations. Those stations typically capture the footfall of 20,000 commuters an hour during peak usage -- multiplied by 5 to 7 watts a person, that's more than enough to power a building's lights for the day.
"A few years ago I was asked to develop heel-strike generators for military applications -- generators inside boots to power cell phones so soldiers wouldn't have to carry around heavy rechargeable batteries -- but it was very difficult to ensure that the generators inside the boots didn't get dirty or wet," says Gilbert.
Inside the floor, far from the elements, Gilbert thinks the generators will be safer, but they still need to be robust and reliable to withstand the tromping of tens of thousands of people.
Price is working with Tony Bates, a business development manager for the Scott Wilson engineering firm, on a prototype to harvest vehicle vibrations.
That arm of the project is to develop wireless, piezoelectric micro generators that resonate at the frequency of passing trains and other vehicles and can be attached to outdoor light fittings. (A similar technique was used in Nike and Apple Computer's recent collaboration on Nike+ shoes that record and sync a runner's pace and distance with an iPod.)
The prototypes are scheduled for assembly by December 2006. Then, Price says, the Pacesetters Project participants will do some "robustness testing in the field" and consider production deals with Asia to get the costs down.
"It will allow lights and power to be created where previously it was too expensive or difficult to dig up the transport infrastructure to wire them into the main grid supply," says Price. "(This could) potentially save billions of pounds in building works."