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??"
Another reason to move our other 2 moons nearer--more tides, more electricity!
Then profit!
Cover your eyes and click this link!
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!
it's too bad all these little clean energy projects can't somehow pool their resources into building a few orbital solar satellites.
Tidal power will no doubt make sense in some areas, esp. where political or cultural factors make the increased costs (over fossil or nuclear) palatable & the local coastal conditions are right.
But it seems a better long term solution would be to combine the money and the political will into orbital solar, which has the potential to be cheaper than fossil, cleaner than tidal/wind/ground based solar, etc., and reach just about everywhere on the planet with the same basic technology.
I still wonder why we don't stick a bunch of generators in waterfall streams. The force of a water fall is much more than a normal incoming tide.
"Not knowing when the dawn will come, I open every door." - Emily Dickinson
I guess it's a good idea, but what kind of effect would we get if we start putting huge turbines in
the oceans that affects the currents? E.g. Mess with the Gulf stream, and Scandinavia will get a
rather cold climate.
minatures in toilets!
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.
What kind of environmental concerns will be raised about this? I remember the proposed project in Canada at the Bay of Fundy 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.
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.
Them west coast Canadians have been been doing this for a while now...
----------------------------
Esobofh - Currently drinking fresh mango juice.
...maybe it'll pave the way for these types of power plants. Maybe one under the Golden Gate someday?
All right, irregardless of the fact that placing a turbine under the Golden Gate bridge would be a hazard to shipping, it would give off enough power to, what, light up Pier 39? BFD.
If you take a look at the article, it says:
<I>The biggest tidal power plant in the world is a barrage across the La Rance river in northern France, in place since the 1960s. It has a 240-megawatt capacity, but Electricite de France has no plans to build new ones.
Canada's Bay of Fundy in Nova Scotia has the highest tides in the world, at about 39 feet. Nova Scotia Power's 20 megawatt plant at Annapolis Royal, built in 1984, is the only one in North America, but the company is now focusing more on wind. "There are ecological objections to building more tidal plants along the coast," said Margaret Murphy, spokeswoman for Nova Scotia Power. </I>
What does that tell you? That this new station is bigger than France's entry by !60! Megawatts. And that where the biggest tides are, they decided to go into windpower instead. Why? Let me repeat:
<I>"There are ecological objections to building more tidal plants along the coast," </I>
Before you go wishful thinking, read the article.
I guess these are for personal use.
The most interesting part about most renewable energies is, once the infrastructure is implemented, how passive energy production becomes. Solar panels just sit there and take energy that would be absorbed into the ground or reflect back to space. Wind and tidal power use two of the most fundamental components of our planets existence as we know it. Maybe geothermal power would be another to consider, or tectonic power.
Either way, what seems a bit ironic about how these energies are collected is how inefficient the collection process actually is. In fact how inefficient we deliberately aim to make it. We use such a small part of an enormous source of energy that it has virtually no affect on the environment. No one every argues that solar panels are going to take up all the sun's warmth and freeze our planet. Squeezing every ounce of energy sources has been the pitfall of almost all previous endeavours. Dams destroy river ecosystems. Coal and oil pollute beyond comprehension.
PS. I'd still rather have nuclear power than oil power.
sig
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.
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. Creating a miniature star with potentially unlimited power -- it can generate as much power as it is fed water to spin turbines -- doesn't sound good to the multi-trillion dollar oil, gas, and coal cartels.
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.
Nuclear fusion could still be done more easily and cheaper than space-based energy projects.
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!
You answered your own question. The effect will be as negligable as the space probe/planet orbit.
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!
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.
but is anyone else getting the feeling that the whole project is based on poor planning?
The article mentions four or five better ways to generate power but this is how they're going to do it dammit!
Look, I'm all for green power. I like the idea, but it seems to me that the whole thing is in the shitter to start with. The conditions that make it good for power generation make it bad for maintenance. It's possibly the most expensive to implement with little to no extra gain over wind or solar. Where's the payoff?
In short, how is this better than umpteen other green power generation implementations with less start up costs, lower maintenance costs and fewer headaches?
People's desire to believe they are right is much stronger than their desire to be right.
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
science has been making waves.
-- james
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
Yes, I always knew Tide is the most powerful.
