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Re: Electrons



Laurent.
Actually a variant of the project is used here in Virginia. The
Bath County Pumped Storage facility uses night electricity (cheaper) to
pump water up into a dam impoundment. During the day the water is
released and used to generate electricity at more expensive rates. Try
http://www.harza.com/projects/bath.html for a fuller explanation. The
efficiency is reputed to be about 80%. The real economic impetus of the
project was to time-shift electrical energy production (think of it has
one huge honkin' battery) rather than actually make money from the
process.


THO

Thomas O'Neill
o'neill@csvrgs.k12.va.us
Physics
oneill@csvrgs.k12.va.us
C Shenandoah Valley R Governor's School 540.245.5088


-----Original Message-----
From: Laurent Hodges [mailto:lhodges@IASTATE.EDU]
Sent: Thursday, January 18, 2001 12:52 PM
To: PHYS-L@lists.nau.edu
Subject: Electrons

A state energy official, not a scientist, once asked me, obviously
puzzled,
this question: He knew that the transmission lines carried electrons
into
your house, but he wondered why there was no problem with the electrons
piling up in the house, or at least the last house on the line. I
started
to explain that first of all, the electric wires were double wires, and
he
struck his forehead and said, "Of course, the second wire is to carry
them
back."

Another state energy official, thinking about the problem of storing
energy
(like solar electric energy collected during daytime hours), once came
up
with this idea, which really excited him: Use the excess to lift heavy
weights (like steel bars) into the air, and retrieve their
(gravitational
potential) energy by lowering them again. I did a back-of-the-envelope
calculation, which you might like to reproduce, to show him what would
be
entailed in storing, say, one million Btu (approximately one billion
joules), what a house might use for heating on a cold night. He gave up
on
the idea.

Laurent Hodges