How Everyday Behaviors Can Produce Clean Energy

How to generate energy from sidewalks, roads, railways — and every breath you take.

All Vibrations are good vibrations in the world of energy harvesting. Whether it's a road under heavy traffic or commuters pounding the sidewalk pavement, micromovements on any surface can be converted into clean energy by power-scavenging devices fitted with piezoelectric (PE) crystals. These pressure-sensitive materials — normally made of ceramics — give off a small charge when "squeezed, squashed, bent, or slapped," explains Markys Cain, a materials scientist at the British National Physical Laboratory. ("Piezo," by the way, is derived from the Greek for "press" or "squeeze.") So a PE layer slotted beneath a supermarket parking lot could, for example, use the movement of customers' cars to power checkout conveyor belts or pump that free electricity back into the grid. Here's how these sparky substances will be turning vibrations into volts.

ROADS

Late last year, Haifa-based Innowattech dug up 33 feet of Israel's Highway 4 and inserted PE generators 2 inches below the blacktop. If the gizmos were placed under one lane of a busy half-mile stretch (at an estimated cost of $500,000), the company says the generators could create enough energy to meet the needs of 250 homes.

 

SIDEWALKS

There's nothing pedestrian about Pavegen Systems' walkway slabs, which generate a steady 2.1 watt hours when positioned in heavy footfall zones. This summer, clusters of energy-absorbing pads will be installed at a major London transport hub to power lighting and signs.

 

RAILWAYS

Railway tracks absorb huge amounts of kinetic energy from passing locomotives. Innowattech taps that train strain with customized concrete sleepers loaded with PE generators. The firm is currently testing the kit with Israel Railways and estimates the passage of 300 cars an hour over 1 kilometer of track will provide enough juice for 150 households.

 

SPORTS STADIUMS

High-energy fan celebrations in the bleachers could soon be charging LED displays and other devices around ballparks. Powerleap, based in Ann Arbor, Michigan, aims to start testing PE floor tiles (a square foot will cost between $50 and $100) in stadiums around the world next year.

 

HELICOPTERS

The U.S. military uses battery-powered wireless sensors to check chopper rotors and other parts for damage. Vermont-based MicroStrain has created sensors that suck energy from the very vibrations and strains they're designed to monitor.

 

 

HUMAN BODIES

The rise and fall of your lungs during breathing produces close to 1 watt a minute. Up to 80% of that energy can be captured with nano-size crystals printed onto flexible film developed by Princeton scientists. The biocompatible generators could soon be implanted to recharge pacemaker batteries.

Illustrations by MCKIBILLO

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4 Comments

  • Steve Offutt

    Theunis - You've mixed up your watts and watt-hours. Watts is a measure of rate (like speed); watt-hours is an amount (like distance). (Be sure to chew out your editor, too; that's the sort of thing they are paid to catch.)

    So "generate a steady 2.1 watt hours" is nonsensical, like "generate a steady 2.1 miles." What you probably meant is "a steady 2.1 watts."

    And the same problem with "breathing produces close to 1 watt a minute," which would be like saying "going 30 mph a minute," which makes no sense. What you probably meant is "breathing produces close to 1 watt." Which, in the end, is not much. At that rate, it would take 42 days to generate 1 kWh (1000 watt-hours) of electricity, which costs about 8 cents where I live. But perhaps that is enough to recharge those batteries.

  • Farokh Monajem

    The key is to extract any available energy. The jury is out as to the effect on these technologies on cars. Is the extra energy they might expend on driving on these surfaces more than compensated for by the energy we gather?

    Does the same logic apply to sidewalks? Will we required more energy to walk generating electricity?

    There are other areas where energy is also released, for instance escalators which have not been taped yet.

    I live in Toronto. We have light rail as one of our public transportation venues. They have steel ties buried under concrete. I wonder if the same rules regarding railway ties can be used here as well?

    And then there is this energy source prototype: http://www.gizmag.com/kaist-pr...

    So much hope!

  • Cassie Renee Fitzwatrer

    That is the coolest thing I have read in a long time! I have often wondered about the ways to lower energy costs as well as depleating our resources. This takes care of both!

  • Bradley Norris

    Just as it is difficult to walk efficiently on a soft surface (such as mud) that absorbs some of the energy of walking, I am concerned that cars that drive on a road that absorbs energy will expend more energy driving over it. The key is to extract waste energy, not any available energy.