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Technology Science

World's Largest Wind Turbine 445

PeteJones writes "'Construction work on the REpower 5M was successfully completed last night with the installation of the rotor. Thus the main work on the prototype of the 5-megawatt, world's largest wind turbine has finally been completed.' The pictures are quite impressive. With 3 18-ton rotor blades pumping out 5 MW I wonder if my neighbours would mind one in my backyard?"
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World's Largest Wind Turbine

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  • Wind Requirement (Score:3, Interesting)

    by pmazer ( 813537 ) on Saturday October 02, 2004 @12:58PM (#10413755)
    How much wind does that thing require to spin?
    • Re:Wind Requirement (Score:3, Interesting)

      by trip11 ( 160832 ) *
      I belive I read that it will run with winds of between 3.5m/s and 25m/s. With a nominal wind of 13m/s. Convert to mph or your favorite units at will.
    • Re:Wind Requirement (Score:5, Interesting)

      by kentmartin ( 244833 ) * on Saturday October 02, 2004 @01:08PM (#10413835) Homepage
      Wind required to spin is probably very little, ie, it would have to be very nicely balanced, and, once you got it moving (remember there is a total of 54 tonnes of blades here!!!) the rotational momentum must be incredible.

      What would be interesting to know is, how much wind is needed to produce 5MW!? Someone feel like doing the physics to work out how much wind would be required to hit a disk 1/2rd of this size (roughly - aviation theory, it is why you feather dead props, windmilling a dead prop produces the drag of a disk about 1/2 it's size) of that size would be required (at 1013Hpa sea level of course) to produce 5MW at 100% efficiency.

      Also, if you want to see prettier pictures, I advise you to wait a couple of days, then come back and take another look - they have already changed them to smaller different ones in the "brace yourself Shiela, it is pissing slashdotters" frame of mind.
      • Re:Wind Requirement (Score:3, Interesting)

        by guamman ( 527778 )
        The webpage says it has to spin between 6.9 and 12.1 times a minute to generate 5 megawatts +/- 15%. I know this doesn't answer the required wind speed question, but it seems relavent.
      • Re:Wind Requirement (Score:3, Informative)

        by legirons ( 809082 )
        "Someone feel like doing the physics to work out.."

        "The guided tour [windpower.org] is written for people who want to know a lot about wind energy, short of becoming wind engineers."

        For anyone with a long list of questions they think will be best answered by posting them on slashdot, the windpower.org website has enough to keep you occupied for the rest of the evening.

        Power output calculations here [windpower.org] - remember it's statistical, so don't just assume constant wind speed and multiply it by the average weight of air
      • Re:Wind Requirement (Score:4, Interesting)

        by Martin Blank ( 154261 ) on Saturday October 02, 2004 @04:17PM (#10415261) Homepage Journal
        Well, I did some rough calculations, and given the area of the disc on the page (12,469 square meters) and using a rough density of dry air at sea level (1.25kg/m^3), a 13m-thick cylinder of air passing through the disc area at the named nominal 13m/s (in other words, one second of air) would have a KE of about 17MJ. This suggests about 17MW would be the theoretical 100% efficiency at that velocity, putting this a little under one-third efficiency, which would be about on par with what is usually expected.

        I think I got that right. Feel free to correct me. (Not like Slashdotters need permission for that, but I'm feeling polite this morning.)
    • I don't know... how many politicians do you have?
    • by imsabbel ( 611519 )
      Cut in speed for this model is 2.5 m/s. Cut out speed 25m/s.
  • It slices! It dices! It makes julienne fries!
    • by MouseR ( 3264 ) on Saturday October 02, 2004 @01:02PM (#10413793) Homepage
      Yeah... I bet the bird collector down at the bottom is quite large.
      • I'm not thinking that it actually gets up to food-processor speeds. Birds fly quick enough that unless they actually flew into a blade head on, they stand little chance of being hit (though a hit would probably be a kill, given the mass behind the blades ...)
  • by Anonymous Coward
    ...they could create a politician and run for public office. The amount of hot air produced would give it an insurmountable advantage.
  • Does this sort of über-large wind power machine generate more energy than it takes to create, install, and maintain it? I remember reading that the smaller machines required more energy over their lifetimes than they were able to generate.

