How green is our laptop?
ian.stirling at mauve.plus.com
Fri Sep 29 16:07:54 EDT 2006
Jim Gettys wrote:
> We've been very concerned about the "green" of our laptop, as we know
> that it may not be recycled properly. Obviously, a smaller/lighter/more
> rugged/longer lived machine has a lot of advantages as well in this area
> The very low power consumption of the machines means way less global
> warming due to electricity usage.
Beware, I'm bored, and have the Internet!
Say average child flatulence is 1l/day - sources I found said 200ml-2l,
I'm assuming 1l, as diets high in vegetables are more likely to cause an
Assuming that methane is 7%, this is about 150ml/day. (I found several
sources saying 7-9%, though some dismissed it as 'trace'. No primary
Assuming the '20 times more potent than CO2' is accurate - equivalent to
3l/day of CO2.
If we're talking 10Wh/day, how much of the food is used to produce
Well, if we're talking 1000Calories per day baseline food, that's
4MJ/day, or around 1% before taking into account human efficiencies. As
I see 25% as a rough 'maximum food conversion efficiency, that means
somewhere on the order of 4% more food, or 120g of CO2 equivalent per day.
(I'm assuming that the food is being produced in a carbon neutral manner.)
If you use this 120g of CO2 budget, and burn it in a modern gas power
station, you get about 300Wh. Using a coal power station, 100Wh.
Using an figure for a poorly maintained diesel generator (and neglecting
local emissions) it's still >90Wh.
I'd never have guessed.
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