6 ms·

This will never, ever make economic sense. Human labor is orders of magnitude too valuable to waste on power generation. A fit man can, in an hour, produce abou

This will never, ever make economic sense. Human labor is orders of magnitude too valuable to waste on power generation. A fit man can, in an hour, produce about 400 watt-hours of electricity, worth about $0.05; his labor would be worth at least $10 in a developed country. In the unlikely event that all modern technology ceased to exist, we would revert to using animals and wood for power, like they did in the 1700s.

brohee 9y ago
Someone producing 400W for an hour is not a fit man, it's a star endurance athlete. It's the kind of power top performer in tour de France can provide.
- ptaipale 9y ago
  Indeed. At a local nuclear power station there's a visitor center where one can experiment how to generate electricity with an exercise bike. With moderate power you can power a tablet computer or an incandescent light bulb, but the water kettle comes on only with actual athletes, and even then, the small light bulb goes off, and even a professional cyclist can't sustain that power for longer than a brief moment. It's just pointless to generate electricity by human power. It's not pointless to ride a bike.
  - diziet 9y ago
    Yes, as a benchmark an 80kg male rider that's an athlete but not a pro (say cat1 or cat2) can produce maybe 1200-1300 watts for 10 seconds, and maybe 400 watts or so for 5 minutes.
- pipio21 9y ago
  Not to mention that a Tour de France Athlete is consumed during the Tour. You need to accumulate reserves for at least three months in order to last 23 days of effort.
  - jackmott 9y ago
    they could do 400 watts for one hour a day indefinitely though.
    - thrownblown 9y ago
      Bradley Wiggins in the most recent hour record attempt averaged 440 for an hour. 440 watts for a world hour record. 350 watts for one hour, once a day, would be challenging to maintain for one week.
- workerIbe 9y ago
  On a good day my house uses 8kwh, I suppose I'd qualify as an endurance athelete after pedaling 20hrs a day for a bit.
- dmurdoch 9y ago
  It takes an Olympic Cyclist mashing until he has to lie down just to make a piece of toast. https://www.youtube.com/watch?v=S4O5voOCqAQ https://www.youtube.com/watch?v=S4O5voOCqAQ
Asooka 9y ago
Not to mention that muscle is really really bad at energy conversion. We would be better off designing bacteria to turn plant matter into gas.
masklinn 9y ago
> A fit man can, in an hour, produce about 400 watt-hours of electricity That's not "a fit man" that's a trained and fit cyclist, good marathon runners (2h15) were measured at an average 300W over the run[0], a fit adult might reach 200W.h over an hour or two, over long periods of time (e.g. an entire workday) you won't get much more than 100W.h if even that, an average fit labourer would be around 75W.h. And that's mechanical in all cases, not electrical, you then have to factor in conversion losses. While a large rotary generator is ridiculously efficient (98~99%) it doesn't scale down that well (you'll be at about 80~90% at the generator output) following which you still need to remove the losses from the voltage regulator, battery, and possibly AC converter. And then you still have the issue that your base energy sources (people) is not really efficient at converting food to mechanical energy in the first place. Frankly, you'd be better off with a team of draft animals powering a big crank/wheel (with a flywheel for regulation), the average draft horse can produce ~740W (1hp) sustained. There's a reason why they (and oxen and other beasts of burden) have been used until engines became a thing. [0] http://running.competitor.com/2016/11/photos/understanding-running-power-marathon-via-stryd-data_158787 http://running.competitor.com/2016/11/photos/understanding-r...
- baddox 9y ago
  Yeah, I was humbled by the claim that a fit man can produce 400 watt hours in an hour. I was recently struggling to hit 550 watts PEAK doing row machine intervals for 10 minutes.
  - Someone 9y ago
    That's not surprising. If you do 550W consistently during 6 minutes, you do 500m splits of 1:26 (http://www.concept2.com/indoor-rowers/training/calculators/watts-calculator http://www.concept2.com/indoor-rowers/training/calculators/w...), or a 2000m in 5:44, which is 'only' 6 seconds from the world record (http://www.concept2.com/indoor-rowers/racing/records/world/2000 http://www.concept2.com/indoor-rowers/racing/records/world/2...), and would probably draw the attention of most Olympic rowing teams, even if you can't row at all currently (for the larger boats, it is easier to learn a strong man who is willing to do a 2k that fast to row than to make someone who can row that strong and/or that motivated to compete) ('Only' because you need to do 580W to gain those six seconds. 2% faster = 6% more power)
mowenz 9y ago
This is True, but just for genetating and selling electricity on a market. By contrast, Cycling or taking stairs can still make great economic sense, or even much better sense, than driving, when deciding to produce or purchase energy.
- photojosh 9y ago
