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Clean Power

Published on July 5th, 2016 | by Joshua S Hill


Vestas’ Multi-Rotor Wind Turbine Produces First kWh

July 5th, 2016 by  

Danish wind turbine manufacturer Vestas has announced that its multi-rotor concept wind turbine has generated its first kWh.

Earlier this year Vestas announced that it was installing a multi-rotor concept wind turbine at the Risø test site near Roskilde, Denmark. On Monday, on its Facebook page, Vestas announced that the multi-rotor concept turbine had produced its first kWh.

“Following satisfactory results of necessary tests, the multi-rotor concept turbine recently produced its first kWh according to the plan,” the company said on Facebook.


“Right now we are testing various software functions,” explained Erik Carl Lehnskov Miranda, Senior Specialist, Electrical, Load & Control at Vestas. “One of them is the cut-out functionality, i.e. if the concept demonstrator stops when it reaches the cut-out wind speed. Another one is the yaw system supervision that shuts down the turbine in case the yaw misalignment exceeds certain values.”

The multi-rotor concept turbine will undergo a series of tests and monitoring over the next few years to determine the design’s feasibility, specifically the technical feasibility of operating and controlling a multi-rotor turbine.

“Installing a concept turbine shows that innovation sometimes entails entirely new thinking and new approaches,” said Jorge Magalhaes, Senior Vice President, Vestas Innovation & Concepts, in April. “This process of continuous innovation and exploration is extremely important. It provides us with essential knowledge that can help us bring down our products’ cost of energy and integrate key technologies to solve our customers’ challenges. Ultimately, the goal is to assess if we can build an even more cost-efficient turbine by challenging the scaling rules.”

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  • Karl the brewer

    1 kwh generated. That will play havoc with its CF 😉

  • onesecond

    I am a big fan of gigantic wind turbines. The bigger they are, the fewer you need and their long blades need much longer for one rotation so they seem slow-moving and don’t get hectic. This design on the other hand is aesthetically really unpleasing and the small rotors will spin like hell.

    • Bob_Wallace

      Small, fast spinning rotors might put us back into the bird kill problem area once more.

      • Vance Vance

        I haven’t looked for statistics; is smoke from electric generating plants also harmful to birds? Beijing often looks like a return of the “Great Smog” of London in 1952–those five days in December may have resulted in upwards of 12,000 deaths (people, not birds).

        • Bob_Wallace

          The issue is not whether coal kills more birds than wind.

          The issue is whether faster spinning blades installed closer to the ground might take us back the the “Altamont” problems. If bird kill rates are significantly higher than the designs in use now this design will have problems.

          • Vance Vance

            How much faster? What is the tip speed never to exceed? Why would thousands of installations of this exact rotor size and design pose a fresh problem? I haven’t referenced Altamont problems…could it have had to do with turbines located within migratory travel? Why is a name associated with “the bird kill problem area” if it is actually a function of size/speed?

          • Bob_Wallace

            It’s not tip speed. The tip speed of large rotor turbines is very high but because of the slow rotational speed the rotors are very easy to see and track.

            Altamont had multiple problems. It is a migratory route.

            Many of the towers were lattice rather than monopoles. That gave hunting raptors a place to perch while they watched for small animals on the ground. When they spotted prey they would often launch themselves off their perch and into the fast spinning rotors.

            And the early turbines, the sort installed there over 30 years ago, had small, fast rotating rotors.

            If you stand and watch a large wind turbine turn, even in high winds, you can see that the blades are very visible and easy to track.

          • Vance Vance

            Copied and pasted from a story about Altamont Pass: “More recent studies, however, are showing that the new models kill more birds per individual turbine because they reach into air space used by high-flying raptors and have a much wider rotor span.”
            So…I’m sure that turbine testing, research and manufacture in any part of the world is aware of California but I doubt that Altamont’s mountain pass peculiarities are applicable to most wind farm installations. That would be like suggesting that every bridge could fail as spectacularly as Washington’s Tacoma Narrows bridge. The lesson of Altamont is probably now a function of preliminary site suitability rather than “the sky is falling!” rotor size/speed.

