The Energy of Crowds

Fascinating piece in the WSJ today about the rise of parasitic power generators: technologies that capture electrical energy that is otherwise a wasted byproduct of everyday human activities, such as walking or exercising. While this has long happened with bike lights, and is emerging in gyms, other examples are legion:

Enviu, a Dutch environmental group, is building a
nightclub in Rotterdam that will have a dance floor that converts
vibrations from all those feet into electricity. One potential design
for the floor involves piezoelectric crystals, which generate a small
electric current when compressed. But Enviu’s 20-by-20-foot floor cost
$260,000 and will generate only enough power to run some lights
embedded in it.

A London design firm called Facility:Innovate has been
developing flooring materials that could ultimately be used to collect
energy from throngs of people walking into busy subway tunnels. In one
design, each step on the floor would push fluid through a microturbine,
generating electricity.

Human power may have more practical uses as an energy
source in developing countries or in remote environments where
electricity isn’t available. The U.S. military has spent millions of
dollars in recent years on research into so-called “heel strike
generators” that can be placed in soldiers’ boots and might help reduce
the battery load they have to carry.

Larry Rome, a biology professor at the University of
Pennsylvania, recently launched a company called Lightning Packs that
aims to sell backpacks that generate electricity from the jiggling
motion of walking. In a recent test, his prototype was able to produce
about 15 watts of power from the up-and-down motion of the pack.


  1. I’ve always wondered why gyms haven’t found a way to eliminate their electricity bill. It’s literally like free slave labor at their disposal and yet they capture none of the energy.

  2. Lloyd Alter says:

    There is no such thing as free energy. Essentially each of these devices is converting calories that you eat to energy that they take without compensating you, but you are doing extra work. Fortunately most of us have excess calories to burn but it is a very expensive and silly way to convert our lunch into energy.

  3. Prison! That’s a recent dream of mine: instead of busting rocks or lifting weights or playing basketball, inmates are forced to log hours per day on stationary bikes or treadmills generating electricity to be fed back to the grid (or to power the prison) – they could literally be like hamster wheel-powered facilities! How great!

  4. Would it be great if there is a device that could covert my old home treadmill and stationary bike to generating electricity that I could sell back to the utility company.
    Oh wait, I do have a device I made from the 70’s during the last energy crisis.

  5. Hmmm, anyone see the movie “The Matrix”? Human beings were used as a source of power. Talk about parasitic!

  6. Peter Clark says:

    This reminds me of Lance Armstrong’s ESPN commercial from a few years back – the ultimate in human-generated energy:

  7. I like the prison idea – great way to turn crooks into walking/running bursts of energy. Cool.