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

[dangus]

>>But we like the moon! Juvenile humor warning.

No butts. I'm glad.

[ArGee]

This tidal generator takes energy from the moon's orbital angular momentum; the energy thus generated will cause the moon to slowly lose "altitude" and spiral down to an inevitable collision with the Earth.

Since the total mass of the earth is not being changed, are you positing that the back-and-forth motion of the seas helps sustain the moon's orbit? Additionally, are you suggesting that the amount of resistance provided by these seamills would amount to any significant percentage of the amount of energy required to set the seas in motion?

I'm honestly curious.

Shalom.

[ArGee]

What we really need is lots more windmills.

Post two outside the Senate and you could power the entire grid east of the Mississippi.

Shalom.

[ArGee]

Isn't Norwegia right next to Swedeborgia?

Right, just south of Victorborgia.

Shalom.

[dangus]

>>I would also venture a guess that heating efficiency would have something to do with it.>>

Exactly, most people expend significant energy maintaining a large temperature gradient between their beers and their homes. Not so the Brits, who keep their houses so cold that their refrigerator simply functions as a padded cabinet.

[MineralMan]

Nonsense! Tidal generation plants have been in operation since the 1960's.

I quote:

"Tidal energy conversion systems extract energy from the changes in the level of ocean water during tidal cycles. A tidal energy conversion plant typically consists of a tidal basin created by a dam, a turbine and generator and a sluice gate to allow the tidal flow to enter or leave the tidal basin. Tidal energy using conventional hydro-electric technology has been demonstrated at La Rance Estuary in northwest France since 1962. The plant consists of twenty-four 10 MW turbine/generators operating on the maximum tidal amplitude of 14 metres."

Cite:

http://www.energy.qld.gov.au/electricity/infosite/elecgen3/rotation3_1/waterturbines/waterturb.htm

This is an example of poor reporting by someone who just read a press release and didn't even do a Google search. Try it, by searching for "tidal electric generators." I hate this stuff!

[MD_Willington_1976]

Temperature of the surrounding area, Most of the UK is somewhere near 50 North and the Autumn & Winter are not that bad. Norway, especially the farther north you go gets DARN COLD...As a result they use a lot of electrons to heat their homes during Autumn and Winter, especially in Nordkapp at 110 North Latitude. Although the Norwegians don't all seem to be bothered by the cold weather:

Five Day High Temperature Forecast: Nordkapp

Monday to Friday.

8°C/46.4°F

9°C/48.2°F

2°C/35.6°F

3°C/37.4°F

2°C/35.6°F

[HeadOn]

I think about a half dozen big windmills positioned just outside the Capitol Building could power the entire east coast, as long as Congress is in session...

[MineralMan]

Here's a huge tital generation project that's been working since 1984, link at bottom.


The Annapolis Tidal Generating Station was completed in 1984. It was a pilot project sponsored by the provincial and federal governments designed to explore the potential of harnessing energy from the sea.

Annapolis Tidal utilizes the sea water of the Bay of Fundy. Tides, which can sometimes reach 21 feet in height, rise and fall every 12 hours and 25 minutes in harmony with the gravitational forces of the Sun, the Earth, and the Moon.


Annapolis Tidal Generating Station
2003 Visitor Centre Hours
May 15 - Oct 15
Daily, 10:00 a.m. to 6:00 p.m.

This facility has the distinction of being the first and only modern tidal plant in North America. The station is located in Annapolis Royal by the Bay of Fundy, home of the world's highest tides. Twice a day, the tide comes in and out. Twice a day the turbine turns. Twice a day electricity is generated which is supplied to the provincial electric grid.

Annapolis uses the largest straflo turbine in the world to produce more than 30 million kilowatt hours per year - enough to power 4,000 homes.

http://power.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.nspower.ca%2FAboutUs%2FOurBusiness%2FPowerProduction%2FHowWeGeneratePower%2FTidalPower.html

[thulldud]

OK, I remember the concept now. The energy to boost the moon into higher orbit is supplied by the earth's rotation, which is slowing down. It is a simple transer of energy, not magic. So now some genius needs to answer the question -- will tapping the tidal energy increase or diminish this effect?

Offhand, I would expect that it would reduce the tidal effect on the moon, since you would be bleeding the energy pipeline like this:

Earth's angular momentum -> seawater bulge -> Moon

Earth's angular momentum -> turbine -> seawater bulge -> Moon

The tidal effect on Earth (slowing its rotation) would be much less affected. Earth would still be slowed by the tides, but less of that energy would be transmitted to the Moon because the tidal bulges can't rise as fast as before.

Of course, the difference probably would not be measurable by any instruments in existence today.

[3Lean]

Not to mention that the Senate, just like the tides, changes direction every 12 hours.

[Calvin Locke]

On the bright side, wouldn't it slow down the "theft" of rotational energy by the Moon?

Still, I'm voting for that asteroid in 800 years or so, long before the Red Giant process.

In any case, long after I shed this mortal coil.

[ArGee]

Not to mention that the Senate, just like the tides, changes direction every 12 hours.

So what you're saying then, scientifically speaking, is that we'd need another set of windmills outside of D.C. area bars to catch the backdraft?

Shalom.

[non-anonymous]

The tide involves more than just water - the entire planet distorts slightly. The Earth's rotation constantly sweeps the tidal bulge ahead of the point directly beneath the Moon. Since this bulge is closer to the Moon than the rest of the Earth, and is off-center, the Moon feels a gravitational tug which doesn't line up with the geographical center of the Earth. Since the Earth rotates in the same direction as the Moon orbits, the bulge leads the Moon, and the forward tug accelerates it and causes it to move further away. In addition, the Moon pulls disproportionately on this off-center bulge, slowing Earth's rotation.

[Willie Green]

Although the Norwegians don't all seem to be bothered by the cold weather:

You are a very, very cruel man for having posted that picture.

I don't know whether to thank-you or curse you.

[PsyOp]

But think of the fish! All those whirling turbines just waiting to turn them into sushi!

The first time some endangered marine mamel gets a boo-boo from one of these things it will be all over.

[non-anonymous]

Read my post #74.

Ideally, tides make the Earth look like an ellipse, with the major axis pointing directly at the moon. The Earth's rotation causes the material in the bulge to rotate away from this axis, and the tidal effect affects the non-bulge material moving into the axis. Therefore, you get a "standing wave" which is directly below and ahead of the moon, which exerts more force on the Moon because it is closer.

It's the internal friction and angular momentum of the material in the Earth which causes this lag. An all-water planet should have less lag than an all-rock one, simply because material can more easily flow into the bulge. By that analogy, if you restricted the movement of the water, it would be less "fluid", and increase the overall tidal lag, therefore increasing the overall effect.

A lot of orbital/rotational energy goes into internal heating of both Earth and Moon.

[Whispering Smith]

I do not believe this is the first tidal power plant. I read about and saw pictures of similar plants when I was in high school back in the '50's.

[WOSG]

It didnt but it should have .... the slimy greens woked hard to forbid letting nuclear power "count" as green technology, so their other favored solutions are used only.

[boris]

"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."

A 1000 megawatt prime power plant in the U.S. produces 1000x1000000x24*365 = 8,760,000,000,000 watt-hours per year or 8.76 terawatt hours. That is 8.76E12/300000 = 2920000 times as much energy. What does the 300-kilowatt plant cost? Compared to the cost of a standard generating plant?

" 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."

Notice the "could produce". At what cost? At what efficiency? Not stated, and for the obvious reasons.

--Boris