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RE: [cdn-nucl-l] " Norway tries underwater 'windmills' "
the additional info and comments.
3,000-kWh number for the Ontario house means an average consumption rate
for February of (3000/28/24) = 4.5 kWe, somewhat higher than the 2.6 kWe
that the Norwegian house would get if all its energy came from the
watermills. The tide flows no faster in winter than in summer, so
without another source of heat, the annual-average daily energy
available is also the maximum for any given day (with some fluctuation
because some tides are higher than others).
30 Ontario houses with watermills alone, they would have to have an
annual capacity of 30x4.5x365x24 = 1.2E6 kWh, which is 39,000 kWh
per home per year. Actual annual consumption, of course, would be a
lot less than that (as you implicitly point out), since much of the
capacity would go unused, most of the year being warmer than February.
above leaves no reserve for a below-normal cold spell. In
practise, absent efficient energy storage, , watermills would only be
used in conjunction with other sources of power. Although their output is
more predictable than windmills', it does fluctuate between zero and
maximum with a period of 6.2 hours. As with wind power, it's not clear to
what extent the need for installed capacity of other types would be
reduced. For space heating, perhaps the power supplied to the
heaters could be synchronized with the tides, assuming heaters with high
In view of
its cost, periodic nature, and possible ecological consequences, the
technology does not seem promising for anything but very limited niche
Jaro Franta wrote:
Date: Sat, 27 Sep 2003 09:49:29 -0400
If one just divides
700,000 kWh by 30 homes, its 23,300 kWh per home per year.
That's very high.
Here in Canada, the average annual consumption per home (Ontario) is just
under 12,000 kWh.
(in the coldest month (February), a large electrically-heated home
consumes something like 3,000 kWh)
But as you point out, the price per installed kW is astronomical -- and
doesn't even cover (or at least there's no mention of it in the article)
electrical batteries for energy storage during periods when the tide is
turning around, thus there's no, or little, current.
One thing that I find
appealing in the concept though, is that the flow past the
"underwater windmill" is always in a predictable direction, so
you don't need to have a rotating cab on top of your tower and, even
better, you can brace the tower in the plane of high overturning moment,
instead of the omnidirectional resistance one must build into ordinary
But I'm not so convinced
of the harmlessness of such installations to cetaceans & other large
marine animals, as claimed in the article (I suppose the Norwegians have
a different perspective on this subject, since they're one of the last
countries in the world still practicing whale hunting...).
- -----Original Message-----
- From: email@example.com.McMaster.CA
Behalf Of George Stanford
- Sent: Friday, September 26, 2003 10:34 PM
- To: multiple cdn
- Cc: firstname.lastname@example.org; email@example.com
- Subject: Re: [cdn-nucl-l] " Norway tries underwater
The article mentions "700,000 kilowatt
hours of non-polluting
- energy a year, or enough to light and heat about 30
homes." If my
- arithmetic is correct, that's an average output 80 kW, or 2.6 kW
- per home. Is that enough for a house in a Norwegian
plant in the Kvalsund channel, which had cost about
- $11 million by Saturday's launch . . . " Again if my
- correct, that's $137,000 per average installed kWe. Compare
- some $600 for a gas-fired plant, and maybe $1500 - $2500 for
- a nuclear plant (or is my estimate for nuclear high?).
- At 04:35 PM 9/24/2003, Jaro Franta wrote:
- Date: Wed, 24 Sep 2003 17:35:20 -0400
- Something weird with the numbers in this article... (installed
- for one, seems very small, even assuming a low CF).
- ....but they sure don't mince words, when they state flatly that
- windmills, by contrast, are useless in calm weather and have to be
- withstand hurricane-force winds."
- Wonder what the maintenance list includes... cleaning barnacles off
- blades ?
- Norway tries underwater 'windmills'
- Tides turn blades, providing power to local