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.
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.
> 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.
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.
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.
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.
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.
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.
That's... not even wrong?
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.