    If that's becoming less true, I think this is a great thing. I worry a little about the environmental effects of "taking energy out of the wind", but I haven't read about anyone important who shares my worry, so it's probably unfounded.
    • by Lust ( 14189 )
      negligible energy withdrawn compared to total power of atmosphere. may as well worry about effect of high-rises on wind patterns. Far more important things to focus on...
    • by jeti ( 105266 ) on Saturday October 02, 2004 @01:06PM (#10413820) Homepage
      If that's becoming less true, I think this is a great thing. I worry a little about the environmental effects of "taking energy out of the wind", but I haven't read about anyone important who shares my worry, so it's probably unfounded.

      The whole of Europe was once covered with forests. Now most of it is covered by farmland and urban areas, which offer less resistence to wind. If anything, those windmills will bring back more "natural" conditions.
      • by Whyte ( 65556 ) on Saturday October 02, 2004 @01:44PM (#10414068)
        If anything, those windmills will bring back more "natural" conditions.

        Minus the part with whirling steel blades that regularly vivisect birds and flying mammals you mean?
        • by Cecil ( 37810 ) on Saturday October 02, 2004 @02:23PM (#10414340) Homepage
          It usually takes longer for this unscientific, unfounded idiocy to pop up on a wind turbine story, but here you are. Congratulations. People like you make it clear you have never seen a wind turbine, have no concept of environmental conservation, and are just parroting anti-wind lies invented by people vehemently opposed to reducing dependence on oil.

          BIG, SLOW MOVING BLADES DO NOT CHOP THINGS UP. PERIOD. The danger posed is extremely minimal. It's theoretically possible for a bird to run into one of the slim, slow-moving blades, and that would likely cause injury, just as if they had run into one of our fancy new all-glass-exterior skyscrapers. But more birds are killed every minute by deforestation and destruction of wetlands, than will be killed by this thing in its entire working lifetime.
    • by drwho ( 4190 ) on Saturday October 02, 2004 @01:09PM (#10413839) Homepage Journal
      Does this sort of über-large wind power machine generate more energy than it takes to create, install, and maintain it? I remember reading that the smaller machines required more energy over their lifetimes than they were able to generate.

      Sounds like typical anti-wind propaganda. Its funny, every time this argument is brought forth for wind or solar, someone says 'I just read it somewhere' - I have never seen hard figures to support such a critique of the economics of alternative energy. I am sure it could be done for a specific installation that was poorly design, or used outdated techniques (like those horrible inefficient copper photovoltaic cells).

      If that's becoming less true, I think this is a great thing. I worry a little about the environmental effects of "taking energy out of the wind", but I haven't read about anyone important who shares my worry, so it's probably unfounded.

      If only we could slow down some of those winds, I am sure a lot of people who just suffered from hurricanes would be rushing to install wind turbines! But no, the amount of wind taken by even the largest turbines is so infinitesmal as to not matter. It would be like fretting about contributing to global warming each time you farted, to worry about these machines causing environmental damage by calming a windy area.

      • Well, how about the IEEE Canadian Review magazine?

        The latest copy (number 48, page 24) states that it takes 2 to 4 years to recoup the electricity required to produce photovoltaic cells. Fortunately, they do on average last about 20 years, so you do get an 'energy gain'.

        You can safely assume that the same is true for wind power which is also a 'low energy density' device that will take a long time to pay itself off.

        • by angel'o'sphere ( 80593 ) on Saturday October 02, 2004 @01:58PM (#10414154) Journal
          And how long does it take until a coal plant has produced the amount of energy needed to build it? Or a nuclear plant? As a sidenote: I have read figures that building a nuclear plant produces more CO2 then it later saves during its energy production time (mining and enriching fuels, transportation of building materials, fuel and waste, storage of waste, security activities during transportation etc.)

          The original poster claimed/implied, the energy usage in production was that hughe that it never would pay off energy wise. Thats simply wrong. For solar cells its wrong since 20 years. I would guess for wind energy it was allways wrong, except if you had chosen an idiotic production process, e.g. very small wind mill made from aluminium.

