Difference between revisions of "Muscle power versus modern consumption"

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[[Category:Energy Use]]
 
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How much power can humans, and other animals, generate?
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'''How much power can humans, and other animals, generate, and how much do we consume?'''
How much do we consume?
 
  
 
Energy guru Vaclav Smil claims that trained individuals can generate 4 or even 5{{sp}}KW of work for a few seconds, and almost 2{{sp}}KW equivalent in sustained running.<ref>
 
Energy guru Vaclav Smil claims that trained individuals can generate 4 or even 5{{sp}}KW of work for a few seconds, and almost 2{{sp}}KW equivalent in sustained running.<ref>
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One horsepower is defined as 745{{sp}}Watts, and good horses can sustain 700&mdash;800{{sp}}W of work power. Oxen, by comparison, may be capable of only around 300{{sp}}W for smaller animals.<ref>
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One horsepower is defined as 745{{sp}}Watts, and good horses can sustain 700&mdash;800{{sp}}W of work power, so they could easily run a toaster. Oxen, by comparison, may be capable of only around 300{{sp}}W for smaller animals.<ref>
 
Smil, ''op cit'', page 81</ref>
 
Smil, ''op cit'', page 81</ref>
  

Revision as of 18:24, 23 May 2020


How much power can humans, and other animals, generate, and how much do we consume?

Energy guru Vaclav Smil claims that trained individuals can generate 4 or even 5 KW of work for a few seconds, and almost 2 KW equivalent in sustained running.[1]

However a practical experiment finds that an Olympic cyclist struggles to generate enough power to run a 700 W toaster for a couple of minutes:

One horsepower is defined as 745 Watts, and good horses can sustain 700—800 W of work power, so they could easily run a toaster. Oxen, by comparison, may be capable of only around 300 W for smaller animals.[2]

How much power do we use?

How does this compare with the amounts of power we are accustomed to using as part of a first-world lifestyle? Toasters are amongst the more power-hungry machines we use, along with others that produce heat such as kettles, dishwashers, washing machines, and heaters of course. Mobile phones, tablets and laptops, and modern energy-efficient LED lights use relatively little, although a dozen halogen downlighters draw almost as much as a toaster.

BBC TV's "Bang Goes The Theory" conducted a practical demonstration, showing how much electricity we use (and abuse!) without even thinking about it. This massive experiment attempted to power a house for an entire day solely through human pedal power, while the unsuspecting family inside went about their normal Sunday routine:

Spoiler: here's what happened when one of the family used their electric shower:

Electric showers are the most power-hungry electrical appliances we use in our homes, but anyone with a gas "combi" boiler uses three times as much whenever they run a hot tap to fill a bath, or when the central heating is running on a cold day.

Footnotes and references

  1. "Energy - A Beginner's Guide" by Vaclav Smil, Oneworld Publications, 2006 - 2017, ISBN 978-1-78607-133-0, page 71
  2. Smil, op cit, page 81