Published on April 24th, 2014 | by Michael Barnard


UGE Vertical Axis Certification: Behind The Hype

April 24th, 2014 by  

VIsionAIR5-micro-wind-turbineUGE has taken an excellent and necessary step, one most small wind turbine manufacturers never do: they have had independent certification of one of their devices performed. A wholly praising article was published in CleanTechnica on April 22, 2014, just a couple of days before this article.

The article, as with most press on the subject, made several positive points about the UGE, some accurate, some slightly less so, but any actual analysis of comparative output of generation and implications for lifecycle costs of electricity was conspicuously missing. This is a fairly critical point when considering wind generation technologies.

Let’s make one thing clear: I like UGE as a company. They sell complete renewable energy solutions including solar, wind, and inverters at a not unreasonable price with packages for residential and industrial settings. The UGE VAWT is an attractive device and some people will be willing to pay a premium for aesthetic values as our previous article points out. I have no problem with people who have lots of money spending it on good-looking objects that generate reasonable amounts of electricity. Personally, I’ve paid a premium based on aesthetic reasons for consumer electronics, vehicles, clothes, furniture, and a number of other things, so people basing part of their decision on that factor is completely reasonable. UGE services a specific subset of the renewables market. It has a solid track record of growth and a partner model which extends its reach. It’s a good business model and the helical vertical axis wind turbine is part of their chosen differentiation.

But feeding the vertical axis wind turbine hype mill as these articles tended to do is a bit more problematic, as it makes it seem as if certification implies equivalence to horizontal axis wind turbines, which isn’t the case. And pretending that this will make a significant difference to wind generation is also problematic.

The UGE certified device appears to be the VisionAir5. It has a published power curve, although it’s unstated whether it is the same one provided by and certified by Intertek. It’s labeled as 5, which implies something in this space, as more often than not numbers in the name of devices denote the nameplate capacity rating in kilowatts or megawatts. However, the VisionAir5 has a listed power output of 3.2 KW in the table of specifications. Even there, some inflation appears to be occurring, as the actual power curve shows an average power of 2.5 KW.

It’s worth comparing this to a power curve for a similarly rated HAWT, but it’s a bit tough as the VA5 is rated at 3.2 KW, which is an unconventional number. However, let’s take the Bergey Excel 10 KW device as a comparison. I would have used the 6 KW Bergey device but the link to the certification report was broken at the time of analysis. At least right now, Bergey publishes their certification report, while UGE doesn’t.

Screen Shot 2014-04-23 at 2.12.38 PM

I’ve scaled the power curves to be easily comparable along the horizontal axis. Something that leaps out is that the Excel 10 actually has a peak power output of 12.5 KW but is labelled a 10 KW device, while the UGE has a maximum 3.2 KW output and that is the referenced output. An apples-to-apples comparison at the same 11.5 m/s wind speed shows that the UGE is actually comparable — by that simple and reductive measure — to a 1.8 KW device, not a 3.2 KW device. UGE claims an average power of 2.5 KW in their power curve material if not their other documentation, which is likely the number that is most comparable.

It’s worth looking at swept area and comparable production as well. While VAWTs tend to be mounted lower with most of UGE’s home material showing very low mounting on rooftops and the like, let’s ignore the mast height for now, assuming if you were serious about wind generation you would put the device as high as possible. The Bergey 10 KW device for example is specified usually with a 30 meter (100 ft) mast. I’ve created equivalent Bergey scaling for swept area assuming lowered power ratings, knowing that power output is linear with swept area all else being equal.

Screen Shot 2014-04-23 at 2.46.26 PMIt’s pretty obvious from the table that at the maximum UGE power output, the Bergey would require only 74% of the swept area to achieve similar output at its nameplate capacity, an already unfair comparison as this isn’t Bergey’s maximum output but its 11.5 m/s output. The comparison just gets more and more in favour of the Bergey as more realistic comparisons are made at 2.5 KW and 1.8 KW, with a Bergey device only requiring 58% or 52% of the swept area to achieve similar output. VAWTs already require substantially more material — a key factor in cost of manufactured objects — than HAWTs for the same swept area.

Paul Gipe has done this analysis already in his comments on the UGE announcement, so I will quote him.

Worse, UGE’s data confirms the fundamental disadvantage of most VAWTs, they are much more material intensive than conventional wind turbines. The relative mass of a wind turbine—a measure of its material intensity that includes the rotor and nacelle—is often used as a shorthand for its expected cost. The more the relative mass of a turbine, the more its likely cost. The specific mass of UGE’s VisionAIR is four times more than Bergey’s Excel 6.

However, beyond relative mass for the same swept area, the analysis shows that for equivalent power output, much more swept area is also required, so the additional cost of materials is then further multiplied by a factor of almost two. Mr. Gipe’s analysis of relative mass shows that it’s over four times more.

These pretty basic comparisons show the reason why the lifecycle cost of electricity (LCOE) for horizontal axis wind turbines is always better than the LCOE for vertical axis wind turbines. They have to sweep twice the area with four times the material to achieve the same capacity. Added to this is that they are so often sited in very poor wind resources with masts that are too short because of their ‘advantage’ of being able to catch turbulent air, and the capacity factor drops tremendously.