          All ways of generating energy first eat a lot of energy in creating the power plant. Thats live, erm, such is our industry.

          • by dbIII ( 701233 )

            the energy usage in production was that hughe that it never would pay off energy wise. Thats simply wrong. For solar cells its wrong since 20 years.

            The energy calculation is simple.

            First you consider the cost of setting up a silicon zone refining plant and assume that microchips do not exist, so you can't use an existing plant. Then you consider the cost of mining the sand, and deoxidising the silica, which takes a lot of energy, and once again assume that it is not being done for any other purpose (like

      • Those damn lazy Dutch, spent all that energy building those windmills when for half the effort they could have strapped their asses to the grinding wheel and sweated out a few tonnes of grain.
    • Well, (Score:4, Informative)

      by autopr0n ( 534291 ) on Saturday October 02, 2004 @01:21PM (#10413936) Homepage Journal
      I know that for smaller windmills, say the 1-5kw models you can buy online would pay for themselves in saved electrical bill cost in about 5 years.

      And thats the cost to buy the thing. Meaning materials, employees, as well as power in production. I don't see how you can say the power required to make it would be more then the power generated. I mean, unless the manufacturer were getting power for free, which is pretty unlikely.

      Windmills are simpler then most other kinds of power plants too.

      Now, i've heard that solar cells have this problem, though.
    • The other solution is Kites - they require less power, and can be raised into the jetstream.

      The Kite is made to oscillate and the power pulses converted to rotational energy on the ground. (My Design)

      there are other more complicated Kite systems, but in terms of power out V. cost and enegy in - a kite is a self erecting tower, minimal risk to birds, an elegant almost artistic symbol for a city, and can scale nicely with multiple kits on a shared cable.

      However, Oddly, the energy delta may not matter.

    • Taking energy out of the wind? Someone's been reading too much of the Mars trilogy by Kim Stanley Robinson
    • by gnalle ( 125916 ) on Saturday October 02, 2004 @01:46PM (#10414078)
      The large windmills are effective because there is more wind at higher altitudes [windpower.org]. The windspeed v(z) as function of height z is given by

      v(z) = v0 ln(z/z0 )/ln(z1 /z0 )

      Here v0, z0 and z1 are constants. Here is a nice site [windpower.org] about windmill engineering.

      • So why not Kites.

        They can get up to higher windspeeds without all the hassle of a tower?

        • It's a thrilling idea, but it would costs a lot of money to produce a 10 km string, that is strong enough to hold the kite. (Basically the string has to be strong enough to be able to hang in one end). You have to compare this cost with the money that you can earn from the turbine.

          The present kite heigh record is 13,600 feet [kitelife.com], so we are still below the jet streams. The record kite is far too light to carry a turbine, but of course we could try to scale everything up :)

          Finally I think that there is an el

      • I would also like to pose the question of different wind currents at different altitudes as being a problem. With a big diameter (about 126m in this case) you are fighting yourself. You are actually moving faster than the wind would push at a lower altitude, presumably. I'm not even considering that the wind generally changes direction when you get higher, but I think that's actually much higher.

        With these premises, would you not think that there is one good optimum size of the blades, and you should pr
    • One problem with generating electricity (or running a car) with fossil fuels is that it puts net energy into the global atmosphere. (theremal differences cause air-flows, ie. wind) This is one of the few ways of taking that energy out again, so it can only be a good thing. Solar energy, use of waste-heat from industry, etc. have similar net benefits.

      When you use that energy to light your house or play music, most of it ends up as heat again anyway, feeding the system, but at least this way we are not gener
    • Just a link [slashdot.org] to a previous post on the possibility of reducing global warming by taking removing energy through wind turbines. Conclusions: it's not going to happen.
    • by Willard B. Trophy ( 620813 ) on Saturday October 02, 2004 @02:07PM (#10414225) Homepage Journal
      Reharding energy payback, the Danish Wind Energy association says: "Under normal wind conditions it takes between two and three months for a turbine to recover all of the energy involved". There's more information on their Energy Payback Period for Wind Turbines FAQ [windpower.org] page.

