Difference between revisions of "Muscle power versus modern consumption"

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[[Category:Energy Use]]
 
[[Category:Energy Use]]
  
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>
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Energy guru [https://www.sciencemag.org/news/2018/03/meet-vaclav-smil-man-who-has-quietly-shaped-how-world-thinks-about-energy Vaclav Smil]<ref>
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''See also''
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"Meet Vaclav Smil, the man who has quietly shaped how the world thinks about energy"
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by Paul Voosen,
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in AAAS Science magazine,
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on 21 Mar 2018,
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[https://www.sciencemag.org/news/2018/03/meet-vaclav-smil-man-who-has-quietly-shaped-how-world-thinks-about-energy [article]]
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</ref>
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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 - A Beginner's Guide" by Vaclav Smil, Oneworld Publications, 2006 - 2017, ISBN 978-1-78607-133-0, page 71</ref>
 
"Energy - A Beginner's Guide" by Vaclav Smil, Oneworld Publications, 2006 - 2017, ISBN 978-1-78607-133-0, page 71</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 19:29, 23 May 2020


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

Energy guru Vaclav Smil[1] 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.[2]

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.[3]

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. See also "Meet Vaclav Smil, the man who has quietly shaped how the world thinks about energy" by Paul Voosen, in AAAS Science magazine, on 21 Mar 2018, [article]
  2. "Energy - A Beginner's Guide" by Vaclav Smil, Oneworld Publications, 2006 - 2017, ISBN 978-1-78607-133-0, page 71
  3. Smil, op cit, page 81