  I sold our 2nd car, and just ride to work now. But if we just compare human fuel aka food with vehicle fuel, it's actually more expensive to ride! But it's all the other costs of owning a car that make it so much more expensive: depreciation, licensing, registration, maintenance, blah, blah.
  - mowenz 9y ago
    Hmm depends on which fuel you choose to fill up with. Assuming we choose the cheapest option, a litre of clean burning canola oil can carry you 91km assuming 30 calories/km and 2750 calories/litre @ <$2/L that's a lot better than a car even before ownership and other per mile costs. But most people are in an unwanted caloric surplus so it's really even better than this for those people.
    - photojosh 9y ago
      I'm in Australia, and in our car it works out to about A$0.13/km in fuel. So yeah, you're right there. I choose not to drink pure canola oil because reasons. But if I did, my ride to work would be fueled by 30mL - so I could maybe just start taking a shot in the morning and a shot in the evening. Yummy.
      - mowenz 9y ago
        Haha - well if we're going to talk about practicality - it doesn't need to be as tasteless as that - it reminds me of the ultra endurance swimmers sucking hot oil through a tube. You can just make some delicious fried or oily snack, like crisps or chips or sauteed spinach, or fried what-have-you. ...but even a shot of oil is more healthy, pleasurable and hygenic (assuming you burn it all) than filling your tank with petrol :)
jlebrech 9y ago
you can pay obese people to lose weight, but you can't have something like that everywhere.
- zdkl 9y ago
  Stairs on one side and something like a waterwheel on the other. Charge less than a gym and sell it as partially powering whatever local association/charity could do with a break. Credit me when it's a thing heh
  - govg 9y ago
    Proceeding along this train of thought, they've already made a TV show episode out of it : https://en.wikipedia.org/wiki/Fifteen_Million_Merits https://en.wikipedia.org/wiki/Fifteen_Million_Merits
  - davnicwil 9y ago
    I know this is a joke, but I wonder if this concept - a gym where the machines generate power - actually could be a thing. It's greener in a pleasantly 'immediate' way - i.e. you could quite literally be keeping the lights, music system, etc on at the gym :-) And what's more, assuming power costs are a non-trivial overhead, it could even result in lower membership fees. If somebody opens a gym like this, sign me up!
    - jlebrech 9y ago
      that would be cool, you power the batteries and those batteries light up the gym and power the usb sockets the the user's phones.
    - gambiting 9y ago
      The gym that I go has machines that are almost all self-powered, with the exception of things like thread mils for obvious reasons. So if you jump on a stationary bike none of the electronics will turn on unless you start pedaling, and to get the fan going you have to pedal for a minute or so first.
    - 9y ago
300bps 9y ago
You're right that it doesn't make economic sense. It also doesn't make scientific sense. First of all, human power releases tons of carbon dioxide just like burning fossil fuels does [0]. Second of all, modern society currently depends on burning millions of years of stored sunlight energy in a matter of centuries (i.e. fossil fuels). Human power doesn't begin to compare. Bang Goes The Theory (BBC show) did an entire episode on this. It's shocking how many bicyclists were needed to run a tiny household [1]. --- [0] http://www.livestrong.com/article/402142-how-does-exercise-affect-breathing/ http://www.livestrong.com/article/402142-how-does-exercise-a... [1] https://m.youtube.com/watch?v=vPxuuB_ZBuk https://m.youtube.com/watch?v=vPxuuB_ZBuk
- scarmig 9y ago
  The carbon that humans exhale is already part of the carbon cycle. So equilibrium CO2 concentrations don't change, so it's not an issue pollution wise. (This is assuming you didn't use a bunch of fossil fuels to create and transport food in the first place, and you're instead using human/animal power to do that.)
  - kristjansson 9y ago
    However, using humans as power source would increase the amount of food consumed, and co2 exhaled, so this analysis would need to take at least that incremental co2 into account.
    - deleted 9y ago
      [deleted]
    - ouid 9y ago
      Whether a human eats the plant or it decomposes naturally, the same amount of carbon dioxide is released.
      - erroneousfunk 9y ago
        That would be fine if humans simply walked around consuming plants that would have otherwise decomposed and there were no other resources associated with food production. Unfortunately, agriculture is a major driver of deforestation (and forests are excellent at actually sequestering carbon in the ground). It also requires trucks, boats, and planes to haul supplies to farms, work the land, move water around, and transport the produce to stores. You have processing and packaging that rely on fossil resources (paper, plastic, metal cans...) That doesn't even touch on the impact of meat production, which is several times worse for the environment. Food consumption is absolutely not carbon neutral. You're far better off taking public transportation to work (if available) than walking or riding a bike, if you care about the environment.
tinus_hn 9y ago
Note that people pay to waste their energy in gyms.