          • Bob_Wallace

            That’s a comment made on a blog but there’s no link to the studies.


            I found reference to a single study –

            “Thousands of older turbines at Altamont Pass have been fast-spinning and low to the ground, while also featuring cage-like lattice towers that were attractive places for birds to land and perch: a bad mix.

            Most of these are being replaced by “monopole” towers, some as high as 500 feet (152 meters). The new towers are meant to be safer for wildlife, but a recent study suggests that may not be the case. Looking at hundreds of published reports on bird deaths at 59 wind farms across the United States, Oklahoma State University ecologist Scott Loss says the shift to the new, monopole designs is no simple fix.

            The larger, more efficient structures appear to kill more birds per turbine than the windmills they’re replacing—between three and eight birds per turbine per year, according to Loss.”

            There’s a problem with data interpretation. The critical metric is not birds killed per turbine but birds killed per GWh of electricity produced.

            The original turbines at Altamont were very small compared to today’s turbines. There are several companies that have turbines at Altamont, let’s look at one (the one I quickly found ;o).

            Wiki –
            ” 100kW Kenetech turbines are being taken down. These are older models with lattice towers. It has been proposed to replace them with 27 turbines with rated capacity of 2.1MW”

            For each “higher turbine” installed 21 “lower turbines” are being removed. (2.1 MW / 100 kW = 21)

            The new, higher turbines would need to kill more than 20x as many birds per tower in order to be equally dangerous for birds. If the lower turbines were killing, on average, 1 bird per year then they were a lot more destructive than the higher turbines that are killing “between three and eight birds per turbine per year.”

          • Vance Vance

            Okay then…please step slowly away from Altamont Pass and migratory birds–besides all that kerfuffle, I admire Vespas for its ideas. A while ago, I came across research having to do with schools of fish and closely-spaced vertical turbines. See, the thing is, we’ve simply been alive to watch new things being developed. Nothing useful comes to fruition without problems–that’s why Vespas has built this concept. No one is saying that it will be manufactured and sold. Everyone in the ‘biz’ understands birds well enough now to render your caution moot.

            I look forward to high-flying generators, tethered with what may become space elevator cable, no matter what material it’s made from; I favor carbon nanotubes for both strength AND electrical conductivity. Perhaps a process to harvest CO2 and build from it continuous, unbroken filaments of carbon nanotubes. We are in process, but have yet to reach a Type I level of civilization as defined by Kardashev.

          • Bob_Wallace

            I have no problem with Vespas testing the idea. I simply pointed out a potential problem that needs monitoring.

            Clusters of vertical turbines, kites, solar roads – all sorts of things are “interesting”. I’ve got no problem with private money spent on evaluating ideas. But let’s wait until the ideas are proven before we take them past the point of testing.

            Here’s a technique that I use to guess what may or may not be used in our future energy systems. If an idea isn’t picked up venture capitalists then it is probably not going to work, at least in its current form.

            There are many investors searching for good ideas that they can help turn into money machines. They have teams of experts they use to evaluate an idea to see if it has merit. Because they are potential investors their specialists get to peer into the innards and check out all the nuts and bolts. No one invests serious money based on a press release.

            If an idea has been public for a few years and is still having to fundraise then there’s probably not much to the idea.

          • Jenny Sommer

            These stupid solar roadways are obviously a bad idea but they are done anyways. France, Netherlands and now route66 if the news is real…

            I still don’t understand how you can mix solar roadways in with high altitude wind power.
            It is just not obvious that HAWES won’t work. In fact there is a huge potential there.
            It’s not a small inventor either but here are some serious engineers and technical universities working on solutions.
            You won’t find whole departments of ETH Zürich or TU Delft working on solar roadways…
            The 3MW Kitewing is real.
            Will you ignore that one too when they are flying it or does it at least merit an article like Vestas Quad setup (it’s the third at least btw.)

            Maybe the VCs just don’t have the tools to verify this particular technology. Maybe there are things easier to understand or that just yield more money in the short run.

          • Bob_Wallace

            Solar roadways and clusters of vertical wind turbines are just as real as generator kites.

            Prototypes have been built. The data produced has not brought either into the commercial arena.

