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Re: [Phys-l] Get Aggressive On Global Warming




----- Original Message ----- From: "John M Clement" <clement@hal-pc.org>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Thursday, April 19, 2007 3:57 PM
Subject: Re: [Phys-l] Get Aggressive On Global Warming


Good luck. The other thing that I start to wonder about if we
really start
thinking large scale wind (my project needs 1,500,000 1.5MW units in
place
by 2107 to handle 30% of the U.S. energy needs) is do we have enough
copper
for all these generators? I understand the big pit outside Salt
Lake City
is projected to start giving out pretty soon.

But doesn't it take just as much copper to make a conventional
generator? Maybe we will just have to melt down all of the pennies.
OOOPS, they are now made of zinc.

John M. Clement

Yes, but the problem here is that in order to stop using the fossil fuels
and use 'green' technologies like wind and solar, the end usage needs to be
moved to electrical usage. That's true even if you are thinking Hydrogen as
a fuel, you first need to make the electricity for 'clean' electrolysis. So
the bottom line here is that in terms of end-use, today's electrical usage
accounts for only about 20% of the total (gross energy resource use is
higher because of the Carnot efficiency losses using coal and natural gas
for something like 70% of our electricity). Consequently, in a 'brave, new,
clean" energy world, most of the end use (or steps to end use) energy needs
to be electrical--maybe all of it. So accounting for some improvements in
efficiency and efforts towards conservation, some gains in using electrical
energy say for motors, but also figuring in an increase in population, then
eliminating use of the fossil fuels means minimally a factor of 3 and maybe
a factor of 5 increase for electrical energy. So--that means a greatly
increased need for a lot of conducting wire for use in generators.

Rick