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Scotland Builds Power Farms of the Future Under the Sea
HughPickens.com writes "The Pentland Firth is a raw, stormy sound between the Scottish mainland and the Orkney Islands, known for some of the world's fastest flowing marine waters. Daily tides here reach 11 miles per hour, and can go as high as 18 – a breakneck current that's the reason people are describing Scotland as the Saudi Arabia of tidal power. Now Megan Garber reports in The Atlantic that a new tidal power plant, to be installed off the Scottish coast aims to make the Scotland a world leader for turning sea flow into electricity. Underwater windmills, the BBC notes, have the benefit of invisibility—a common objection to wind turbines being how unsightly they are to human eyes. Undersea turbines also benefit from the fact that tides are predictable in ways that winds are not: You know how much power you're generating, basically, on any given day. The tidal currents are also completely carbon-free and since sea water is 832 times denser than air, a 5 knot ocean current has more kinetic energy than a 350 km/h wind.
MeyGen will face a challenge in that work: The turbines are incredibly difficult to install. The Pentland Firth is a harsh environment to begin with; complicating matters is the fact that the turbines can be installed only at the deepest of ocean depths so as not to disrupt the paths of ships on the surface. They also need to be installed in bays or headlands, where tidal flows are at their most intense. It is an unbelievably harsh environment in which to build anything, let alone manage a vast fleet of tidal machines beneath the waves. If each Hammerfest machine delivers its advertised 1MW of power, then you need 1,000 of them to hope to match the output of a typical gas or coal-fired power station. "The real aim," says Keith Anderson, "is to establish the predictability which you get with tidal power, and to feed that into the energy mix which includes the less predictable sources like wind or wave. The whole point of this device is to test that it can produce power, and we believe it can, and to show it's robust and can be maintained."
MeyGen will face a challenge in that work: The turbines are incredibly difficult to install. The Pentland Firth is a harsh environment to begin with; complicating matters is the fact that the turbines can be installed only at the deepest of ocean depths so as not to disrupt the paths of ships on the surface. They also need to be installed in bays or headlands, where tidal flows are at their most intense. It is an unbelievably harsh environment in which to build anything, let alone manage a vast fleet of tidal machines beneath the waves. If each Hammerfest machine delivers its advertised 1MW of power, then you need 1,000 of them to hope to match the output of a typical gas or coal-fired power station. "The real aim," says Keith Anderson, "is to establish the predictability which you get with tidal power, and to feed that into the energy mix which includes the less predictable sources like wind or wave. The whole point of this device is to test that it can produce power, and we believe it can, and to show it's robust and can be maintained."
Any underwater installation will face the same challenges as Tidal power, that is what to do about the biologicals. The ocean is teaming with life and it will literally grow on anything. What do you do when the entire underwater "windmill" is covered in barnacles? Every underwater generation scheme is toasted by the life problem. None of them are tolerant of all the sea life that will grow on and around the facility.
Bah.
The real danger is these generators will extract all the energy from the tides and the Moon will crash into the Earth.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
A typical (500 megawatt) coal plant burns 1.4 million tons of coal each year. As of 2012, there are 572 operational coal plants in the U.S. with an average capacity of 547 megawatts.
http://www.ucsusa.org/clean_energy/coalvswind/c01.html#.VFe77y0wJIo
I don't know where the poster got their numbers from, but an average coal plant is around 500 megawatts not 1000. This would imply that you only need 500 of the hammerfest machines to equal a powerplant. They should probably be more careful in the future to use accurate data.
These turbines will kill all the fishies!
But, this is the power source "of the future". So, as long as the fish are in the present, they are safe.
That would be a neat trick...
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Actually, we need more of these so that the Moon wouldn't fly away! Won't someone think of the eclipses?
Ezekiel 23:20
And that's why ocean going super-tankers where never possible.(sarc'). Doesn't stop the Thames Barrier and Dams/hydro power across the world does it.
How about: Clean them off.
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Could you please inform the engineers that the North Sea is full of salt water? Armed with that piece of information that I'm sure they don't have, they can take that into consideration when designing this.
The Bay of Fundy has the most powerful tides in the world. "The estimated potential of the Fundy region alone is upwards of 60,000 megawatts of energy, of which up to 2,500 megawatts may be safely extracted."
Nova Scotia had a trail running in Nov. 2009 with OpenHydro and they ended up having to remove their turbine when, "20 days later, all 12 turbine rotor blades were destroyed by tidal flows that were two and a half times stronger than for what the turbine was designed."
http://www.cbc.ca/news/canada/...
Dams.
I realize some people like to curse dams, but still....
"I do not agree with what you say, but I will defend to the death your right to say it"
re: "since sea water is 832 times denser than air, a 5 knot ocean current has more kinetic energy than a 350 km/h wind"
Kinetic energy is an integration of the linear mv dv so equals 1/2mv^2 (whereas momentum is the simple product mv.)
So let's set the mass of a volume of wind at 1 and the mass of the same volume of sea water at 832 units.
The kinetic energy of the wind @ 350km/h = 1/2 * 1 * 350^2 = 61,250 units
The kinetic energy of the water @ 5 knots = 1/2 * 832 * (5 * 1.852)^2 = 35,671 units (1 knot = 1.852 km/hr)
-- Insert witty one-liner here. --
The ocean is teaming with life and it will literally grow on anything. What do you do when the entire underwater "windmill" is covered in barnacles? Every underwater generation scheme is toasted by the life problem.
Cover every bit of metal with an insulating coating, then print, deposit, or laminate gold or platinum electrodes on the surfaces. Connect 'odd' electrodes in one branch of a circuit, 'even' electrodes in another, than apply an alternating voltage between them. The seawater completes the circuit. Unless a life form lands on the metal - then IT completes the circuit. I suspect most life forms will not like a continuous alternating current passing through them, and will 'move to greener pastures". Overall generating efficiency will be reduced, but probably not as much as it would be by barnacles, etc.
I'm not a marine biologist and I don't know if this would work - just tossing the idea out there.
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Hard to build? Just build it somewhere else, tie some cement blocks to it, and heave it overboard! See, this is why I should be running everything.
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So how do you clean them? Do you send divers down several hundred feet to hand scrape a moving blade? Do you haul them to the surface? Do you haul them to dry dock like they do ships every 10 years?
Ships constantly scrape while at sea and are typically brought into dry dock every 10 years for a thorough cleaning with high pressure / high temperature cleaning. This isn't a ship, it's a stationary bit of metal underwater in some of the coldest water on the planet. It's not going to be spinning fast enough to puree living mater like a ships propeller and they get fouled and have to be cleaned by hand all the time.
Everything in water ends up covered in living matter. This isn't a problem for stationary non-moving/non-mechanical objects. It is a serious problem for anything mechanical that for example needs to spin freely. Every tidal or current generating scheme requires moving parts under water and that's a problem for anything that isn't operating at puree speed.
Oh yes they did! Anyone who tries to design an energy technology not based on coal or oil is clearly an evil motherfucker out to steal taxpayers' money! We should just fucking kill all the scientists and engineers who aren't working on coal, oil, and maybe nuclear, because after all, those are the only options that should ever be fucking considered. Kill scientists. Kill all of them!
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Uh, about that, the Rance tidal plant in France has operated for 40 years with nothing but sacrificial anode protection and it looks pretty good to me (see page 22).
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