wrote:
On Wed, 7 Nov 2007 20:35:32 +0000 (UTC), (Dave
Martindale) wrote:

"geothermaljones" writes:

See, DC is a much more efficient powersource when use in close
proximity of production.

DC *at the voltage you happen to need* is more efficient than AC,
because there are no transformer losses. But if the voltages don't
match, it's much more complicated and expensive to change voltage
with DC.

Unfortunately the DC supply to a power grid in an urban area would
require huge quantities of copper to transmit.
Now if they'd just have used more localized transformers &
generation, we'd all be saving energy.

There are probably only a few houses sharing the same pole
transformer (and thus the same 120/240 V supply). All other
distribution is done at higher voltage. To get the same efficiency
(both electric and copper usage) with DC, you'd need a source for
every few houses. But generators that small aren't very clean or
efficient.

Centralized generation and AC distribution, using several levels of
voltage, makes much more sense for supplying homes.

Damn. You mean, the power companies actually know WTF they're
doing ? Better even than the home-moaners they supply unlimited power
to 24 / 7 ????

**** ......




DC is sometimes used to transmit large amount of power long
distances.

Dave

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