This is something our previous article got backwards when put in relative terms. “The vertical system is far more compact than the now-familiar horizontal axis wind turbines,” that article stated. It’s true the UGE 3.2 KW device is much, much smaller than utility scale wind turbines, but if it were scaled up it would have to be twice as big and four times as heavy, with a correspondingly more robust tower. The Bergey 10 KW device is also much smaller than a utility-scale wind turbine, but if scaled up would be roughly the same size.

Our previous article had it right that the certification raises the bar for the also-ran category of vertical axis wind turbines, making it even harder for this lesser technology to get a foothold. That’s probably a good thing, but it also is a double-edged sword for UGE as they try to convince people that their obviously inferior certified results are still worth investing in.

On the noise issue as well, it’s important to not buy the hype over the substance. UGE makes the claim of being extremely quiet, but what do the numbers say? Well, their published numbers state 38 dBA as the noise of the VisionAir5 device. The Bergey Excel 10 is rated at 42.9 dBA, and the rated 4.9 dBA is an audible difference to human ears although not an enormous one. But that additional 4.9 dBA comes with three to four times the electrical power generation. UGE claims that their uncertified UGE 9M device is <38 dBA at 12 m/s, which is interesting as they scaled it up by a factor of roughly four yet assert lower noise; this is unlikely and certification would clarify this. It is possible of course, as VAWTs just can’t spin as fast due to inefficient capture of airflow, but it’s unlikely.

605_uge1k1s_1274802346This only becomes important in a minor way if you were to put this device on the roof of a house over a bedroom, which UGE implies is reasonable but Bergey doesn’t begin to think is reasonable. The Bergey device with its 30 m mast would see attenuation of noise down to about 40.5 dBA at the base of the mast, which is close to World Health Organization noise recommendations for nighttime noise already, and even then Bergey devices aren’t put right beside homes typically but where the air is cleanest in a paddock. The only real value that the UGE statement of quietness brings is that with a really small, low output device you can put it on top of homes where the wind resource is poor without disturbing peoples’ sleep. This isn’t necessarily a great tradeoff as it takes an inefficient device and reduces its effectiveness further.

It’s great that UGE went the extra mile and became certified. But it isn’t particularly transformative. What will be transformative for the distributed small wind market is the new United Wind offer combining excellent analytics of output and fiscals with Bergey and other certified horizontal axis wind turbines, allowing guaranteed returns and a no-money down lease. But that article is still brewing after my conversation with the CEO this week.

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About the Author

works with startups, existing businesses and investors to identify opportunities for significant bottom line growth in the transforming low-carbon economy. He regularly publishes analyses of low-carbon technology and policy in sites including Newsweek, Slate, Forbes, Huffington Post, Quartz, CleanTechnica and RenewEconomy, with some of his work included in textbooks. Third-party articles on his analyses and interviews have been published in dozens of news sites globally and have reached #1 on Reddit Science. Much of his work originates on, where Mike has been a Top Writer annually since 2012. He's available for consultation, speaking engagements and Board positions.

  • Ronald Brakels

    Now that Australia utilities have seen the light and are going to replace grid power with self generation and energy storage in remote areas (where in the most extreme examples households are subsidised at the rate of $14,000 a year), there is a great opportunity for small scale wind to to play a role in reducing the size of battery banks and diesel use. Given the amount of wind resources available in some communities, it would be kind of tragic if small scale wind could not offer the kind of prices and warranties that are required for it to play a role. Well, it would be beyond tragic, it would be pathetic.

    • But it’s more likely to be like the current King Island Tasmania situation, where a small utility-scale wind farm and storage is providing the generation, not small scale wind turbines under 100KW.

      • Ronald Brakels

        King Island has a massive population of over 1,500 people and is in the roaring forties. Something like the Kooma Country community has many kilometers of cable connecting it to the grid and an average population of a dozen or so. If wind is going to play a role there it is going to be small scale.

        • I hadn’t realized you were talking about places that small. You’re right, small wind turbines are the appropriate scale for that.

          I can only imagine the weird political configuration that made it seem as if subsidizing people to live in the middle of nowhere was a good idea.

          King Island is down to about 1100 people by the way. The major wind farm being assessed for there would enable it to have a more robust economy again which would attract more business and people, but right now it’s hurting badly.

          • Ronald Brakels

            In general it is the smaller places that are the most expensive to maintain supply to. I am guessing that the small farms and communities on the end of lines that lead off from the main line will be pruned off first and then we’ll be left with a string of towns with grid power along the mainline. If the cost of going off grid is cheaper than keeping them on grid then they will be cut off one by one, or they will use the main line to send solar power back east to the coastal cities after their sunset. However, as storage costs will come down this may not be economical.

            As for the weird political configuration that made it possible, well, lots of white people used to live in those areas. And when you get down to it rural electrification was only really different in scope rather than kind from say US rural electrification and was driven by similar reasons. The benefit electrification made to people’s lives was considerable. Whether it was the best thing that could have been done for people in these areas for the money is debatable, but it contributed to social welfare. And then of course there were things like the Queenland Gerrymander that made rural votes worth more than city votes which wouldn’t have hurt the amount of money going into rural infrastructure.

