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My favorite "genius idea" that comes up regularly is to have people running on treadmills and pedaling stationary bikes use the power they generate to power the

My favorite "genius idea" that comes up regularly is to have people running on treadmills and pedaling stationary bikes use the power they generate to power the gym or whatever. The amount of energy that treadmills and stationary bikes can generate from human power is absolutely trivial. Even given high electricity rates, it's worth about 3 cents an hour. The energy generated can barely power basic electronics on most self-powered exercise bikes.

biztos 7y ago
Also, treadmills aren't powered by the people on them, but rather use a lot of electricity to move the tread (and usually a tiny bit more for the electronics).
- narrator 7y ago
  They have self-powered treadmills. They're not very popular though: https://www.woodway.com/products/curve/ https://www.woodway.com/products/curve/
  - faceplanted 7y ago
    Yeah, they're really weird an uncomfortable until you get used to them, so people just see them as worse treadmills. All I really want is a stationary bike that powers a fan pointing at you to cool you down because I'm a sweaty bastard.
    - usrusr 7y ago
      That has been done many times. Products like Racermate Wind Load Simulator in the 1970ies, more recently the CycleOps Wind or the Lemond Revolution. In fact, all "trainer" devices where a regular bike is attached for indoor use are still colloquially called "turbos", in fierce defiance of Elon Musk's sudden love for semantic precision. They all suffered the same fate: when the hundreds of watts a well-trained athlete will produce during interval training is put into air movement, the noise is just unbearable. Much quieter setups are possible with more direct conversion to heat and even there, noise is still the dominant product metric.
fps_doug 7y ago
It's a cool DIY project though. I've been wanting to do this for ages (though I might want to get such a bike first and actually use it), and a while ago I saw this big nose YouTuber actually do this and they (barely) managed to run a gaming PC off of it. Which is a neat spin to the whole idea: No workout, no gaming.
mehrdadn 7y ago
> treadmills [...] use the power they generate to power the gym or whatever That's... not even wrong?
lnsru 7y ago
Don’t ignore aesthetics and installation costs of plug powered gym equipment vs. muscle powered equipment. Customer generated electricity allows to place equipment everywhere in the gym. Gym does not need power outlets for every piece of equipment and to have exact floor plan in the very beginning. Gym can rearrange equipment periodically delivering better experience for clients. You need 20 Watts to power Raspberry Pi running under load. Basic electronics with couple LEDs need only 3-5 Watts. Even less if designed properly, so this way generated energy can very well power gym equipment. I think, I can generate 100 Watts.
- masklinn 7y ago
  > I think, I can generate 100 Watts. > Over an 8-hour work shift, an average, healthy, well-fed and motivated manual laborer may sustain an output of around 75 watts of work. That's before conversion & transmission losses (especially as the converter will need to handle wildly varying inputs) And even if we ignore these, according to 10.1109/MSPEC.2011.5910449: > Let’s assume that the average piece of exercise equipment is in use 5 hours a day, 365 days a year. If each patron generates 100 watts while using it, that machine creates some 183 kilowatt-hours of electricity a year. Commercial power costs about 10 cents per kilowatt-hour on average in the United States, so the electricity produced in a year from one machine is worth about US $18 dollars.
  - jerf 7y ago
    Also, don't forget the gear to capture the electricity isn't free, is more stuff that can break and incur maintenance fees, must contain purified metals and other non-zero carbon emissions, and so on. Trying to break even on all of this off of human labor is a silly game to play when there are so many other better opportunities. And that $18/yr is already inflated by enough factors that $1/yr is probably a much better estimate. Same for these solar panels on a car, too. Solar panels aren't the nicest things to manufacture right now. Putting them on a platform this poor is silly when you could put them somewhere more effective. If they were dirt cheap and harmless to create, opportunity costs might be less of an issue, but even today, they aren't dirt cheap and the aren't harmless to manufacture. They should be used effectively, not for show or feelings.
walrus01 7y ago
ask a bike courier how much they spend on food each day, to maintain a 5000 calorie per day existence. Calories cost money.
- jdnenej 7y ago
  Hardly, you could easily cover any extra energy needs with a few spoonfuls of olive oil worth about $0.005
  - masklinn 7y ago
    GP is talking colloquially, they're talking about "large calories" (food calories, Calorie, …) aka 5000kcal. FDA recommendations is 2600kcal RDI for a healthy lightly active adult male. The "extra energy needs" is 2400kcal, olive oil is 884kcal/100g, that's 270g of olive oil, about 300ml. That's pounding down half a standard bottle every day, and at least a buck or two. Aside from getting cheap as hell olive oils, you seem to use ladles for spoons.
swebs 7y ago
My gym actually does that. The elliptical machines actually tell you how much power you're generating. Going at a moderate pace generates about 90 watts. That's enough to light up about 10 modern light bulbs. You're going to be generating that energy while working out anyway and it has to go somewhere. I think the biggest benefit is being able to direct where that energy dissipates. You can either put those 90 watts into the air as heat through friction, or put it into electricity through some dynamo. The second choice will make it so the place doesn't heat up as quickly.
- usrusr 7y ago
  > My gym actually does that. Do they really tell you how much energy they are harvesting as electricity or do they just tell you how much energy they are dissipating as heat? Because it is very common for sports equipment to measure/estimate the power applied by the athlete, in watts, all without the slightest trace of harvesting implied.
  - rypskar 7y ago
    The bike trainer I have tells how many watts I produce and how much is sent back to the grid, the number isn't high so is more geek stats than anything else
imtringued 7y ago
Most of the gym equipment I use, with the exception of treadmills and stair climbers, is powered by the operator. It only turns on after using it for half a minute. Phones and tablets need 10 watts or less. A notebook somewhere between 25 to 50 watts if it is running at 100% CPU. Why would an exercise machine with a similar screen size need more than that? Even a total beginner can generate far more than 50 watts.
protomok 7y ago
On a related note there's a pretty entertaining NPR video breaking down whether or not you can power your house with a bike - https://www.youtube.com/watch?v=xbUxt2x4InE https://www.youtube.com/watch?v=xbUxt2x4InE (spoiler alert - you can't :)) I worked it out and even if I pedal 8 hours / day and somehow convince the wife to join we're only producing 2kWh / day. Our house's power usage is ~11 kWh/day in the winter (worse in summer due to AC)...it's hopeless.