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You know damned well what happens: Scottie swims by in a (plus-sized) wetsuit and yells "Captain! There be whales here!!"
"It was a summer's tale: Just a boy, his Linux, and a head full of dreams..."
You're both incorrect.
The gravitational pull of the earth is the source of power.
The water generating the power travels niether through the river nor over the falls. The water is pulled by gravity through pipes called penstocks to the turbines.
134340: I am not a number. I am a free planet!
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*
The other main issue with tokamaks are their sheer size - the research ones are pretty damn big - but from what I have seen, the size requirements for one to power a city was to have been about the size of a large 50,000 seat stadium. I am not saying such a machine can't be built, but the capital costs to do so are pretty prohibitive...
Reason is the Path to God - Anon
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
Where it comes from is just pretense. Its all about obeying the law. The all powerful second law of thermodynamics, that is.
The source of power is the dispersal of coalesced energy. The Sun has a lot of it (most of it having coalesced so far as to become matter), so its chemical process is designed to disperse it quickly. This leads to the processes you describe, as our planet has been infected by this energy from the sun.
As if we didn't have things like "properties of matter" to overcome in our quest to disperse energy - we also have to deal with the stuff from the sun.
Obviously this technique is just another one to add to the list of things that aid us in our work - the work that humans are uniquely qualified to do and which sets us higher than all of the rest of the creatures on earth: waste energy.
Now if you'll excuse me, I somebody just turned off one of the lights in the house, so I gotta go turn it back on. Plus, either the air conditioner or the heater just shut off; I need to go figure out which and get that up and running again.
Mod me down and I will become more powerful than you can possibly imagine!
I saw someone mentioned this as a joke, about fish getting mangled.
When my aunt was in college they went just west of here into Minnesota to check out the environmental impact of a large windmill farm (interesting stuff, sitting in Minnesota, controlled in California, owned by Enron in Texas). There were large numbers of bats running into the blades. I dont remember what they did to curb this, although I think it involved increasing the rotational speed. Any way, bet the same effect will happen with these.
Bet thatll teach Flipper not to hang out near the shore.
Damn that's clever. It is, in fact, goatse. Normally, I don't trust AC's saying "It's goatse!" so I'm warning signed in. That's pretty damn good though. I caught it by reading the address when I hovered over, but you almost got me. If the url was a little more obscured, that would be totally inpenetrable.
Anybody know of a way to manualy enter a domain to block images from in Phoenix? Having to go there and right click the image to not have to see it again... it's like killing Hitler as a baby, only with gaping assholes. *shudder*
The turbine is driven by a water current, not a tide, so it's not "tidal power". Yes, the current is driven by the tide but it's still a current (the article calls it a "tidal current"). Tides are the vertical movement of water, current is the horizontal movement of water. I just thought you all might appreciate this chance to expand your nautical knowledge. :)
My tide and current book for San Francisco Bay says the average peak tide at the gate is about 4.5 knots, which if I did my math right is about 7.6 feet per second, a little less than the one in Oslo.
I think though that Norway has many fjords, which are rather long, where they can line up a lot of thise turbines one after the other. Whereas the 'Gate is a just a relatively short constriction. They plan to build 20 of these things in Oslo just to generate enough power for about 1000 homes. I don't think there's 20 good places for a turbine like this in the Bay, so I'm not sure it would be very practical for us. Dunno, but that's my idle speculation for the day. :)
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.
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.
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
Say you had two massive, extremely sturdy poles which were joined together with a hinge. Let's say the hing was really a generator, and that this generator had an extreme gear ratio such that it would take thousands of tonnes to move opposite ends of the poles closer together. You just wedge the poles into something really strong like a tide or a fault line, etc...
Could we not gain a lot of energy from this technique?
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.
Have they ever managed to keep the plasma torus stable enough in a tokamak to use it? From what I understood, this was one of the main problems with research tokamaks, which was preventing the project from going further.
I've heard varying stories as to what the limiting problems are with current reactors (and all are probably true). However, an interesting development re. turbulence was made relatively recently. A group installed sensors and correction magnets on a tokamak, and suppressed the small irregularities in the containment field that turbulence produced. The result was much better confinement.