          • Ronald Brakels

            Where did they go? In 2012 King Island was supposed to have over 1,600 permanent residents, not 1,100. Well, it’s right next to Tasmania so I guess the result would all depend on if you counted heads or bodies.

          • Away. The mine closed a while ago. The cheese industry was bought buy a multinational which is trying to become vertically integrated, cutting cheese lines and the like.

            Asking where they went is like asking how do you keep them down on the farm once they’ve seen the city.

          • Ronald Brakels

            Ah, I see. Someone cut the cheese and they all left.

          • Bob_Wallace

            I knew you wouldn’t be able to leave that one alone….

    • Bob_Wallace

      Something that might be considered is a refurbished smaller commercial turbine.

      Germany (and I assume other) countries with limited space for turbines are taking down the smaller capacity ones they installed earlier and replacing them with larger units. These used turbines are being refurbished and sold to places with larger resource areas and less capital to invest.

      • Ronald Brakels

        I don’t think refurbished turbines would do the trick because here maintenance costs are a killer. Not only do you have to pay a lot of money to get things fixed in Australia, you have to pay their hourly rate while they travel out to a remote area and then back again. Sure, if the price was right it could be done, but I’m sure other countries without sky high maintenance costs would be willing to pay more than what the the old wind turbines are worth to Australia. Still, it was a good suggestion.

  • spec9

    I’m still highly skeptical of these vertical axis turbines. They generally don’t seem very efficient.

    • Hans

      Wasn’t that one of the points of the article?

  • Peter Gray

    Hans: I could have written exactly the same comment myself. Mike’s articles and reviews are consistently of the highest quality, and Cleantechnica deserves praise every time they post his work.

  • Hans

    I often criticised Cleantechnica for publishing paraphrased press-releases on questionable products. Now it is time to complement Mike and Cleantechnica for this insightful critical review.

  • Ronald Brakels

    Good review. I would have to see small wind turbines take off in rural and remote Australia, which I guess would be a perfect market for them, before I could believe it would make sense to install them in urban areas. So far it’s not really happening, but fingers crossed we are getting closer. A little extra generation when the sun’s not shining would be very useful for a lot of people off grid.

    • Bob_Wallace

      Small is simply not beautiful when it comes to wind turbines.

      There’s a great dream that we’ll all mount an eggbeater above our gardens and gen lots of cheap power. Wasted money.

      • Ronald Brakels

        Even in crazy land where I live they aren’t making much inroad in the off grid market. And here in Australia we have a guy who says he can hear wind turbines that are 80 kilometers away. Imagine what putting small ones in town would do to him. The wind would start blowing and it would be like a scene from Scanners.

      • Michael Bergey

        The steady stream small wind hustlers and penny stock promoters who have promised a pint sized wind turbine on your roof or on a 10 ft pole in the garden would power your house have done a tremendous disservice to the legitimate small wind industry providing HAWT’s on reasonable height towers. Certification of turbines is working to stem these frauds. But, don’t forget that there are tens of thousands of happy small wind turbine owners and that sales of small wind turbines are increasing in spite of huge subsidy favoritism for solar and large wind over the past 20 years.

        • Bob_Wallace

          Small wind can be an excellent choice for off grid generation. I have friends who have good wind sites and get most of their electricity from small HAWTs. (I have 80+ foot Doug firs.)

          I’ve never seen any numbers that show that someone on the grid can install wind and save money on electricity. (Full accounting including hardware and maintenance costs.) Does your math say otherwise, Michael?

          • Michael Bergey

            Well, of course it does, Bob. Just like the math that says people installing solar can save money. Most of the sales revenue in the small wind industry is from on-grid systems installed by homeowners and farmers to save on their electric bill. A typical 10 kW wind system is saving a homeowner $150-$250 per month. “No money down” leases are available. And, you might be surprised at how many are installed on towers 120-160 ft tall (so 80 ft trees are not a barrier).

          • Bob_Wallace

            Michael, I’m assuming that the homeowner has already installed solar. That, IMO, is the low hanging fruit.

            If solar is installed there’s little room left for wind. That’s my case. Of course I could use a taller tower and get into clean air. But that’s a lot of money to back up my solar system.

            From your site – “A 10 kW wind turbine costs approximately $48,000 – 65,000 to install.” I burn a few hundred dollars worth of gasoline per year in my generator. I’d never recover the cost. A wiser route for me is more panels and, perhaps, more storage.

          • Michael Bergey

            Your flip-flops from off-grid and on-grid opinions is confusing. And, IMO, your off-grid home situation really doesn’t have anything to do with whether small wind can be beneficial to an on-grid homeowner.
            But, back on off-grid situations, we sell quite a few 1 kW turbines for remote homes where a combination of solar and wind provides more reliable renewable energy generation and lowers the use of the back-up generator. Wind works at night and during the winter, which augments solar at may locations.

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