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!
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!
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*
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.