I don't have a link handy, but it might even have been on Slashdot many months ago.
My personal suspicion is that better materials will provide a big boost. I'm drooling over what nanotubes will do for anything that involves strong magnetic fields - they're the next best thing to superconducting, and their tensile strength means you can run an extremely strong magnet without worrying about it tearing itself apart. Both high density and long confinement times are much easier to achieve with a stronger magnetic field.
How about this?
Free Hans!
Remember the tho main effects (in the VERY long run, of course, though they can be measured right now by atomic clocks) of tidal power plants
1. They slow the earth rotation (which is quite normal, since they oppose the movement of tides, therefore making the earth slightly more "coupled" to the moon). No kidding.
2. They move the moon slightly away from the earth (slowly, but every year) for the same reason. You can also deduce that by another way, which is the conservation of momentum in the couple earth-moon.
Those issues were raised in their time when France built its tidal power plan on La Rance, near the town of Saint-Malo. A lot of people said that "the consecutive slowdown of the earth could never be measured". It has been. And, of course, nothing will revert if the power plant is - or rather when it will be - later stopped.
This is of course not a concern for us, but over the course of mankind as a species, it is. It is clear that just for energetic reasons there is no reasonable hope for the whole 6 billion people of mankind to emigrate anywhere else, even if we had an idea of where that "anywhere else" could be. So let us be careful with these experiments.
I wonder if the La Rance power plant could be in the future bombed by a decision of the UN or the NATO, just because it represents a (very very very very very) long term ecological menace
This idea wouldn't be all unlike the underwater "jet engine" that the Red October had....
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.
This is different. The la Rance generator uses dams, and floods the turbines (Probably both on incoming and outgoing tides). This uses underwater "windmill" (tidemill?) to generate power. No dams needed.
J.
Why would the Norwiegians care about aquatic life? They've been violating international treaty on whaling for decades, along with Iceland and Japan.
Not that I'm usually a tree-hugger, but it strikes me as hypocritical that the Scandinavians come across as looking good for pursuing "alternative" energy, when in fact that pursuit is motivated by profit margin and a scarcity of fossil fuel.
We can neither love nor pity nor forgive. If you make a slip in handling us you die!
The one advantage that tidal power has over all other current sources of energy is that it is the only energy source that is guaranteed to be in that same location every day for the next few thousand years (okay, next few hundred million years, but I'm speaking in current human social terms), unless we blow up the moon into little bits (like they did in "The Time Machine").
Oil, coal, gas and uranium are in limited volumes at the sources we find them, and will be gone when those sources are used up.
Where it is windy today might turn into barely a breeze over years or decades depending on weather pattern changes.
The sunny place you put a solar panel today could change to mostly cloudy all year in a few years to decades also.
Only the tide is immune from all near term natural and man made changes (short of intentionally blocking waterways just to screw with the location of a tidal power plant).
If they can figure out ways to make this economical, it will be a much more stable energy source than all other earth based sources combined.
One other thing to consider is that the one constant bottleneck in all of these forms of energy (except for direct solar, not "boiling water" solar) is the turbine. Increase the efficiency of turbines and you can get more energy out of all the current power plants by doing retrofits. It seems like this should be the highest priority in energy research.
YES YES YES!
Build it, and run it, until we get rid of leap year!
-- Terry
Nobody is ever happy with power generation. No matter what you pick, there are always critcs:
--Coal/Oil/Natural Gas: Air pollution
--Nuclear: Nuclear waste
--Hydroelectric: Rivers need to be dammed
--Geothermal: Releases lots of sulfer and arsnic
--Solar: Not cost effective
--Wind turbines: Kills birds
--Tidal: We'll think of something
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".
http://www.edisonpowerprogramme.com/pz/din.htm There is a British station that uses water turbines and stores electricty taken from off the grid by pumping water up to a reservoir and then releases it at peak times by letting it flow back down, driving a turbine. I have always thought it was a pretty neat solution - did a project on it when I was a kid. I think the upper reservoir is a natural glacial lake and all they had to do was dig a few tunnels, install the pumps and line some stuff with concrete. I remember it as being pretty impressive when I visted it. Link doesn't give much information I'm afraid but has some basics and a couple of pictures.