      As regards taking energy out of the wind, the atmosphere's about 11km high, and the wind profile goes up from zero at ground level to pretty fast up in the jetstream. A turbine's wake is mostly dissipated at about 8 turbine diameters downwind, too. So even a wind turbine of this size might only affect less than 1% of the total atmosphere's height, for less than a kilometre horizontally.

  • by Anonymous Coward
    It should get plenty of hot air to spin it,
  • They'd mind it a lot less when you told them it means free electricity for the whole block.
    • And even less when they actually get paid from profits created by running the things.

      http://www.baywind.co.uk/pages/Westmill2.h tm

    • Free, once you pay of the mortgage used to build the thing, and find some alternative method of acquiring spare parts for when it breaks ...
  • by wfmcwalter ( 124904 ) on Saturday October 02, 2004 @01:05PM (#10413809) Homepage
    A while ago (with a previous generation of wind turbine technology, for sure) someone built a particularly large wind turbine on one of the windier islands of Scotland's west coast, hoping to replace (or lessen) expensive shipments of fuel oil. Power production was fine, but the locals were driven to distraction by the noise the thing produced, particularly when the windspeed was high. I believe it produced a very loud "whump" every second or so, loud enough that no-one could sleep. I believe the conclusion to which the developers came was that very large turbines were prone to this problem.

    Still, that was a while ago (maybe a decade) so I'd imagine the developers of this new megaturbine will have engineered out the "whump" issue.
  • Uhm.. NO! (Score:4, Funny)

    by Anonymous Coward on Saturday October 02, 2004 @01:06PM (#10413815)
    With 3 18-ton rotor blades pumping out 5 MW I wonder if my neighbours would mind one in my backyard?

    This is Joe from down the street.
    Please.. just please, stay in your mother's basement, you creep.
  • If they can make it a bit smaller, it would make a wondeful vacuum cleaner! I mean, a REAL vacuum cleaner.
  • by demon_2k ( 586844 ) on Saturday October 02, 2004 @01:10PM (#10413847) Journal
    How big would a Wind Turbine have to be to power a house? Some people already have solar panels on their roofs, why not a small Wind Turbine?
    • The average house that has solar pannels on the roof produces something on the order of 10^4 watts. The problem for an off-grid is not generating the power, but storing it. Typically to have an off-grid system one would need a medium-sized shed full of batteries and intervters. However, if you are hooked into the grid you can sell your excess power back to the power company when you have a surplus and consume from the grid when you do not.
    • It wouldn't have to be very big. I saw some 20 years ago, but they tended to spin very fast, so it makes lots of noise and is more harmful for birds. The economies of scale also work against you.

      If you want to be off grid or just more eco-friendly, your best return on investment is in efficiency. CFL/LED lighting, passive solar heating, solar hot water heating... anything that avoids investing too much in PV modules and batteries is probably a good bet.

      There are more challenges for creative geeks in reduc
    • Some people already have solar panels on their roofs, why not a small Wind Turbine?

      In Holland, some farmers up north have big turbines which power their house. Excess power is sold to the powercompanies, and distributed to the main grid.

      If your backyard isn't big enough, just build a small one yourself [re-energy.ca]!

    • Over a decade ago someone put a goodly sized wind turbine up near their home (in Ohio, I think in Deerfield off of route 14). I'd estimate its height off the ground around 30 feet, and from the tip of one blade to the end of the other was probably around 15-20 feet.

      We would drive by this house a few times a month, and over the course of many years we never saw the windmill rotating once - the blades were always in the same position.

      We always assumed the gearing was wrong, or they were trying to push too
    • Not very big... (Score:5, Informative)

      by the_twisted_pair ( 741815 ) on Saturday October 02, 2004 @04:20PM (#10415285)
      ..but it depends where you are (local average wind speed, depends heavily on topography) and how much power you need.

