# Harvesting Human Movement Energy **URL:** \ **Category:** Factual Questions\ **Created:** [November 24, 2017, 6:27pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610 "2017-11-24T18:27:35Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![babarello47](https://avatars.discourse-cdn.com/v4/letter/b/22d042/32.png) [@babarello47](https://boards.straightdope.com/u/babarello47)\ **Post date:** [November 24, 2017, 6:27pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/1 "2017-11-24T18:27:35Z")
I’ve been wondering recently about the power of human movement to generate, well, power. We do so many movements, from turning around or shaking hands to walking to standing up or sitting down, etc. – not to mention aerobic exercise. Has anyone ever tried to tap that movement as an energy source? I would imagine that it would be possible to do it in a way that doesn’t involve massive amounts of wires and electrodes that would be annoying and inconvenient. Does anyone have any insight or info on this? ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [November 24, 2017, 6:40pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/2 "2017-11-24T18:40:20Z")
The problem is if you want to harvest the energy, you have to apply force to something. Just as an example, if you shake hands with someone, both hands would have to be attached to a rope/strap/whatever that turns a generator in order to use that energy. A treadmill, stationary bike or stairclimber could similarly be used to generate electricity. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [November 24, 2017, 6:41pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/3 "2017-11-24T18:41:45Z")
Of course people have been tapping into it. Automatic watches are/were probably the most common example. Not yet (AFAIK) enough power for a smartphone, if that’s what you need, at least not without [special accessories](http://vancouversun.com/news/staff-blogs/knee-mounted-device-generates-electricity-while-you-walk). ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [November 24, 2017, 6:45pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/4 "2017-11-24T18:45:51Z")
Welcome to SDMB. What a great first post! Here’s an interesting summary of the current state of the technology: [Wearable Biomechanical Energy Harvesting Technologies](http://www.mdpi.com/1996-1073/10/10/1483/pdf). (links to PDF for downloading) It seems most interest in this sort of gear is for making one able to power one’s own electronic devices. And my cursory reading of the paper makes me think the tech isn’t quite there yet, but isn’t that far away. The tech has gotten more sophisticated than I recall, in the days of my first self-winding watch, back in the 1960’s. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 24, 2017, 6:46pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/5 "2017-11-24T18:46:13Z")
> [@babarello47](#): > > I’ve been wondering recently about the power of human movement to generate, well, power. We do so many movements, from turning around or shaking hands to walking to standing up or sitting down, etc. – not to mention aerobic exercise. Has anyone ever tried to tap that movement as an energy source? … [Yes.](https://news.vanderbilt.edu/2017/07/21/device-harvests-electricity-human-motion/) > [@](#): > > A new, ultrathin energy harvesting system developed at Vanderbilt University’s Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion. … > > … “Compared to the other approaches designed to harvest energy from human motion, our method has two fundamental advantages,” said Pint. “The materials are atomically thin and small enough to be impregnated into textiles without affecting the fabric’s look or feel and it can extract energy from movements that are slower than 10 Hertz—10 cycles per second—over the whole low-frequency window of movements corresponding to human motion.” … > > … One of the more futuristic applications of this technology might be electrified clothing. It could power clothes impregnated with liquid crystal displays that allow wearers to change colors and patterns with a swipe on their smartphone. “We are already measuring performance within the ballpark for the power requirement for a medium-sized low-power LCD display when scaling the performance to thickness and areas of the clothes we wear.” Pint said. … ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [November 24, 2017, 6:51pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/6 "2017-11-24T18:51:25Z")
There have been lots of ideas for [power generating shoes](https://www.google.com/search?source=hp&ei=2WkYWrP_C6nGjwSSibOAAg&q=power+generating+shoes). ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [November 24, 2017, 6:53pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/7 "2017-11-24T18:53:55Z")
> [@running\_coach](#): > > The problem is if you want to harvest the energy, you have to apply force to something. Just as an example, if you shake hands with someone, both hands would have to be attached to a rope/strap/whatever that turns a generator in order to use that energy. > > A treadmill, stationary bike or stairclimber could similarly be used to generate electricity. I suppose we can assume the wristwatch or telephone or whatever it is is attached to you or in a pocket so that it is subjected to acceleration and vibration as you walk around. The trick is to make such a thing so you would not even notice it; something that required, for instance, vigorous hand cranking would not qualify, unless I misunderstood the OP. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 24, 2017, 7:35pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/8 "2017-11-24T19:35:02Z")
If the device is getting useful work out, then you must be doing that much more work. That is to say, it’ll be harder to walk, and you’ll get tired more quickly, and so on. So it’s only viable in one of two cases: If the amount of energy needed is so small that you wouldn’t even notice (like with self-winding watches), or if the user doesn’t mind doing extra work. And if it’s the latter, then you don’t need to restrict yourself to incidental motion; you can have the person making extra movements they wouldn’t otherwise. The simplest way to implement this is to power your transportation with your own muscles, by walking or riding a bike in situations where you currently drive. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [November 24, 2017, 11:23pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/9 "2017-11-24T23:23:00Z")
How about “harvesting” the 500 calories I burn on my treadmill? ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [November 24, 2017, 11:25pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/10 "2017-11-24T23:25:57Z")
Naw, that idea will never take off. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [November 24, 2017, 11:29pm UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/11 "2017-11-24T23:29:07Z")