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
losing "most of what you send" is less of a problem. In fact, the inexhaustible nature of the power + the lack of cost for real estate are just two of the advantages orbital solar has over earth based.
However, from my reading of the subject, most of the loss is actually in the conversion from AC/DC to microwave, so again, having an inexhaustible power source at the sending end makes this much less of a problem, & also suggesting that the sending end might try other methods than conversion to AC/DC. If you have links discussing loss during transmission, I'd be most interested.
In any event, research into wireless energy transmission is steadily improving in efficiency and making SPS more and more attractive (Bright Future for Solar Power Satellites.
Further, most of the 'green' power methods involve extracting only a fraction of the available power (windmills shut down in high winds, for instance, so I think my original point stands.
And it looks like fusion will need to use He3 to be efficient in the near term.
Long run, better forms of fusion may turn up, but it seems to me that if one assumes the tech. to make fusion efficient, one can also assume the tech to make SPS efficient, at which point why bother making your own little suns when you got a real big one for free?
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.
Seems like your already well over the cost of a comparable solar satellite before you even get the reaction started, much less finding enough He3 to keep it going, not to mention the NIMBY problem when you tell folks you just need to build 7 new nuke plants to get it going...
Shave the Whales!
Seriously, what happens if some sort of large mamalian marine animal walks (er, swims) into a tidal power generator?
And what effect does this have on coastal erosion (good or bad)?
Obviously it's going to have some environmental impact. I'd rather that we spend extra time analyzing it now then paying the price for it later.
The Right Reverend K. Reid Wightman,
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)
Read the article more closely. It isn't Oslo that is getting the generator, but Hammerfest. Just like most news sources, the place listed in the start of the article is not the place the article is about, but the origin of the story.
Though not Tidal Energy. There is a (1990 - used to be ?) a working 1.1MW/150kW oscillating water column power plant using Wave Energy near my home town in India. There seems to be some details here. It was a research project done by IIT, Madras. A lot of details, pictures etc. can be found here.
That's 100 million Norwegian Kroner (NOK), not $100 million... About $13 million.
Hydro power is SOLAR power. If it weren't for the sun, all the water in the world would be evenly distibuted all over (well, neglecting tides, which don't matter for this). There would be no potential difference. Solar energy heats up water, making it go up into the atmosphere until it cools off and falls to earth again, but at a higher level, creating a potential difference. Gravity doesn't add engergy to the system, the Sun does!
A slashdotter who didn't build his own computer is like a Jedi who didn't build his own lightsaber.
Just for sake of argument...
Assume for a moment that:
1: All power usage on Earth is converted to electricity.
2: The historic growth trend continues.
3: All of this growing electrical generation need comes from tidal energy.
What would the effect on the Moon's orbit be?
I know all three assumptions can be flawed, but they constitute something of a worst case. I'm not comfortable with the simple assumption that, "We can't possibly break this because it's too big." If this scenario still gives answers in the millions-of-years range I'd be comfortable. If the answer starts creeping down into the thousands-of-years range I'd be a little concerned. Nor do I propose at the moment a "criterion for failure", just that no large-scale shifts be taken on the "It's too big" assumption without some sort of test.
The living have better things to do than to continue hating the dead.
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.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
They'll probably setup a special tax for the construction of this thing.
They'll probably call this the "Slatibartfast tax".
Off-topic, of course - I just have one thing to say about this: http://www.zompist.com/libertos.html
Such a tide-power plant has been in operation since 1966 in France. (More links here, too).
Tidal power is usually very dispersed. So you need to collect it over a wide area. This can be done, but has been expensive. So much so, that people haven't usually bothered, even though various plans have been around since ?? since WWII? earlier?
If these folks have figured out a way to make it efficient, then kudos. But it seems a bit more probable that they just had a place where getting any other kind of power would be too expensive, and tidal turned out to be cheaper. Still, materials and techniques keep changing. At some point this may be the way to go. (And in some places, it already is.)
I think we've pushed this "anyone can grow up to be president" thing too far.
Evolution is a matter of "use it or lose it." Features cost resources, so if you can get by without them then you've got more resources available for other things. I'm sure you knew that, but it's okay if you forgot because you're so damn sexy.
