Multi-megawatt Wind Turbines

RE Power’s “5M” offshore wind turbine is definitely the King of wind turbines – a single unit that generates 5.0 megawatts of electricity at full output. With a rotor diameter of 126 meters (412 feet) and a hub height between 90 and 120 meters, RE Power’s 5M unit is the biggest wind turbine available in the world, with a total height up to 183 meters (max. hub height plus rotor radius – 600 feet). It represents the next generation in large scale wind. With this turbine, a 200 tower wind farm would generate 1.0 gigawatts at full output. Wind turbines this big are game changers, because the fewer towers involved, the more efficient wind power becomes, especially offshore.

RE Power’s 5M is designed for offshore use, and testing is now completed on twelve 5M turbines, operating both onshore and offshore.. The first one, intalled onshore in Brunsbuettel, on the west coast of Schleiswig-Holstein in Germany in 2004, has logged over four years of 95% availability. In the Beatrice oil field, 25 kilometers off the Scottish East coast, in open ocean 40 meters deep, RE Power has installed two 5M turbines. RE Power is planning to install six 5M turbines offshore near the island of Borkum in the first phase of a new German offshore wind farm, and to begin series production of the 5M in Bremerhaven.

RE Power 5.0 MW offshore wind turbines.
Beatrice oil field, North Sea.
(Photo: RE Power)

It doesn’t end there, nor should it. RE Power intends to produce the next size up, a six megawatt wind turbine at the same plant in Bremerhaven.

It is very interesting to wonder at what point the output per unit reaches its practical limit. Are ten megawatt units possible? What about the colossal land-based vertical axis concepts, where a single unit might generate 100+ megawatts? Can wind power get cheaper as unit capacity increases, and who else manufactures multi-megawatt wind turbines?

GE Wind Energy offers the new 3.6 MW Series that, according to their website, “is a larger version of our proven 1.5 MW design, the 3.6 MW machine was specifically designed for high-speed wind sites. With a rotor diameter of 104 meters and a swept area of 8,495 square meters [2.1 acres, the area covered by the three 52 meter fans, turned to the wind], this new wind turbine is ideal for offshore markets worldwide.” The 3.6 Series is the next evolution of GE Energy’s wind turbine fleet and builds on the success of GE’s 1.5-megawatt machines, which are among the world’s most widely used megawatt class wind turbines with more than 8,600 units in service and more than 125 million operating hours.

Not to be outdone, Siemens also offers a 3.6 megawatt wind turbine unit, the “wind power station” SWT-3.6-107. With an 80 meter (or site specific) hub height and a blade length of 53 meters, with one of the three blades pointing skwards this unit stands 133 meters high (436 feet).

Vestas Wind Power Solutions has over 500 3.0 megawatt units installed around the world with their V90-3.0, which actually weighs less than its 2.0 megawatt predecessor. Fuhrlaender has the FL 2500, a 2.5 MW turbine that has a modular design, allowing this output to be achieved using variable rotor speeds, and an assortment of rotor diameters, 80, 90 and 100 meters – as well as lattice towers up to 160 meters. At a hub height of 160 meters and a rotor radius of 100 meters, each unit has an amazing total height of 210 meters (689 feet).

Nordex offers three 2.5 megawatt wind turbine products, the N100 with a 100 meter rotor diameter designed for low speed inland locations, the N90 with both low and high speed variants, and the N80 designed for high winds. Enercon manufactures the E-70 wind turbine with 2.3 MW rated power and numerous steel and precast concrete tower versions – is especially suitable for sites with high wind speeds.” The E-70 has a rotor diameter of 71 meters (233 feet) and a hub height ranging from 58 to 113 meters. At a hub height of 113 meters and a rotor radius of 35.5 meters, this unit has a total height of 148.5 meters (487 feet).

Another company with a wind turbine that exceeds 2.0 megawatts is India based Suzlon Energy, who has a 2.1 MW unit noted on their product page. Gamesa offers three models of “aerogeneradores” that all attain 2.0 megawatts, optimized in various ways with the G80, the G87, and the G90. Finally, AAER Wind Energy offers the A-2000, rated at 2.0 MW, with “an optimized torque control system combining variable-ratio superposition gear (SPG) with individual pitch control of the blades. This means that it can be operated at optimum aerodynamic efficiency throughout the whole operational range.”

When considering wind power, cost and impact are major considerations – wind power is relatively competitive based on cost. But how many wind power stations can you build? Finding sites and establishing transmission corridors is most of the battle with wind power, so the bigger the unit, the better. Still the scale of these machines is daunting – many of these wind power stations have total heights exceeding 500 or even 600 feet. By contrast, the Statue of Liberty only measures 305 feet from the water to the tip of her torch. How many of these units would replace a 1.0 gigawatt nuclear power plant?