There’s a brief discussion of a movement powered system during this episode of “Wait Wait Don’t Tell Me” [Clippy And Paula : NPR](https://www.npr.org/2013/12/28/257559232/clippy-and-paula) - scroll down to the mention of “Twinkle, Twinkle” ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [November 25, 2017, 12:25am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/12 "2017-11-25T00:25:36Z")
I thought this thread was going to be about harnessing the power of [another sort of human movement](https://www.theguardian.com/environment/2016/jan/16/colorado-grand-junction-persigo-wastewater-treatment-plant-human-waste-renewable-energy). ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [November 25, 2017, 12:40am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/13 "2017-11-25T00:40:08Z")
> [@Chronos](#): > > … it’s only viable in one of two cases: If the amount of energy needed is so small that you wouldn’t even notice (like with self-winding watches), or if the user doesn’t mind doing extra work. … Or if it is work that would be done in any case. Clothing bends, shoes absorb the force of impact, in any case, with the work otherwise being lost as heat. The idea can be similar to regen braking. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [November 25, 2017, 1:18am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/14 "2017-11-25T01:18:26Z")
I have always felt that small storage batteries charged by skateboards, bikes would be handy for small electronic devices. A device kind of like those tops we used to push on to make spin could be built into shoes. a once inch power stroke would take some getting used to. ---
**Author:** ![Dendarii\_Dame](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@Dendarii\_Dame](https://boards.straightdope.com/u/Dendarii_Dame)\ **Post date:** [November 25, 2017, 1:21am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/15 "2017-11-25T01:21:40Z")
In at least one science fiction novel, _Portal to E’ewere_ by Irma Walker, people create energy by pedaling stationary bicycles for hours at a time in a dystopian future. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [November 25, 2017, 1:23am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/16 "2017-11-25T01:23:25Z")
> [@DSeid](#): > > Or if it is work that would be done in any case. Clothing bends, shoes absorb the force of impact, in any case, with the work otherwise being lost as heat. The idea can be similar to regen braking. No, even if a movement would be done anyway, harvesting energy means it will take more effort to make that same movement. A piece of clothing that generates electricity from movement would be stiffer than conventional clothing, requiring more effort to bend your arms or legs. Walking with energy-absorbing shoes will take more effort. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [November 25, 2017, 1:26am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/17 "2017-11-25T01:26:42Z")
> [@HoneyBadgerDC](#): > > I have always felt that small storage batteries charged by skateboards, bikes would be handy for small electronic devices. Dynamos on bikes are pretty common, and there are [many dynamo-powered USB chargers and charging systems](https://www.cyclingabout.com/list-of-hub-dynamo-power-supplies-for-usb-devices/) available. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [November 25, 2017, 1:39am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/18 "2017-11-25T01:39:25Z")
> [@DSeid](#): > > Or if it is work that would be done in any case. Clothing bends, shoes absorb the force of impact, in any case, with the work otherwise being lost as heat. The idea can be similar to regen braking. > [@scr4](#): > > No, even if a movement would be done anyway, harvesting energy means it will take more effort to make that same movement. A piece of clothing that generates electricity from movement would be stiffer than conventional clothing, requiring more effort to bend your arms or legs. Walking with energy-absorbing shoes will take more effort. The truth is sorta in the middle. If no changes are made to the clothes or shoes, then the harvesting system’s energy take-off will be in addition to the energy converted to heat in the clothes or shoes. Then **scr4** ’s answer will apply perfectly. IOW, he’s got the underlying principles right, but maybe not the real-world details. Part of the design of current shoes is to provide X amount of cushioning and impact absorbance. Right now the only way to dissipate that energy absorption is as heat. \*If \*we can convert some of that energy to electricity directly, we can scrimp on the remaining part that wastes the rest as heat. Resulting in the same mechanical outcome and no extra human effort needed to walk. Plus, as **Chronos** almost said, if the incremental effort is small enough it _practically speaking_ won’t matter. Yes, there is no free lunch or perpetual motion machine here. But if we’re only trying to harvest a few milliwatts of power with a pair of shoes, and we unsmartly do that in addition the ordinary friction of ordinary shoes, then a healthy adult still will never notice the difference. Walking into a 1/4mph breeze or up a 1" per mile slope will be larger energy draws than that. This is also where a hand-cranked LED flashlight works a lot better than a hand-cranked incandescent one. The progress in the rest of our electronics towards low power consumption certainly helps reduce the demand for power down to the level that it might be lost in the sauce. You could never operate a WWII walkie talkie off impreceptable amounts of human effort. You might be able to operate a modern GPS navigator off imperceptible amounts. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [November 25, 2017, 4:00am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/19 "2017-11-25T04:00:48Z")
> [@LSLGuy](#): > > Part of the design of current shoes is to provide X amount of cushioning and impact absorbance. Right now the only way to dissipate that energy absorption is as heat. This isn’t quite true. An elastic material (metal springs, elastic rubber soles, etc) can absorb impact by deforming, and the energy is stored mechanically, not dissipated. The energy is then used to propel the wearer forward in the next step. If that energy is instead converted into electricity, that would slow down the wearer. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [November 25, 2017, 4:54am UTC](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610/20 "2017-11-25T04:54:32Z")
> [@Dendarii\_Dame](#): > > In at least one science fiction novel, _Portal to E’ewere_ by Irma Walker, people create energy by pedaling stationary bicycles for hours at a time in a dystopian future. And animals make them do it–kind of like _The Flintstones_, reversed? [Next page](https://boards.straightdope.com/t/harvesting-human-movement-energy/802610.md?page=2)