My deviantArt site
http://www.energy.ca.gov/etsr/9704ETSR.PDF
a nce/reactors/diablo.html
Where'd you get those numbers from?
From the DoE website on energy generation, wind generation costs are about $.05, but only assuming constant 13mph winds. [1] Thats excluding the costs to build an energy storage plant to store energy for nights.[4] Its also excluding TCO, for example noise pollution, ugliness, bird-chopping, road building to put them up (and cutting down inconvenient nearby forests.) Its also excluding all the pollution from mining, refining, smelting, and manufacturing the equipment.
Wind is also small-scale. For example, all 13,000 bird-choppers in California combined generate half as much power as one of the two nuclear reactors in the Diablo Canyon Nuclear plant. [2][3] (and at that, they generate unreliable power.) For comparison, each nuclear reactor generates 1gw, or about 3000x as much power as the tidal station we're talking about.
Almost all renewable power suffers from this, its usually either intermittent, or of such low density that it cannot source any more than a trivial fraction of the 300MW we use.
Last I heard, the cost for coal or nuclear is $.03/kWh, including disposal costs[7]. Unfortunately, nuclear power is much more expensive due to kooks.[5]
As for global warming, check out [9] or [8], where nuclear energy contributes either the same or much less CO2 than wind or solar energy.
Now, where are your numbers coming from?
Convergence
[1] http://www.nrel.gov/wind/cost.html
[2] http://www.energy.ca.gov/wind/overview.html
[3] http://www.eia.doe.gov/cneaf/nuclear/page/at_a_gl
[4] http://www.awea.org/pubs/factsheets/Cost2001.PDF
Which certainly seems to follow your claim.. However, if you look at where the actual numbers come from, you see something different and unpleasant. [6]
[5] http://www.ecn.cz/temelin/diablo.htm
Where the discussion about Diablo Canyon was an environmental 'success', because they forced construction to take 10 years and cost TWELVE times as much to build.
At least decomissioning costs aren't ballooning from kooks.[8]
[6] http://www.energy.ca.gov/etsr/reportsu.html
Which isn't quite so rosy. Specifically, they don't deal at all with the costs of the energy storage infrastructure. Intermittent power is EXPENSIVE if it
has to be stored. The *baseline* storage cost is on the order of
$.15/kw*H
[7] http://www.uic.com.au/nip08.htm
[8] Vattenfall 1999, Vattenfall's life cycle studies of electricity, also energy data 2000.
It shows the following CO2 emissions in kg/MWh (approx): Hydro 3, wind 5.5, nuclear 6, solar PV 50, gas combined cycle 450, coal 980, gas turbines (as reserve, peak load) 1170.
[9] Kivisto A. 1995, Energy payback period & CO2 emissions in different power generation methods in Finland
Finland (all kg/MWh CO2): wind 14, nuclear (centrifuge) 10, nuclear (diffusion) 26, Solar PV 95, gas 472, and coal 894
Who needs fusion? Fission works now. Fission is cheap. Fission can supply energy for millions or billions of years.
2: The historic growth trend continues.
3: All of this growing electrical generation need comes from tidal energy.
You cannot usefully project the current growth trend very far. First, energy consumption in 2000 averaged 1.3e13W. Assume that energy consumption doubles every 50 years, which is a growth of around 1.4% a year. Then in 1000 years energy use is about a million (2^20) times as large, or 1.3e19W. The energy received by Earth from the Sun is around 2e17W. The temperature of the Earth would have to increase a lot in order to radiate all that waste heat away.
Now jump to just 10000 years, when energy consumption has increased 1.6E60 times to 2e79W. The Sun outputs somewhere around 4e26W. 5e46 new stars will have to be acquired.
Talking about millions of years just gets absurd. The historic trend will have to change.
Finally! A year of moderation! Ready for 2019?
Why in the world would you build a solar power sat from materials that are conventionally launched from Earth at $10,000 / kg?
Build them from lunar materials instead. The much shallower gravity well would bring your costs down to, at most, $100 / kg.
Plus the $1000,000/kg amortized cost of the lunar mining facility.
Mining of lunar material is only cost-effective if you expect to use millions of tonnes of it or more. Solar power satellites don't _need_ that much mass, especially now that thin-film photovoltaic cells are becoming practical.