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Tidal Power a Reality
updog writes "Here's an interesting story about a city in Norway using an underwater
turbine to generate electricity. It doesn't produce much power (300kW) but maybe it'll pave the way for these types of power plants. Maybe one under the Golden Gate someday??"
For those of you that don't know, this is something that author Marshall T. Savage proposed in his "Millenium Project", a book in which he set out a plan for how human beings can colonize the universe. Though I think he's far-fetched, the plan to build world-wide floating cities on top of hydrolical power-generating hexagons is feasible.
Check out information on the Millenial Project here or here.
This also brings me to the interesting Free State project, mentioned on Libertarian Candidate Rachel Mill's Homepage which links to The Free State Project. Interestingly, Rachel Mills decided to raise money for her run for office by selling pushup calendars of the female Libertarian candidates. Yep, Libertarians stand up for your rights and (some of them) do it while looking good too. A much better way to raise money than what the corrupt Democrats and Republicans do, which is by accepting tacit bribes from special interest groups.
social sciences can never use experience to verify their statemen
What kind of environmental concerns will be raised about this? I remember the project in Canada or whatever (name slips me right now, some big bay) that was being considered for damming to produce tidal power. However, because of the amount of water involved, it would change water levels all over the world.
Um, no.
The tide is actually a huge double-lobed bulge around the whole planet. To grossly simplify, two quarters of the planet have higher than normal water levels, and the other two have lower than normal.
Even if you built dams around all continents, the amount of water you'd trap would be about 0.1% of the surface area of the ocean, for a sea level change of one thousandth the height of the _dam_ (not the ocean). This is truly miniscule.
The real problem with dams is that when you build one, you flood a large region of land behind it. For areas that wouldn't normally be flooded (e.g. with hydroelectric projects), this causes environmental upset, and leaches all sorts of crud out of the rocks and soil far faster than rain leaching would (so you get a large spike in, say, mercury levels for a few years). This is unpopular.
Tidal areas are already flooded regularly, so the effects are far less drastic there. All you end up doing is making it very difficult for marine creatures to reach the shore (bad if you built in something like a turtle breeding ground), and change with the timing of the tide cycle (you need to drain the dam when the ocean is near the low mark and fill it when it's near the high mark to generate power, meaning a much more abrubt change in water level for the beach).
That would be the Bay of Fundy, IIRC. It has the largest tides in the world. I'm about to head off to bed, otherwise I'd look up some numbers for ya.
From an Aussie research report commissioned by Murdoch Universoty
"There are currently two commercial scale barrages in operation around the world: a 240 MW bulb turbine at La Rance, Brittany, France and a 16 MW plant at Annapolis Royal, Nova Scotia, Canada. Several other tidal power stations are being considered, including the Severn project in England"
lounge around on the blue couch
Systems that extract power from wave energy as opposed to tidal energy may be a little less problematic and a lot cheaper to build, albeit also on a smaller scale. The basic idea is to find a waterfront cliff and drill a hole straight down to about 10 feet below the water level, then turn and drill until you encounter ocean. The result is a tunnel with a column of water in it that moves up and down a dozen times a minute or, pushing a fair amount of water and air. Put a turbine in that tunnel in either medium, and you've got power.
Here is a diagram of such a design that uses a prefabricated tunnel rather than drilling. Google will turn up quite a bit about various designs and research.
All crackpots of course. Every good SUV-drivin' Amer'kin knows thar ain't no energy sources other than oil!
Only $13.4 million and it will power "perhaps 1000 homes". Wow, that's only $13,400 per home... couldn't they buy electricity from the grid for a lot longer than the expected working life of machinery on the ocean for a lot less money? Would you shell out $13,400 now for free electricity for the next 10 year? Or would you be better off putting the $13,400 into a CD and using the interest to pay your electic bill?
"Freedom means freedom for everybody" -- Dick Cheney
A better strat for that is to pre-design the landscape so the outer edge of the entire map is a 1 tile wide waterfall, then build hydroelectric power on it. You can increment in small doses ($400/unit if I reall) and they never expire over time!
Not sure if this is part of the project you're refering to, but Nova Scotia Power uses the tides of the Bay of Fundy to generate power... page also gives a BRIEF overview of how tidal power works for those interested - but not THAT interested :)
Actually, It would.
Friction between the Earth and water, drags the tidal bulge a little bit ahead of the moon. This, in turn, cuases an unbalanced pull that slows the Earth's rotation and transfers angular momemtum to the Moon.
The result is that the moon moves about 3.8cm further form the Earth every year and the Earth's Day increases by about 1.5 ms per century.
Tidal power plants would increase this drag and slighty speed up this process, (very, very very slightly, not enough to make much of a noticealbe difference, but a difference none the same.)
In effect, tidal power plants derive their energy from the difference between the Earth's period of rotation and the Moon's orbital period. Pulling extra energy from this system slighty hastens the day when the Earth eternally shows only one face to the Moon.(Not enough to worry about, though)
When quoting figures for the cost of power generation, it's always discussed with respect to, in units of kW/hr. And this article states the cost very clearly -- 30 to 35 cents, or about three times typical for Norway.