            If either produce data that shows they work – and – independent analysis shows that the electricity produced has a chance of being competitive on the market then I’ll move them from the “only interesting” to the “possibly useable” category.

            “Maybe the VCs just don’t have the tools to verify this particular technology. ”

            Man, you are so totally blinded by your advocacy. If it’s something that located within about 300 miles of where you live it’s a special snowflake.

          • Jenny Sommer

            They could be on the other end of the globe for what I care. What do you know about their prototypes and testing…

          • Bob_Wallace

            I know that what they’ve produced to date – prototypes, data and ideas – has not been enough to get monied people to back them.

            And I’ve seen venture capitalists take some on some very long shots.

      • Brooks Bridges

        Was there ever a real problem? I mean compared to cats and windows in buildings. Oh, and as mentioned below, coal power plants. And ultimately, climate change.

        • Bob_Wallace

          The comparison will not be made with cats. But with the turbines in wide use now.

          • Brooks Bridges

            The reasoning behind your statement is not obvious to me. There seem to be many variables.

          • Bob_Wallace

            This is a test to see if multiple smaller turbines on one tower produces less expensive electricity than a single turbine on a tower.

            I’m suggesting that economics might not be the only variable that might come into play. Faster spinning rotors may kill more birds.

          • Brooks Bridges

            I understand the possibility – just sounds like the least of their worries right now.

      • eveee

        This is a prototype intentionally using older, smaller tech, to ease evaluation. I expect later ones will be at least 1MW each rotor, just not 8MW rotors. For land based designs, the current standard is about 3MW single rotor. That would be replaced with four 1MW rotors on a taller, cheaper, tower, for less cost. Eventually, it could be 4 3MW rotors. That’s how the land based wind limit can be overcome. I see no advantage or trend going back to smaller rotors. It’s all about getting past the weight limits on top of the towers, and the manufacturing and transport problems of long rotors without excessive cost. It effectively lowers the cost of wind energy, if it works.
        We will start to look at sub 2c/kwhr energy onshore and higher CF.

      • sjc_1

        “Wind turbines kill between 214,000 and 368,000 birds annually — a small fraction compared with the estimated 6.8 million fatalities from collisions with cell and radio towers and the 1.4 billion to 3.7 billion deaths from cats…”

    • Vance Vance

      Vestas built thousands of 29 meter diameter single rotors from 1990 to 1997. This concept incorporates four of them, refurbished. Compared to a larger swept disc diameter, yes, they can be considered small, but these blades are also pitch-controlled, which means ‘hell’ doesn’t happen during high wind speed. To me, form follows function; no matter what they look like, wind turbines deliver electricity while giving back our clean, natural atmosphere. Smoke from coal-burning electric generation is not only “aesthetically really unpleasing,” but environmentally harmful.

      • onesecond

        Of course I still would prefer even this design a lot over coal and nuclear power. I just like giant wind turbines with a single rotor much more.

        • Jenny Sommer

          Conventional turbines are a dead end.
          Head over here if you like a discussion on the future of wind power.

          • onesecond

            Well, in my view people tend to underestimate how far conventional turbines have already come in scale and capacity factor. With carbon concrete and new material compositions for the wing they can still grow a lot. The other concepts might be feasible but it a lot harder to actually catch the established wind turbines on cost. Start ups are very optimistic of course but scaling their concepts up is a lot harder than building a small prototype. I would be surprised if one of those concepts will win on costs in the next decades but I don’t mind to be proven wrong.

      • eveee

        They are also a test bed, so using smaller rotors than intended in final versions. The production ones could be multiple low MW scale rotors.

  • Adrian

    Seems like it would be tough for a multi-rotor design to exceed the swept area of a single rotor, but I suppose the blades and nacelles are much smaller and easier to transport.

  • Kevin McKinney
    • Harry Johnson

      That was helpful. It makes sense that ever-larger components themselves become a problem of weight and stress. And then there is the problem of transporting huge turbine parts on existing roads. Segmented towers and blades assembled on site are the only answer if bigger turbines are the direction forward. Right now new transmission is what’s needed most.

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