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On Sun, 31 Jul 2005 14:59:47 -0400, Slumlord
wrote:

~^Johnny^~ wrote:

On Thu, 28 Jul 2005 11:55:44 -0400, Slumlord
wrote:

Also during really hot weather, utilities will reduce voltage
about 5%.

I think that is an urban legend.

Its not an urban legend. If you check out PJM's website (thats the
grid for the mid Atlantic states), part of their emergency
procedures, during periods of very high load, is to drop the
voltage on the system by 5%. Its the last step before they initiate
rolling blackouts

OK, I'm convinced, but that's crazy. The maximum theoretical power
savings would be 9.75%, in a purely resistive (heating) load, with
no motors or computers, etc.

Most computer switching supplies, ac motors, etc, will simply draw
more current as the mains potential drops. All cutting the voltage
wilt do is dim the lights, and they'd be lucky to save 3 or 4% at
the most in the process, with rolling blackouts (rotating outages)
imminent anyway.

During our last power shortage here on the west coast, PG&E actually
had informed the media of which Rotating Outage blocks were scheduled
for blackout. With, like, 30 or so RO blocks in most areas, the
threat of blackouts wasn't much of a deterrent, because the
customers in the rest of the blocks knew they would not lose service
during that particular scheduled outage.

If they would black out the blocks at random, with little or no
notice, it would be a much greater deterrent to excessive usage, as
everybody would cut back - not just those in the next few scheduled
RO blocks.

And I don't buy the arg "they have to give customers ample notice
before disconnect..."; it is, after all, an emergency.

my two cents


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--
-john
wide-open at throttle dot info