biztos 7y ago

Also, treadmills aren't powered by the people on them, but rather use a lot of electricity to move the tread (and usually a tiny bit more for the electronics).

narrator 7y ago
They have self-powered treadmills. They're not very popular though: https://www.woodway.com/products/curve/ https://www.woodway.com/products/curve/
- faceplanted 7y ago
  Yeah, they're really weird an uncomfortable until you get used to them, so people just see them as worse treadmills. All I really want is a stationary bike that powers a fan pointing at you to cool you down because I'm a sweaty bastard.
  - usrusr 7y ago
    That has been done many times. Products like Racermate Wind Load Simulator in the 1970ies, more recently the CycleOps Wind or the Lemond Revolution. In fact, all "trainer" devices where a regular bike is attached for indoor use are still colloquially called "turbos", in fierce defiance of Elon Musk's sudden love for semantic precision. They all suffered the same fate: when the hundreds of watts a well-trained athlete will produce during interval training is put into air movement, the noise is just unbearable. Much quieter setups are possible with more direct conversion to heat and even there, noise is still the dominant product metric.

fps_doug 7y ago

It's a cool DIY project though. I've been wanting to do this for ages (though I might want to get such a bike first and actually use it), and a while ago I saw this big nose YouTuber actually do this and they (barely) managed to run a gaming PC off of it. Which is a neat spin to the whole idea: No workout, no gaming.

mehrdadn 7y ago

> treadmills [...] use the power they generate to power the gym or whatever That's... not even wrong?

lnsru 7y ago

Don’t ignore aesthetics and installation costs of plug powered gym equipment vs. muscle powered equipment. Customer generated electricity allows to place equipment everywhere in the gym. Gym does not need power outlets for every piece of equipment and to have exact floor plan in the very beginning. Gym can rearrange equipment periodically delivering better experience for clients. You need 20 Watts to power Raspberry Pi running under load. Basic electronics with couple LEDs need only 3-5 Watts. Even less if designed properly, so this way generated energy can very well power gym equipment. I think, I can generate 100 Watts.