brohee 9y ago

Someone producing 400W for an hour is not a fit man, it's a star endurance athlete. It's the kind of power top performer in tour de France can provide.

ptaipale 9y ago
Indeed. At a local nuclear power station there's a visitor center where one can experiment how to generate electricity with an exercise bike. With moderate power you can power a tablet computer or an incandescent light bulb, but the water kettle comes on only with actual athletes, and even then, the small light bulb goes off, and even a professional cyclist can't sustain that power for longer than a brief moment. It's just pointless to generate electricity by human power. It's not pointless to ride a bike.
- diziet 9y ago
  Yes, as a benchmark an 80kg male rider that's an athlete but not a pro (say cat1 or cat2) can produce maybe 1200-1300 watts for 10 seconds, and maybe 400 watts or so for 5 minutes.
pipio21 9y ago
Not to mention that a Tour de France Athlete is consumed during the Tour. You need to accumulate reserves for at least three months in order to last 23 days of effort.
- jackmott 9y ago
  they could do 400 watts for one hour a day indefinitely though.
  - thrownblown 9y ago
    Bradley Wiggins in the most recent hour record attempt averaged 440 for an hour. 440 watts for a world hour record. 350 watts for one hour, once a day, would be challenging to maintain for one week.
workerIbe 9y ago
On a good day my house uses 8kwh, I suppose I'd qualify as an endurance athelete after pedaling 20hrs a day for a bit.
dmurdoch 9y ago
It takes an Olympic Cyclist mashing until he has to lie down just to make a piece of toast. https://www.youtube.com/watch?v=S4O5voOCqAQ https://www.youtube.com/watch?v=S4O5voOCqAQ

Asooka 9y ago

Not to mention that muscle is really really bad at energy conversion. We would be better off designing bacteria to turn plant matter into gas.

masklinn 9y ago

> A fit man can, in an hour, produce about 400 watt-hours of electricity That's not "a fit man" that's a trained and fit cyclist, good marathon runners (2h15) were measured at an average 300W over the run[0], a fit adult might reach 200W.h over an hour or two, over long periods of time (e.g. an entire workday) you won't get much more than 100W.h if even that, an average fit labourer would be around 75W.h. And that's mechanical in all cases, not electrical, you then have to factor in conversion losses. While a large rotary generator is ridiculously efficient (98~99%) it doesn't scale down that well (you'll be at about 80~90% at the generator output) following which you still need to remove the losses from the voltage regulator, battery, and possibly AC converter. And then you still have the issue that your base energy sources (people) is not really efficient at converting food to mechanical energy in the first place. Frankly, you'd be better off with a team of draft animals powering a big crank/wheel (with a flywheel for regulation), the average draft horse can produce ~740W (1hp) sustained. There's a reason why they (and oxen and other beasts of burden) have been used until engines became a thing. [0] http://running.competitor.com/2016/11/photos/understanding-running-power-marathon-via-stryd-data_158787 http://running.competitor.com/2016/11/photos/understanding-r...

baddox 9y ago
Yeah, I was humbled by the claim that a fit man can produce 400 watt hours in an hour. I was recently struggling to hit 550 watts PEAK doing row machine intervals for 10 minutes.
- Someone 9y ago
  That's not surprising. If you do 550W consistently during 6 minutes, you do 500m splits of 1:26 (http://www.concept2.com/indoor-rowers/training/calculators/watts-calculator http://www.concept2.com/indoor-rowers/training/calculators/w...), or a 2000m in 5:44, which is 'only' 6 seconds from the world record (http://www.concept2.com/indoor-rowers/racing/records/world/2000 http://www.concept2.com/indoor-rowers/racing/records/world/2...), and would probably draw the attention of most Olympic rowing teams, even if you can't row at all currently (for the larger boats, it is easier to learn a strong man who is willing to do a 2k that fast to row than to make someone who can row that strong and/or that motivated to compete) ('Only' because you need to do 580W to gain those six seconds. 2% faster = 6% more power)

mowenz 9y ago

This is True, but just for genetating and selling electricity on a market. By contrast, Cycling or taking stairs can still make great economic sense, or even much better sense, than driving, when deciding to produce or purchase energy.

