Slashdot Mirror
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??"
Please not to disturb great sleeping Cthulhu, I like human race to exist!
graspee
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. Obviously, this does not involve a dam, but wouldn't the turbine harm aquatic life, and how would the turbines disrupt normal sediment flow?
I'm the Devil the Windows users warned you about.
Oh sure...all those ships running into the turbines will give it extra spin. Free power, hoozah!
---- El diablo esta en mis pantalones! Mire, mire!
Everyone knows that coal and dams are the only way to go. All the green enegy sources are junk science. Because I sit around all day programming a computer I know everything about anything and I know this wont work.
Great! Admiral Kirk and crew grab two whales (and baby) to save the planet, they release them .. and the whales get chewed to sushi by the turbines. Probe shakes planet to bits shouting "Hello whales, wakey-wakey!" Ferengi sell souvenir Earth rocks. Profit!
But seriously, there's a lot of power in tides. Nice to see someone actually trying it out.
One line blog. I hear that they're called Twitters now.
but wouldn't the turbine harm aquatic life, and how would the turbines disrupt normal sediment flow?
Harm? don't think about that, just think how much extra energy is generated when fishies slam into the fan blades that drive the turbine.
"Not knowing when the dawn will come, I open every door." - Emily Dickinson
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
Tidal harness: increases energy production of this square by +2. Built by sea formers (*-1-4), 8 turns.
The thermal borehole is the one I'd really like to see in action, though. 6 energy and 6 minerals is a lot, and could really cut down on our dependency on oil.
Err, yeah...
I hereby place the above post in the public domain.
Here's one web page on the subject.
Anyway the tidal power finally line is a bit inappropriate.
combine the money and the political will into orbital solar
;) - same as a nuclear plant. Unfortunatly the cost per kWh is arround 2 - 2.5 times that of a nuclear plant, at the moment.
Ever played sim city 2000? Ever built a microwave power station? Ever had the beam slice through your airport and into a commericial zone?
OK, a little extreme. In reality the beam would be no more powerful then a cell phone.
I have read that Japan plans to launch one in the next 40 years. It will be capable of producing 1GW (although the article says 1GW per second
In 40 years? Who knows.
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).
I'm not sure why this is even a big deal. As the article states there are bigger and better tidal power stations. The La Rance power station in France has almost 8 times the capacity and is 40 years old.
Nothing earth shattering that I can see.
Slashdot comments can be accurate, highly modded, or posted quickly. Pick two.
1. Build tidal power plants, sapping angular momentum from the earth.
2. Days lengthen.
3. Everyone has to work 15 hour shifts (8 in France)
4. ???
5. Profit!
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!
Scandinavia will get a rather cold climate.
Err, dude, if you think scandanavia's not cold, I dont want to know where you live!
300 kWh may not be much on its own, but it may be better in the long run to rely on many smaller forms of energy production than a few large, heavily centralized systems that rely on actively polluting fuel (ie, coal, oil, gas, nuclear). A combination of wind turbines, solar arrays, and hydroelectric generators could be enough to take much of the load away from large fossil/nuclear plants, thus reducing the amount of fuel those facilities need to use.
I have this notion in the back of my head of new homes, and many older homes, being upgraded to include some small form of power generation - a solar array, or more likely a small wind turbine, to supply at least a bit of the home's own needs. Since you can still have a grid power system, homes can supplement each other, cutting part of the grid wouldn't necessarily cut all the power.
The expense would be horrid until these devices became more common, and energy companies could make up for losses in pure energy sales by providing maintanence and installation packages - that is, if you're the kind of capitalist that looks for these kind of opportunities.
Think of it as having a network where, instead of one big central server trying to handle everyone's programs and data, each host can handle most of its own data and processing, and the server's just there for the things that the hosts can't handle on their own:)
Opinions and nitpicks about this greatly appreciated...
Someday, you're going to die. Get over it.
and place mini turbines in all the toilets of the world and let the coriolus effect do the work for us? Energy flushes. Just think, in Australia they'd have the poles reversed!
OK. Now the moaning. The big problem is that people are always thinking in terms of "free" energy at the time of the electricity generation, instead of the Total Cost of Ownership, which includes the construction of the thing. Others have pointed this out, but I wanted to focus on the fallacy of romanticizing electricity generation with free fuel.
The second thing is that with this, the bulk of whatever environmental damage occurs will be largely invisible. Still it might be very limited.
Again, let me say that I am not against this project. I hope that this sort of thing leads to better technologies that are eco{nomically,logically} rational. We shouldn't expect a new thing to reach that at such an early trial. But again, I wish that people wouldn't romantize electricy generation based on "free" fuel sources.
Prime numbers are exactly what Alan Greenspan says they are -S. Minsky
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
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)
So, tidal power is really just harnessing the moon's gravitational pull on the oceans.
But, doesn't conservation of energy suggest that "we can't get something for nothing"?
By taking power away from the moon's orbit, aren't we just accelerating the decay of that orbit?
Sure, we've got the power now, but what good will it be when the moon comes crashing down to KILL US ALL!