      If you can find a way of levelling the load (e.g. batteries) with only moderate conservation you'd need the equivalent of a constant 1kW output, about 1.4 Hp. Power abstracted from a windmill follows the formula k*0.5*A*V^3, where A is the area of the blade disc, V the windspeed, and K is the fudge factor. There's a theoretical limit of about 59% efficiency, due principally to retaining enough momentum to carry the air on the downwind side away from an axial turbine.

      Anyway... say you have a mean wind speed locally of 10mph, which is constant, because you have the device up a tower. That equates to 4.45ms^-1, so working backwards, and assuming 50% efficiency for the 'k' factor - hey, we're geeks, we'll buy th every best - you'd need a blade disc, um, 5.4 metre diameter. Of course the conversion to electricity incurs losses, sy 80% overall... so a (*very* efficient) wind genny rated for1Kwh output at 10mph would imply a 5.9m diameter swept area. Pretty small!

      In fact, in the interests of minimising noise and improving part-speed efficiency, you'll find 1kW rated wind generators are slightly bigger, and rely on rather higher mean windspeeds. Beware the windspeed measurement though, that V^3 term will kill ya. If the mean windspeed locally turns out to be just half what you measure, you'll get, at best, only 1/8th the output expected. The actual design considerations for wind turbines (disc solidity, operating range windspeed etc) are wonderfully technical and pretty interesting in their own right.

      As to why not...well small wind gens are rather expensive , and Planning control (local ordinances, US) tend to restrict the possibility to rural areas.
  • Coralized (Score:3, Informative)

    by va3atc ( 715659 ) * on Saturday October 02, 2004 @01:12PM (#10413868) Homepage Journal
    The Coral links of "The pictures [nyud.net] are quite [nyud.net] impressive [nyud.net]"
  • by ShatteredDream ( 636520 ) on Saturday October 02, 2004 @01:13PM (#10413877) Homepage
    Some nerd is thinking, "where can I get THAT kind of power for my beanie....."
  • by yog ( 19073 ) on Saturday October 02, 2004 @01:14PM (#10413881) Homepage Journal
    This is a great idea. Why aren't we fully exploiting the power of the wind?

    This [saveoursound.org] is an example of the obstacles that American power generating windmills are facing. If ever there was a NIMBY group it's these people. Someone wants to build an offshore set of windmills to power [boston.com] about 3/4 of Cape Cod and surrounding areas in Massachusetts. Since Massachusetts is heavily dependent on important electricity and oil, this seems like a great solution.

    Undoubtedly there are some ecological implications, but the NIMBY group clearly is magnifying these issues in order to shoot down the whole idea; they're fishing for excuses. They don't want to have to look at windmills. This is where some federal leadership may be required in order to get the U.S. off its foreign energy dependency.

  • Wow. That's enough to power a small town. How much noise would a thing like that make?
  • I'm always impressed by 'Proofen Technology'.

    Checkout the cool 5M CGI here [repower.de]

    and Video [repower.de] Mirror [100bigcoupons.com](13MB)

    Images Mirrored:
    1 [100bigcoupons.com] 2 [100bigcoupons.com] 4 [100bigcoupons.com]
  • That would work wonders in hurricane season!!!
  • ...to move 3 18ton rotor blades? The inertia is tremendous. And what about friction on something so stupendously heavy?
  • by twitter ( 104583 ) on Saturday October 02, 2004 @01:24PM (#10413949) Homepage Journal
    5MW is impressive. Still, I'd like to put than number in perspective. It takes 200 of them to be the equivalent of one normal nuclear power plant, if and only if the wind blows continuously. The wind does not blow that way, it generally blows at off peak hours so power storage is mandatory. If that gets cheap enough this will be practical.

  • by KenFury ( 55827 ) <kenfuryNO@SPAMhotmail.com> on Saturday October 02, 2004 @01:45PM (#10414073) Journal
    Wind in the southwestern deserts and midwest plains away from most everything else. Solar would work in the south in general. Hydro in the north. If you take NYC (niagria falls), SoCal (solar and wind), Boston (from QuebecHydro)Texas (solar and wind), Flordia (solar) you are 25% of the way there. That is a big cut. Should drop existing energy prices and reduce greenhouse emissions as well. Add in some good insulation and, while you dont have the problem licked it is a big step in the right direction.
  • by phkamp ( 524380 ) on Saturday October 02, 2004 @02:08PM (#10414236) Homepage
    This site http://www.windpower.org/ which the danish wind generator producers have put up contains a lot of useful information about windpower and counters most of the FUD you'll hear.