photojosh 9y ago
I sold our 2nd car, and just ride to work now. But if we just compare human fuel aka food with vehicle fuel, it's actually more expensive to ride! But it's all the other costs of owning a car that make it so much more expensive: depreciation, licensing, registration, maintenance, blah, blah.
- mowenz 9y ago
  Hmm depends on which fuel you choose to fill up with. Assuming we choose the cheapest option, a litre of clean burning canola oil can carry you 91km assuming 30 calories/km and 2750 calories/litre @ <$2/L that's a lot better than a car even before ownership and other per mile costs. But most people are in an unwanted caloric surplus so it's really even better than this for those people.
  - photojosh 9y ago
    I'm in Australia, and in our car it works out to about A$0.13/km in fuel. So yeah, you're right there. I choose not to drink pure canola oil because reasons. But if I did, my ride to work would be fueled by 30mL - so I could maybe just start taking a shot in the morning and a shot in the evening. Yummy.
    - mowenz 9y ago
      Haha - well if we're going to talk about practicality - it doesn't need to be as tasteless as that - it reminds me of the ultra endurance swimmers sucking hot oil through a tube. You can just make some delicious fried or oily snack, like crisps or chips or sauteed spinach, or fried what-have-you. ...but even a shot of oil is more healthy, pleasurable and hygenic (assuming you burn it all) than filling your tank with petrol :)

jlebrech 9y ago

you can pay obese people to lose weight, but you can't have something like that everywhere.

zdkl 9y ago
Stairs on one side and something like a waterwheel on the other. Charge less than a gym and sell it as partially powering whatever local association/charity could do with a break. Credit me when it's a thing heh
- govg 9y ago
  Proceeding along this train of thought, they've already made a TV show episode out of it : https://en.wikipedia.org/wiki/Fifteen_Million_Merits https://en.wikipedia.org/wiki/Fifteen_Million_Merits
- davnicwil 9y ago
  I know this is a joke, but I wonder if this concept - a gym where the machines generate power - actually could be a thing. It's greener in a pleasantly 'immediate' way - i.e. you could quite literally be keeping the lights, music system, etc on at the gym :-) And what's more, assuming power costs are a non-trivial overhead, it could even result in lower membership fees. If somebody opens a gym like this, sign me up!
  - jlebrech 9y ago
    that would be cool, you power the batteries and those batteries light up the gym and power the usb sockets the the user's phones.
  - gambiting 9y ago
    The gym that I go has machines that are almost all self-powered, with the exception of things like thread mils for obvious reasons. So if you jump on a stationary bike none of the electronics will turn on unless you start pedaling, and to get the fan going you have to pedal for a minute or so first.
  - 9y ago

300bps 9y ago

You're right that it doesn't make economic sense. It also doesn't make scientific sense. First of all, human power releases tons of carbon dioxide just like burning fossil fuels does [0]. Second of all, modern society currently depends on burning millions of years of stored sunlight energy in a matter of centuries (i.e. fossil fuels). Human power doesn't begin to compare. Bang Goes The Theory (BBC show) did an entire episode on this. It's shocking how many bicyclists were needed to run a tiny household [1]. --- [0] http://www.livestrong.com/article/402142-how-does-exercise-affect-breathing/ http://www.livestrong.com/article/402142-how-does-exercise-a... [1] https://m.youtube.com/watch?v=vPxuuB_ZBuk https://m.youtube.com/watch?v=vPxuuB_ZBuk

scarmig 9y ago
The carbon that humans exhale is already part of the carbon cycle. So equilibrium CO2 concentrations don't change, so it's not an issue pollution wise. (This is assuming you didn't use a bunch of fossil fuels to create and transport food in the first place, and you're instead using human/animal power to do that.)
- kristjansson 9y ago
  However, using humans as power source would increase the amount of food consumed, and co2 exhaled, so this analysis would need to take at least that incremental co2 into account.
  - deleted 9y ago
    [deleted]
  - ouid 9y ago
    Whether a human eats the plant or it decomposes naturally, the same amount of carbon dioxide is released.
    - erroneousfunk 9y ago
      That would be fine if humans simply walked around consuming plants that would have otherwise decomposed and there were no other resources associated with food production. Unfortunately, agriculture is a major driver of deforestation (and forests are excellent at actually sequestering carbon in the ground). It also requires trucks, boats, and planes to haul supplies to farms, work the land, move water around, and transport the produce to stores. You have processing and packaging that rely on fossil resources (paper, plastic, metal cans...) That doesn't even touch on the impact of meat production, which is several times worse for the environment. Food consumption is absolutely not carbon neutral. You're far better off taking public transportation to work (if available) than walking or riding a bike, if you care about the environment.

tinus_hn 9y ago

Note that people pay to waste their energy in gyms.