First power station to harness moon opens

New Scientist ^ | 09/22/03 | Danny Penman

[bedolido]

The first commercial subsea power station to harness the tidal currents of the sea was hooked up to an electricity grid on Saturday.

The rise and fall of the sea, caused by the moon's gravitational tug on the Earth, could be generating electricity for hundreds of thousands of homes within five years if the new Norwegian power station proves successful.

The power station, which resembles an underwater windmill, began generating electricity for the town of Hammerfest. Although still largely a prototype, the generator is the first in the world to harness the power of the sea and be connected to an electricity grid.

The tidal mill produces 300-kilowatts of electricity - enough to power 30 Norwegian houses or 60-80 British homes. Its designers hope to begin mass producing the devices within two years.

"Within a year we will have learnt enough to build a second generation device, says Bjorn Bekken, project manager for Hammerfest Stroem, the company that built the device. "I hope to see underwater energy farms within five years."

Professor Ian Fells of the University of Newcastle, says that tidal power has "enormous potential" despite costing more than wind power, another renewable resource.

"There's still a lot of hard engineering required before the costs will come down but we are going to need all of the renewables and nuclear power we can get our hands on if we are going to meet our Kyoto commitments," he told New Scientist.

Near continuous source

The device harnesses the tidal energy of the sea in the same way windmills tap into the power of air currents. The generator consists of ten metre diameter blades which rotate as water passes over them. These in turn drive a generator to produce electricity. The whole mechanism is held aloft by a 20 metre steel column anchored to the seabed.

If the first generation device proves successful, the company envisages installing up to 20 tidal mills off the coast of Hammerfest. After that they hope to begin mass producing them for the international market.

Tidal mills have the potential to provide vast amounts of energy. The European Commission estimates the currents around the UK, for example, could produce 48-terrawatt hours of electricity per year. The Commission has identified 106 potential sites around Europe, 42 of them off the coast of the UK including the islands and lochs of western Scotland, the Orkney and Shetland Islands and the Channel Islands.

Tidal energy has one key advantage over other renewable forms of power - it has the potential to provide a near continuous source of power 24 hours a day. Wave, wind and solar power all fluctuate throughout the day. By contrast, the tide flows continuously in one direction for just over 12 hours before pausing briefly and then reversing.

This means that tidal power has the potential to make a significant contribution to the baseload - the minimum amount of electricity needed by a country and usually provided by coal and nuclear power plants.

Hammerfest Stroem, which is backed by the oil firm Statoil and the engineering company ABB, estimates that mass production will lower the cost of tidal power to that of wind which costs about 3-6 pence per unit.

Danny Penman

[Arthur McGowan]

Rather than 18,000,000 years, the figure, if all of mankind's energy needs were supplied by tidal generation stations, would probably be something like 0.003682 seconds.

[KellyAdmirer]

This has to affect the snail darters somehow....

[freeeee]

It's probably trying to get away from the second hand smoke.

That, and it heard Hillary might run for President.

[HEY4QDEMS]

I'm sure there is Nor way that you meant to say Norwegia.

[ClearCase_guy]

would probably be something like 0.003682 seconds.

Yes, but it still would mean WE'RE ALL GONNA DIE!

[bedolido]

Of course, the moon is already spiraling downward because Earth's tides are not "lossless." Tidal generators will not cause a catastrope that wouldn't otherwise have occurred; they'll just hasten the day of its arrival.

Great... now I gotta worry about moon-crashing into earth insurance.

[Lazamataz]

WE'RE ALL GONNA DIE!

No no no no. Font size 7, bold, centered, not in all caps, and four exclamation points. Like this:

We're all gonna die!!!!

[Argh]

HAHAHAHAHAHAHA...................

[biblewonk]

What we really need is lots more windmills.

[HEY4QDEMS]

Of course, the moon is already spiraling downward because Earth's tides are not "lossless." Tidal generators will not cause a catastrope that wouldn't otherwise have occurred; they'll just hasten the day of its arrival.

I read in a science article that the moon on average moves about 1 to 1.5 inches further away from it's mother Earth every year.
Not that it will be any less devastating as it is the moon's gravity that keeps the Earth in gyroscopic rotation.
Without the moon, the Earth would orbit the sun in a chaotic tumble.

[Starrgaizr]

Orbital mechanics isn't my thing, but won't the effect be to lock the moon into a geosyncronous orbit? Unless it is too big to remain stable that close to earth. I think we need to tax the Norwegians for accelerating the impending global catastrophe.

[Dan Evans]

Denmark went balls-to-the-wall with windmill power but now these bird blenders are being dismantled because they only make money if they are heavily subsidised. The only reason people are building these alternative energy projects is they hope to clean up on the Kyoto CO2 credits.


http://216.239.33.104/search?q=cache:T4Y--vaUuOkJ:www.wwindea.org/pdf/articles/NewEnergy_Denmark_2-2003.pdf+windmill+dismantled+power+sweden+OR+denmark+OR+norway&hl=en&ie=UTF-8

[js1138]

This will slow down the Moon, causing it to crash into Earth with devastating consequences for women and minorities.

Actually the moon is getting farther away due to tidal forces. Can't do the math myself, but I've been hearing this for a long time.

[Arthur McGowan]

Must have been from Canadia.

[secret garden]

But we like the moon! Juvenile humor warning.

[TomHarkinIsNotFromIowa]

You're quite right, the moon is moving away from the Earth at a rate of about 4 cm per year, however it's due to the action of tides here on Earth. The tides are caused by the effects of the Moon's gravity on the oceans and the Earth. The short explanation uses Newton's law of universal gravitation ( Two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. ). This tells us that the water in the oceans closest to the Moon has a greater force on it from the Moon, than the force on the Earth or on the water on the opposite side of the Earth. You get bulges of water on either side of the Earth which are the tides.

The Earth rotates about its axis much more rapidly than the Moon travels arround the Earth. Since the Earth is rotating faster it carries the bulges ahead with it so that the tide is always a little ahead of the Moon. Newton's law said that two bodies attract each other so the bulge is constantly pulling the Moon ahead in its orbit. The effect, the bulge is lifting the Moon into a higher orbit.

This will continue to happen as long as the Earth's rotation is greater that the Moon's revolution arround the Earth. The friction between the oceans and the Earth's surface is constantly slowing the rotation down by about .002 seconds per century. What that means is that many Moons from now, when the length of a day equals about 47 of our current days, the bulges will align directly below the Moon and the separation will cease.

Hope this helps.

Mike Francis

[Stirner]

"The moon is slowly moving away from the Earth, not towards it."

I think you're right, but disaster still looms. Taking part of the tidal energy out of the process will not cause the moon to crash into the earth, but will instead cause the earth to rotate ever more slowly until just one side faces the sun. Estimated time 50 billion years.

[TomHarkinIsNotFromIowa]

This came from the following link:

http://www.madsci.org/posts/archives/jul99/932468789.As.r.html

[RightWhale]

This will slow down the Moon, causing it to crash into Earth

It's too late. The moon has already achieved escape velocity. However, the earth's rotation will slow a little quicker.

[ConservativeStandUP]

Why not just have a nuclear powered undersea windmill? Then you could power thousands of homes.