    Wind power is not perfect, but it is here now (as opposed to fusion energy) has no waste problem (as opposed to current atomics) has local and well understood failure modes (things break, fall down) Produce a lot of power when we need it most (wind is driven by energy from sunlight) and it is economically competitive.

    The key to a sensible energy future is to not be fanatical for/against any one source, but to exploit them all where and how it makes sense.

    • The key to a sensible energy future is to not be fanatical for/against any one source, but to exploit them all where and how it makes sense.

      Yeah, human furnaces are really being ignored here.

      When I die I want to be contributed to the energy grid.
  • by Animats ( 122034 ) on Saturday October 02, 2004 @02:32PM (#10414408) Homepage
    Optimal wind turbine size has been creeping up over the years. The first big wind turbine, at Grandpa's Knob in Vermont, was 1.3MW. It ran from 1941 to 1942, had a bearing failure, and was repaired in 1945, after which it had a loss of blade accident due to overspeed.

    When wind power started to come back after the 1973 energy crisis, useful sizes were much smaller. There were a few big machines, but they were one of a kind prototypes. Most of the turbines of the 1970s and 1980s were in the 100KW range. That's a convenient size, because all the components can be shipped easily. The entire hub/generator unit can be shipped assembled.

    But all those little turbines are a maintenance headache. Farms of big mills generate more power per acre than little ones, because the blades are higher and catch more wind. So size has been creeping up. As the 1970s units wear out, they're being replaced with fewer, but larger, machines. New wind farm machines are running around 1.5MW. That's a commercial technology. General Electric alone has 2300 units of its 1.5MW turbine [gepower.com] installed.

    Offshore, much bigger machines are the norm. Setting a pylon in the ocean is a big job, so the fewer the better. Big components can be moved in by ship, so the truck size limit goes away. So offshore machines are running around 5MW. But there aren't many of them. Most of the really big machines are still experimental.

    Wind power is like hydroelectric power. There are a limited number of good sites. Most of the ones in California, the major passes through the coastal mountain range, are already taken. The East Coast doesn't have a long coastal mountain range, so installing wind farms in passes is out. So the East Coast systems tend to be offshore.

    Total installed wind turbine capacity worldwide is about 40 gigawatts, although that's peak, not average, output. This is up by a factor of 10 in the last decade. Much of this is due to better power conversion technology. Early wind turbines synchronized the blade itself to the power grid. Newer ones have inverters and better controls, so they interface much better to each other and the power grid. Many of the early turbines were only tolerable on grid because they were such a minor portion of generation. They were a destabilizing influence, forced into synch by bigger generators elsewhere. With improved controls, wind generators can contribute to frequency stability, rather than stressing it. As wind power becomes a larger fraction of generation, that's essential.

    • Most of the ones in California, the major passes through the coastal mountain range, are already taken.

      I must say, I find this assertion pretty ridiculous.

      I happen to live in CA, and I've seen a couple wind-turbine fields. The fact of the matter is, there is a huge desert here, meaning both that there are no trees or anything of that sort to get in the way, and the tempurature contrasts are very extreme in a short area. I know from just living here that strong winds are both regular and nearly hurricane

  • by Webmoth ( 75878 ) on Saturday October 02, 2004 @03:19PM (#10414768) Homepage
    The Stateline Wind Energy Center [rnp.org] in SW Washington and NW Oregon has the capacity to produce 300MW of energy, one of the largest installations in the world to date.

    Granted, each turbine is only 660kW -- far short of the 5MW of the turbine mentioned above -- but all put together, with 454 turbines, it makes for a sizeable facility. Plus with lease payments of $1500-2000US per turbine, it provides farmers with their biggest cash crop since marijuana.

    Yes, there's photos [rnp.org].

Mathemeticians stand on each other's shoulders while computer scientists stand on each other's toes. -- Richard Hamming