How much energy can be harnessed from human activity?

Question

I remember reading about a new technology that uses the energy imparted by pedestrians on a sidewalk to power the overhead lights. How much energy can really be harnessed from human activity? for example, Could one man turn a crank for a few hours to power a battery of somesort that can be used for practical power?

thanks nickel great info Amazing how much more energy we use than even the ancient castle builders, who probably worked their arses off.

Answer 1

there are lots of hippies and "back to earthers" who use human power for the things they need, like hooking up an old bicycle to run the television. apparently it does not take that much power, just a slow pedal to keep a tv lit up. I am always reading about people doing this in alternative magazines and in magazines like mother earth news.
and why do the new treadmills all have electric motors. would it not be better for the old ones where you had to actually move to make the rubber mat thing move as you tried to walk forward.

Answer 2

I have seen pedal powered laptops, and I have been on the Rinky Dink music machine, that is a pedal powered (2 people pedalling) sound system. It's amazing how much work the bass line takes, at a good volume you only last one tune and then you are knackered.

What I want to to know is if you use energy from a person as do when you put two anodes into a potato or water to power an lcd clock or such like.

Answer 3

According to "Klaus Heinloth" in his book "Die Energiefrage", the average power used by a man through history was:
- 0.1 kW for a gatherer-hunter (only survival)
- 1 kW during the large construction period in the middle age (castles, cathedrals, etc...)
- 6 kW per capita on average nowadays in developped countries (this already includes the massive consumption of fossil fuels).

Let's use the 1 kW in the middle age knowing that this is a very harsh time and that the physical activity would be considered by our standards as close to slavery.

6 billion of people = 6.10^9 people proving each 1,000 Watt = 6,000 GW.

Our worldwide consumption of electricity is already over 3,000 GW. The worldwide energy consumption was in 2004 15,000 GW.

So we already consume twice of what we could reasonably produce.

This gap is even going to grow as the energy demand increases fast in emerging economies.


So I would say, NO it is technically impossible

Answer 4

A person can produce a negligible amount of power compared to what we use. Enough to power a flashlight but not a street light for example. They is why you actually see hand cranked flashlights and radios on the market (if you look for them), but there are no hand cracked room lights or refrigerators because those things require more power than a person can produce.

Answer 5

The Victorians used to get prisoners to turn cranks or walk up treadmills.
If you could assume that a human was 100% efficient then all of the calories they ate would be turned into motion but in reality a lot will be lost in heat.

Answer 6

Not enough.Maybe a time peace.

Answer 7

At my house, not much.