Harvesting the world’s (wasted) mechanical energy
With one stomp of his foot, Zhong Lin Wang illuminates a thousand LED bulbs – with no batteries or power cord. The current comes from essentially the same source as that tiny spark that jumps from a fingertip to a doorknob when you walk across carpet on a cold, dry day.
-Georgia Tech News Center (John Toon)
Dr.Zhong Lin, the Chair in Materials Science and Engineering & director of the Center for Nanostructure Characterization, has leveraged the enormous surface area enabled by nanostructures & the triboelectric effect to generate incredible quantities of electricity.
Since their first publication on the research, Wang and his research team have increased the power output density of their triboelectric generator by a factor of 100,000 – reporting that a square meter of single-layer material can now produce as much as 300 watts
-Georgia Tech News Center (John Toon)
As with many great discoveries, this began as an accident. Wang & his team were investigating another form of energy harvesting, the piezoelectric effect, when an incorrectly assembled piezoelectric generator allowed two surfaces to rub together. When this generator produced far more energy than expected, the team traced the anomaly to the triboelectric effect.
I remember seeing the triboelectric effect in my electronics class, we’d touch a Van De Graaff generator, our hair would stand up, and then we’d attempt to recreate Michelangelo’s The Creation of Adam – whereupon a bright spark of plasma would form between our fingers, and a prick of pain right at the tips.
This process – electrostatic induction, followed by electrostatic discharge – would generate up to 8 amps and 12,000 volts, which sounds like enough to be dangerous, but isn’t; volts and amps tell only part of the story.
Another metric, the Joule, is far more useful. It encodes the total power available to do work – here the total energy available for static discharge. Another unit, the Watt, encodes the work done per second. The aforementioned static discharge totals 0.0072 Joules. Given a minimum hazardous stored energy of 10 Joules, I see how my classmates weren’t dying.
Back in fall 2011, Dr.Zhong Lin and his team were generating electricity on roughly that order of magnitude. In order to generate more energy they needed more surface area, which they have achieved with tiny structures on the surface of sheets – this increases the available surface area much like the gyri and sulci do for the Cerebral Cortex in the Human Brain. Because of this, a square meter of Dr.Zhong Lin’s single-layered material can produce nearly 300 watts!
In Dr.Zhong Lin’s words:
Mechanical energy is everywhere, independent of weather, independent of day and night, independent of season – so anything you can think of – smaller scale from finger tapping, from your touchpad, from walking, to car motion, even train motion, we can do that. We harvest energy [that] we have been wasting for years. We never use[d] that [energy]. So I anticipate [that] this can not only contribute to power sources for portable electronics, but also can contribute power sources for large scope energy needs. We can contribute significantly to the worldwide energy need in the near future, and we even think for – for big ocean waves, theoretically we save 31 terawatts energy can be harvested – that’s twice of today’s world energy consumption. It will not take too long, 5 years.
-Harvesting the World’s Mechanical Energy (youtube video)
This technology has the potential to change the world.
via phys.org (Capturing wasted electricity with triboelectric generators) & Georgia Tech (Harvesting Electricity: Triboelectric Generators Capture Wasted Power)