At 5.0 megawatts each, and a 25% yield, you would need 800 of these machines. At 2.5 megawatts each, you would need 1,600 of them – that is a very, very large wind farm, on-shore or offshore. If they are placed on a grid a safe distance apart, say 500 meters (remember, they are up to 200 meters tall), then 1,600 of these units would consume an area of 200 square kilometers. At 5.0 megawatts per unit, but 1,000 meters between units, a 800 unit windfarm (25% yield) with generating capacity equivalent to a 1.0 gigawatt nuclear power plant would require 800 square kilometers, over 300 square miles. Each of these units would be nearly twice the height of the Statue of Liberty.

The world’s first 5.0 megawatt wind turbine, operating since
2004 on the southwest coast of Schleswig-Holstein in Germany.
(Photo: RE Power)

9 Responses to “Multi-megawatt Wind Turbines”
  1. Shanmugham Kangala says:

    Need for higher capacities 5 MW and higher for offshore installations can be justified.

    Recent trends in size shows a stagnation in the segment of 2-2.5 MW range and 90-93 m rotor sizes, which can be due to higher costs and problems in transportation. To my knowledge, there is no public record confirming that larger Wind Turbines provide higher specific power yield. One of the popular brand which could capture orders in excess of 3000 MW even before launching, had serious problems in Generator/gear assembly and blades. Another brand which claims to be holding major market share has very low specific power yield, but it is yet to be type tested for serial production.

    Cost effectiveness of MultiMW sizes should be backed up by field proven performance results.

  2. Build A Wind Turbine At Home in under $150. save the planet and be green.


  3. Alice Finkel says:

    The modular Hyperion nuclear reactor makes much more sense economically than these huge and expensive wind turbines. The nuclear reactor is safe and provides baseload power–all in a package that fits on the back of a flatbed truck.

    You can bury the reactor underground anywhere on the surface of Earth, thousands of miles from the nearest coastline.

    Those huge wind turbines would be awkward offshore, and present a navigational hazard. On low wind days they would sit there unused. They represent a huge waste of resources that could be better spent on baseload power projects.

  4. Lynne Benson says:

    I’m with Alice – why don’t you run some reports on the potential of thorium fuel, as well as reprocessing. These procedures are safer than ever, and suggest there could be a nearly unlimited supply of nuclear fuel.

  5. Alan says:

    Compare these wind turbines to the hundreds of oil platforms sitting in our oceans around the world. They will not present navigational hazards, they’ll be clearly marked on navigational maps. The more oil rigs we can replace with offshore wind turbines the better, I say. As the story says, the bigger the wind turbine, the fewer you need to generate an equivalent capacity.

  6. Cyril R. says:

    Hyperion reactors are a very promising design, but let’s not get ahead of the facts. They first have to licence the design, and then build a small number to prove the concept. We’re not talking GW scale at least until 2015 and likely a lot later.

    5 MWe wind turbines are already operating right now.

    Anyway, it’s kind of strange to see so many people in the blogosphere pit nuclear against wind. That’s a dangerous dichotomy, it’s too early to tell and we shouldn’t be picking one winner on such a subjective basis.

  7. Alexander says:

    Wind power is not a solution.
    The whole truth about wind turbines is never told by lobbyists and governments.
    How could the very weak and extremely unreliable initial energy source of a wind turbine ever produce a steady power of any significance?
    Please think!
    And read: “Wind energy- the whole truth” at:
    And to show how completely irrelevant wind power is in regard to the worldwide energy and climate crisis visit the following link:
    And play around with the charts you see there (The BP charts regarding energy reserves and energy consumption worldwide over the last 20 to 40 years.) and make some calculations. And if you don´t get confused with the zeros, you will get my point.
    The resources now poured into futile, but very ingenious and high-tech windmills, could be far better used for, for example:
    1) Burning coal in a cleaner way,
    2) Efficiency of energy use in the broadest sense of the word
    3) Promoting a drastic change of life style (There are about 6.5 billion people, who all have the right to have some energy to their disposal).
    Just 3 ideas.

  8. Dominique says:

    I think that it is time to stop thinking people are only nasty manufacturers, nasty greens, nasty non-greens, nasty investors, nasty producers, nasty polluters, nasty all-you-want.
    This is not constructive.

    Time has come to see the world as it is, its daily needs and its longer-term needs. Let the people build wind farms and start yourself changing drastically your life. There are some people cleaning the coal processes. you just do not know them.

    People who think that one ressource is The key are, sorry, mistaken. Because of the pattern of the consumption areas/needs, it is just silly idea. You need nuclear, you need wind, you need solar (even it produces more CO2 to produce than it saves, am I right?), you need hydro, and even a little bit of fossil energy, time to find something else.


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