*runs and hides*
Oh no!
They are taking power from the tides? The tides are generated from the gravitational pull of the moon. Taking power from it reduces the orbit of the moon, inevitably making it crash into the earth. Doom Doom Panic Panic.
I wonder how many exawatt-years that would be until it gets that far though...
--- Hindsight is 20/20, but walking backwards is not the answer.
Glad to see us Americans aren't the only dummies in the World.
In order to generate a kilowatt hour it would be necessary to
displace33000 cubic ft at %100 eff. assuming a tidal effect of
1 ft per hour. 1000 watts divided by a hrspwr [776 foot-lbs.]
times 550 times 60.. It would require a tidal pool 10 times
larger than the town it was designed to power just to supply
a minimum power per unit..
.
A system infinitely more effective is the "Wave Rocker"..
which has been going nowhere in the decades since its
inception. There are two types;
1) Tethered to the sea floor, as the waves come in, a float
rises & sinks with each wave. The tether cable turns a generator
as the float moves up & down.Its as though one ties a boat to a
pier, when the wave hits the boat it will snap the line if it has no give.
2) a boat whose length is eqal to 1/2 wavelength of the waves.
As the boat rocks in the surf, a bowling ball rolling around on the
deck pulls a lanyard wraped around the generator shaft.
.
Oilmen will tell you the floats collect barnacles & its costly
maintaining them. Anti barnicle paints containing capsicum
[chilli peppers] keep the little suckers at bay however.
.
Speaking of oil interests, how the hell the republicans could take
any seats in congress after Dubyah blew 10 terabucks in
the stockmarket I'll never know. He blew 600 million dollars of
investor money just trying to screw Martha Stewart,[ can't say
he's a cheap date but it wasn't his money.] They want Martha to
roll over on that Cancer doctorWelasec[?] because cancer
protects oil profits from nuclear power.
Enron is the Vampire of the stock community, the only way it can
be killed is by the government stopping trading on this stock.
It owns immensely profitable pipelines that replace revenue as
quickly as they can gamble the money away. If any of those
gambles were allowed to come in it would have doubled the
stock value. Enron deliberately created thousands of jobs
which were all trashed by Dubyah when he demanded Enron
cease functioning.
.
He blames the CEOs who have created America's wealth
& cites $100 million dollar bonuses. Personally if I were a CEO
& I brought in a billion dollars in new business a %10 bonus
wouldn't be excesive, it would be mandatory. Never having
worked a day in his life since the Skull & Bones made him
a "made Man"; being reimbursed for ones labors in a country
where life is measured in dollars doesn't mean anything to him
SPQR
While solar energy is a very promising option, there are a couple of catches that make it less ideal than advertised:
If your beam intensity is less than, say, the average intensity of sunlight, you might as well build photovoltaics or a solar heat engine on the ground, and save the cost of a satellite and receiving station. If your beam intensity is large enough to be useful (many times the intensity of sunlight), then it will cook birds that fly through it, muck royally with local weather (maybe even to the point of starting a local hurricane), and so forth. While these drawbacks aren't catastrophic, they have to be planned for.
There is no danger of the beam wandering and frying the landscape. It's generated by a host of phase-locked emitters - synced to a transmitter in the middle of the receiving patch. No transmitter to sync to, and the emitters on random phases send energy in all directions, and most of it would have a hard time hitting *earth*, much less your backyard.
Not horribly short, but you're going to have to amortize the cost of the satellite over a decade or two before something wears out or micrometeorites turn your panels/mirrors into confetti. A solar power satellite costs a _lot_ to lift, and power is cheap. My own back-of-the-envelope calculations suggest it costing 10 times more to lift than would be generated from electricity sales over a decade even with very favourable assumptions (100 W wall-plug output per kg of satellite, $10,000/kg to build _and_ launch, $0.10/kw*hr sale price of the electricity).
In summary, solar power will need several technological breakthroughs (or an order of magnitude increase in terrestrial power cost) before being competitive.
The breakthroughs are on the horizon, though. High-efficiency photovoltaic cells are coming on to the market, and thin-film cells can already be bought over the counter. Combine this with aluminized mylar concentrating mirrors, and you might have a satellite cheap enough to lift.
My money's still on fusion, though.
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.
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.
I remember crashing comets into Mars in SimEarth too:-).
But the proposals for satellite solar power involve wide, low power beams, not enough per square meter to cause a fire or even burn the skin.
The beam, with many times the energy per square meter than unamplified sunlight, hits a large photovoltaic receiver.
Hanging out under the beam would not be good for you, but it would not be instantly fatal, either, and as another poster pointed out, a simple fix would be to turn off the transmitter if the ground station was not receiving the beam.
One can point out greater dangers involved in hangliding around windmills or diving near tidal generators: the best rule is 'don't do that' (or as Ogg said to Mog: fire is hurts!), but like the others, & unlike nuclear & fossil, no toxic exhaust or poisonous waste is made.
As far as a rogue power taking over a beam station, simply staying indoors would be a decent protection until anti-satellite weapons took out the very large target.
More: The World Needs Energy from Space
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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