masklinn 7y ago
> I think, I can generate 100 Watts. > Over an 8-hour work shift, an average, healthy, well-fed and motivated manual laborer may sustain an output of around 75 watts of work. That's before conversion & transmission losses (especially as the converter will need to handle wildly varying inputs) And even if we ignore these, according to 10.1109/MSPEC.2011.5910449: > Let’s assume that the average piece of exercise equipment is in use 5 hours a day, 365 days a year. If each patron generates 100 watts while using it, that machine creates some 183 kilowatt-hours of electricity a year. Commercial power costs about 10 cents per kilowatt-hour on average in the United States, so the electricity produced in a year from one machine is worth about US $18 dollars.
- jerf 7y ago
  Also, don't forget the gear to capture the electricity isn't free, is more stuff that can break and incur maintenance fees, must contain purified metals and other non-zero carbon emissions, and so on. Trying to break even on all of this off of human labor is a silly game to play when there are so many other better opportunities. And that $18/yr is already inflated by enough factors that $1/yr is probably a much better estimate. Same for these solar panels on a car, too. Solar panels aren't the nicest things to manufacture right now. Putting them on a platform this poor is silly when you could put them somewhere more effective. If they were dirt cheap and harmless to create, opportunity costs might be less of an issue, but even today, they aren't dirt cheap and the aren't harmless to manufacture. They should be used effectively, not for show or feelings.

walrus01 7y ago

ask a bike courier how much they spend on food each day, to maintain a 5000 calorie per day existence. Calories cost money.

jdnenej 7y ago
Hardly, you could easily cover any extra energy needs with a few spoonfuls of olive oil worth about $0.005
- masklinn 7y ago
  GP is talking colloquially, they're talking about "large calories" (food calories, Calorie, …) aka 5000kcal. FDA recommendations is 2600kcal RDI for a healthy lightly active adult male. The "extra energy needs" is 2400kcal, olive oil is 884kcal/100g, that's 270g of olive oil, about 300ml. That's pounding down half a standard bottle every day, and at least a buck or two. Aside from getting cheap as hell olive oils, you seem to use ladles for spoons.

swebs 7y ago

My gym actually does that. The elliptical machines actually tell you how much power you're generating. Going at a moderate pace generates about 90 watts. That's enough to light up about 10 modern light bulbs. You're going to be generating that energy while working out anyway and it has to go somewhere. I think the biggest benefit is being able to direct where that energy dissipates. You can either put those 90 watts into the air as heat through friction, or put it into electricity through some dynamo. The second choice will make it so the place doesn't heat up as quickly.

usrusr 7y ago
> My gym actually does that. Do they really tell you how much energy they are harvesting as electricity or do they just tell you how much energy they are dissipating as heat? Because it is very common for sports equipment to measure/estimate the power applied by the athlete, in watts, all without the slightest trace of harvesting implied.
- rypskar 7y ago
  The bike trainer I have tells how many watts I produce and how much is sent back to the grid, the number isn't high so is more geek stats than anything else

imtringued 7y ago

Most of the gym equipment I use, with the exception of treadmills and stair climbers, is powered by the operator. It only turns on after using it for half a minute. Phones and tablets need 10 watts or less. A notebook somewhere between 25 to 50 watts if it is running at 100% CPU. Why would an exercise machine with a similar screen size need more than that? Even a total beginner can generate far more than 50 watts.

protomok 7y ago

On a related note there's a pretty entertaining NPR video breaking down whether or not you can power your house with a bike - https://www.youtube.com/watch?v=xbUxt2x4InE https://www.youtube.com/watch?v=xbUxt2x4InE (spoiler alert - you can't :)) I worked it out and even if I pedal 8 hours / day and somehow convince the wife to join we're only producing 2kWh / day. Our house's power usage is ~11 kWh/day in the winter (worse in summer due to AC)...it's hopeless.