From: ronkean@juno.com
Date: Wed Sep 01 1999 - 00:09:22 MDT
On Tue, 31 Aug 1999 07:04:04 -0700 (PDT) "Robert J. Bradbury"
<bradbury@www.aeiveos.com> writes:
>
I'd stick by my belief
> that most homes don't come close to using this (I suppose I could
> figure it out from my electric bill).
>
The CIA keeps track of electricity capacity and production data for each
country, which they publish in 'The World Factbook' each year. The 1992
Factbook reports 12,080 kWH annual per capita US production for 1990, and
the 1995 Factbook reports 11,236 kWH annual per capita US production for
1993. 11,236 kWH / 8760 hours = 1283 watts per person average rate of
production (1993). This does not account for imports and exports of
electricity, but does include industrial and infrastructure consumption
(e.g. streetlights) as well as transmission and distribution waste heat.
US generating capacity is 2545 watts per person. So the system normally
operates at about 50% of capacity. The URL for that CIA data is
http://www.odci.gov, where you should be able to get more recent info if
you like.
According to a recent electric bill, my house consumed an average of 482
watts during the period June 4 to July 6 this year. This is a miniscule
2% of the 24 kW feed rating (240 volts, 100 amps).
[Ron]
> > Those numbers work out to 5.7x10^4 KW per person, modeling the
> earth as a> > disk of the given radius, facing the sun. But the
earth's
> population is> > now reported to be 6 billion rather than 3 billion.
>
> We must be using different calculators because when I take
> Insolation*Pi*R_earth^2 / 6*10^9
> I get 2.93*10^7.
>
The 5.7x10^4 kW I calculated is for 3 billion people, just using the
original figures quoted, and ignoring the fact that 3 billion is not
really the correct population figure. But the population is really 6
billion, so the answer should be about 2.9x10^4 kW, using a 6 billion
population. The 2.93x10^7 figure you got is watts, not kilowatts. It
very nearly equals the 2.9x10^4 kW figure.
Ron Kean
.
.
.
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