5 ms·

>So society's computer uses 5 percent and our own, evolved over millions of years, uses up to 20. This comparison doesn't make a lot of sense to me. It's not e

by simias 8y ago

>So society's computer uses 5 percent and our own, evolved over millions of years, uses up to 20. This comparison doesn't make a lot of sense to me. It's not even comparing apples to oranges, it's comparing apples to the concept of taste. Furthermore these percentages don't really tell you much regarding efficiency, I'm sure there are less developed societies where computers count for less than 5% of all energy consumption, doesn't mean that their computers are more efficient.

acallan 8y ago
Calories and can be converted to Joules. The amount of energy to run a computer (a human computer or a physical one) is interesting to me personally, as is comparing the amount of extra calories (and thus, extra emissions) it costs me to ride my bike 20 miles to work vs. driving a gasoline car.
- fovc 8y ago
  Agriculture + metabolism has a much lower emissions per km than gas powered cars. Also, your emissions are ultimately plant based, so the only real net emissions are due to producing fertilizers and machinery for agriculture and the embedded emissions in your bike, to the extent those are oil/gas/coal based. [1] https://ecf.com/news-and-events/news/how-much-co2-does-cycling-really-save https://ecf.com/news-and-events/news/how-much-co2-does-cycli...
cfallin 8y ago
Why not, though? Energy is energy -- we (humans) oxidize food, basically burning it slowly, to power our bodies. Whether the energy is carried by glucose/ATP or electric current is just an implementation detail. Comparisons are frequently made in other domains as well -- e.g., cyclists measure power outputs in watts. The rule of thumb I've understood is that the brain runs on about 20 watts (peak power), and a human on average runs on about 100 watts. That's 8.64 MJ/day, which converts to 2064 food calories (kcal), at 4184 J/kcal.
- peeters 8y ago
  One is saying how much computers use of a global resource pool, the other is how much brains use of their host body. They're completely different things so it doesn't make sense to compare those two percentages. If you wanted to compare them, cite the percent that the CPU uses of its PSU, or cite the percent that human brains use of global energy consumption. Otherwise they're completely different things that have no meaning in relation to each other.
  - mcbits 8y ago
    One is viewing society as a "body" with computers being its "brain". The other is viewing the human body as a "body" with its brain being its "brain". The comparison is of the energy used by each "brain" relative to the total energy used by its "body". The comparison is valid if you accept the analogy, although I think you could easily dispute the analogy. E.g. you could just as easily view the network of humans in a society as its "brain" and all the things we build (including computers) as its "body".
    - pessimizer 8y ago
      > you could just as easily view the network of humans in a society as its "brain" You could far more easily view the brains of humans in a society as its "brains."
  - devmacrile 8y ago
    Exactly. It's a meaningless and even misleading analogy. If forced to draw a comparison, you could maybe talk about the energy dissipation of a single neuron and compare that to, say, the energy dissipation of a single transistor. And in that case, considering a human brain is powered by something on the order of 10^10 neurons, the energy efficiency of the brain comes out looking pretty good.
- mmt 8y ago
  > Energy is energy Even this isn't quite true, since it's not fungible, except in the narrow use-case of creating heat[1]. > Whether the energy is carried by glucose/ATP or electric current is just an implementation detail. This implementation detail means that converting between these forms incurs a tremendous cost (in lost energy) and, perhaps more importantly, is nowhere near instantaneous. [1] Even the slightly broader use case of heating (e.g. increasing the temperature of a home) can be done with a heat pump, and those don't tend to run off of fungible energy.
sixstringtheory 8y ago
I second this, in order for it to be a fair comparison we have to level the playing field, by converting the total available calories (for humans) and electricity (for computers) into some common unit that represents the total capacity available to the US (or world). Another commenter brought up Joules which I think would work, I just can’t fully wrap my mind around what all will go into the calculation, like food growing and transport energy requirements, vs power plant emissions, maintenance, coal/oil transport.

by simias 8y ago

acallan 8y ago

Calories and can be converted to Joules. The amount of energy to run a computer (a human computer or a physical one) is interesting to me personally, as is comparing the amount of extra calories (and thus, extra emissions) it costs me to ride my bike 20 miles to work vs. driving a gasoline car.

fovc 8y ago
Agriculture + metabolism has a much lower emissions per km than gas powered cars. Also, your emissions are ultimately plant based, so the only real net emissions are due to producing fertilizers and machinery for agriculture and the embedded emissions in your bike, to the extent those are oil/gas/coal based. [1] https://ecf.com/news-and-events/news/how-much-co2-does-cycling-really-save https://ecf.com/news-and-events/news/how-much-co2-does-cycli...

cfallin 8y ago

Why not, though? Energy is energy -- we (humans) oxidize food, basically burning it slowly, to power our bodies. Whether the energy is carried by glucose/ATP or electric current is just an implementation detail. Comparisons are frequently made in other domains as well -- e.g., cyclists measure power outputs in watts. The rule of thumb I've understood is that the brain runs on about 20 watts (peak power), and a human on average runs on about 100 watts. That's 8.64 MJ/day, which converts to 2064 food calories (kcal), at 4184 J/kcal.

peeters 8y ago
One is saying how much computers use of a global resource pool, the other is how much brains use of their host body. They're completely different things so it doesn't make sense to compare those two percentages. If you wanted to compare them, cite the percent that the CPU uses of its PSU, or cite the percent that human brains use of global energy consumption. Otherwise they're completely different things that have no meaning in relation to each other.
- mcbits 8y ago
  One is viewing society as a "body" with computers being its "brain". The other is viewing the human body as a "body" with its brain being its "brain". The comparison is of the energy used by each "brain" relative to the total energy used by its "body". The comparison is valid if you accept the analogy, although I think you could easily dispute the analogy. E.g. you could just as easily view the network of humans in a society as its "brain" and all the things we build (including computers) as its "body".
  - pessimizer 8y ago
    > you could just as easily view the network of humans in a society as its "brain" You could far more easily view the brains of humans in a society as its "brains."
- devmacrile 8y ago
  Exactly. It's a meaningless and even misleading analogy. If forced to draw a comparison, you could maybe talk about the energy dissipation of a single neuron and compare that to, say, the energy dissipation of a single transistor. And in that case, considering a human brain is powered by something on the order of 10^10 neurons, the energy efficiency of the brain comes out looking pretty good.
mmt 8y ago
> Energy is energy Even this isn't quite true, since it's not fungible, except in the narrow use-case of creating heat[1]. > Whether the energy is carried by glucose/ATP or electric current is just an implementation detail. This implementation detail means that converting between these forms incurs a tremendous cost (in lost energy) and, perhaps more importantly, is nowhere near instantaneous. [1] Even the slightly broader use case of heating (e.g. increasing the temperature of a home) can be done with a heat pump, and those don't tend to run off of fungible energy.

sixstringtheory 8y ago

I second this, in order for it to be a fair comparison we have to level the playing field, by converting the total available calories (for humans) and electricity (for computers) into some common unit that represents the total capacity available to the US (or world). Another commenter brought up Joules which I think would work, I just can’t fully wrap my mind around what all will go into the calculation, like food growing and transport energy requirements, vs power plant emissions, maintenance, coal/oil transport.