How is this news? There is a 240MW tidal generator that has been in continuous commercial use in France since 1966.
It's the "Usine Maremotrice de la Rance" (tidal generator of the Rance river) near Saint-Malo in Brittany.
It has been in service for 36 years and is still the only industrial-scale tidal energy generator in the world. It is also the most visited industrial site in France (300,000 tourists annualy).
More info at http://membres.lycos.fr/larance/main1.html
Isn't it strange that the publisher of Penthouse (Bob Guccione) is the only celebrity to ever endorse nuclear fusion, which is the only viable solution we are ever going to have to our insatiable lust for energy?
Funding for nuclear fusion is scarce, probably due to energy companies' opposition to anything that could possibly mean free energy.
Actually, this is wrong on pretty much all counts.
Fusion reactors are very big, and very expensive. This is why funding for fusion projects tends to get cut when economic belts are tightened. This is also why fusion energy will never be free - your plant has yearly costs (maintenance, and the amortized cost of building the plant over a reasonable payback window). These costs are passed directly on to the consumer, in the form of a nonzero price for electricity. The same happens with things like hydroelectric and fission power - the cost of the fuel required is low (or zero, for hydroelectric). You're paying for the plant/dam.
Lastly, the fact that electricity never will be free (due to the cost of facilities for producing/distributing it) means that a) there will be no magic free-energy solution, and b) our lust for energy had damned well *better* be sated, because otherwise we'll be awfully disappointed when we find out there isn't a free (beer) supply.
Oh, and if anything, I'd expect the big fossil fuel companies to be the strongest _supporters_ of alternative power sources. They're on top of the market now, and as soon as fossil fuel supplies wane and prices go up (or taxes on fossil fuel emissions rise), they'll want to be right there ready to sell the alternatives.
The process for creating a fusion reactor has been mapped out since the 1970s -- however, it would require the equivalent of 7 fission reactors to start the reaction before it can sustain itself, and materials including a very large 3-foot thick shield of lithium.
Startup power isn't really an issue. The real problem is that producing fusion isn't as simple as building a big donut and watching it go. Fusion ignition is harder than anyone thought 30 years ago, and the engineering problems involved with building a useful fusion reactor are orders of magnitude harder that we'd thought as well. Progress is (slowly) being made, but it's going to be a while, and it's *not* going to be cheap.
In summary, I'd suggest doing a bit more reading about fusion and power generation in general before extolling it's virtues as a cure-all.
How about this?
Free Hans!
Some readers might not know that there is a successfully working tidal power facility in the Bay of Saint-Michel in France since 1966. Its output is 240MW.
I found some pictures on the web.
This sig is a true statement, but I cannot prove it.
These do not rotate any fast; which is also an trend in windmills.
Its more efficient this way.
The article mentions that "fish can swim around them without getting sliced up".
The IWC has banned all whaling. But Norway uses its right to set national limits. These limits follow the rules set by IWC.
.no gov
Propaganda from
[provoce]And, well, Norway has been an good guy in the class; eg we (!) and switzerland was responsible for putting Environmental Concerns above Free Trade concerns in the recent Johannesburg meetings. Guess what countries objected?[/provoce]
There is a perfect location, potentially generating 5000 MW (Sorry for the pdf) on the Minas Basin of the Bay of Fundy between Cape Split and Parsbarro. These are the highest tides in the world, up to 16 metres.The entrance to the basin is approximately 8km wide, and could be dammed relatively easily.
On flows "The currents exceed 8 knots (4m/s), and the flow in the deep, 5 km-wide channel on the north side of Cape Split equals the combined flow of all the streams and rivers of Earth (about 4 cubic kilometres per hour)."
Back to where I started, Environmental impact: There would be huge disruptions to the intertidal zone, where much of the life of the bay lives. Siltation would be a major problem. The Petticodiac river in Moncton, NB, was partly dammed by a causeway in the early 1960's. Since then, the river downstream from the causeway has filled in with mud as it no longer gets flushed twice a day, and no longer gets the full effect of the spring runoff. Many of the rivers running into the Bay of Fundy are muddy. Will that settle into the basin? There are no longer any Salmon going up the Petticodiac river, largely due to the causeway. What effect would a huge dam/causeway have?
Any power generation will have environmental effects. It comes down to a choice as to which effects we choose to live with.
Michael (working at a nuke plant on the other side of the bay)
As others have pointed out, the Fundy tidal power project has been on line for something like a decade, and it is quire large.
Using tidal power for mechanical energy has been around for centuries. Here in Boston we have three meter tides; at the time of the revolutionary war we had mills driven by impounding tidal water in the Back Bay. Eventually the bay became so noxious with sanitary and industrial wastes that it was landfilled to make the neighboerhood of the same name, which is the only part of Boston with streets in a regular grid layout.
Boston and the Bay of Fundy are part of a the same physical oceanographic system where the amplitude of tides are increased by resonance. There are similar places in southwest England and in Scandanavia with large tidal amplitudes. I'm sure that many places with a tidal amplitude of two or three meters or more have a history of tidal mills.
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Seems your figure might be out by 3 or 4 orders of magnitude.