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??"
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.
How would the energy be sent back to earth? Do you remember SimCity2000 and microwave power plant? When the beam from the satellite got out of sync with the dish, fires started.
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.
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.
To the best of my knowledge, we would be taking the energy from the moon, since it is the primary source of tides.
Since the moon is slowly drifting away from the earth (again, to the best of my knowledge), we could take just enough energy from the moon to keep it from drifting away at all.
that that is is that that is not is not
Actually, this sort of thing already exists. As a matter of fact, my father uses a diesel generator in the winter that pumps energy back onto the grid. The power company has to give credit on our power bill for the power we put back into the system. It also gives off heat as a byproduct.
Seabed turbines, by contrast, are silent and invisible, and fish can swim around them without getting sliced up. But that doesn't mean they can't swim through them and get sliced up instead, does it? Somehow this sounds kinda like political talk to me... hmm
Very simple solution, at the ground station have a satelite transmitter that is powered by the received power. If the satelite can't get the signal from the ground station it quits transmitting, so no stray beams iradiating innocents.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
This is a concept that's been kicking around the renewable energy community for years...look into the Department of Energy's Zero Energy Buildings Initiatiative, or more recently, Amory Lovin's book "Small is Profitable." - detailing how TCO for photovoltaics and wind generation, once capital risk and grid ops&maint. is taken into account, are very, very competitive.
Maybe that's why they've both been growing at 25%+ over the last 5 years or so. A tiny percentage yet, but gaining momentum against sometimes fierce utility opposition. (And sometimes, with enthusiastic utility assistance.)
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
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.
That would be the Bay of Fundy, IIRC.
If they were to dam it before Saint John harbour (you'd have a hard time driving ships through a dam), the Bay of Fundy is 65 km across. That'd be one hell of a mega-project. It would make the Confederation Bridge look like a plastic model.
It has the largest tides in the world.
And the Saint John River is one of two in the world that reverses its flow every day.
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.
127.0.1 goatse.cx(or whatever)
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.
I guess you've never been to a regular (thermal) plant, using river or sea for cooling (as opposed to those towers). Man, you could feed a small village by the fish caught (and often smashed) in the screens in frony of the circulation pumps.
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....
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.
I saw the tidal plant in Annapolis Royal, Nova Scotia this past summer while vacationing with my girlfriend. It is a dam, but there is little impact to the environment caused by flooding.
As the artlicle mentions, the tidal differences in the Bay of Fundy are remarkable, 39 feet, and the dam only holds the high tide and takes power from it when as the tide draws out.
However, elsewhere in the bay there does seem to be a whole lot of sea-life that has adapted to the phenomena of the tides. There is seaweed that thrives although it spends a lot of time exposed to the sun, and their are a ton of these snails. I came back with a whole back of their shells.
With respect to fish, I didn't see any way for fish to move up or down past the dam. BTW, best vacation ever.
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.
0.1% of the surface area of the ocean is still huge area, probably far more than you could reasonably build a dam to contain. With respect to the volume of the ocean and dam would be the proverbian "drop".
, and fish can swim around them without getting sliced up.
But that doesn't mean they can't swim through them and get sliced up instead, does it?
I think you're confusing low head water turbines with aircraft engines. The turbine will probably be something like a Kaplan which has big wide blades and turns at quite low speeds. Fish tend to flow straight through (though it would be rather disorienting for them I'm sure)
What surprises me is that these things have been used for years - I'm sure I read about 5 or 6 different designs of tidal and wave based generators a good 10 years ago when I was interested in these things.
Disclaimer - I have a lot more experience with high speed/high head impulse turbines (my father still has an original 1896 pelton water wheel with 'patent pending' on its cast iron sides - we took it out of production about 6 years ago when we decided the bearings were going through too much oil, and the new peltons could get an extra 20% efficiency, especially with specially wound low-speed alternators rather than old DC motors and v-belts)
I'd like to see some of the more imaginative wave-power systems used though (think balloon on surface anchored to cable on seafloor with bi-directional pump and bigass spring)
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
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.
I remembered an interesting article in Wired about a kind of "energy internet" very similar to what you describe.