In preparing for a review of a Sandia report on its decades-long research on Vertical Axis Wind Turbines (VAWTs), especially the Darrieus or eggbeater design, I thought it might be wise to first see what other information is out there on the web.
The experience has been enlightening, shall we say. I’ve come across entries that range from thinly veiled promotions of VAWTs to an extensive visual catalogue of VAWT experimentation, including a few photos from my own collection.
Since my native language is English I started with Wikipedia in English. Yes, in case any Anglophone is wondering, there are Wikipedia collections for many other languages.
I searched for VAWTs, Vertical Axis Wind Turbines, and Darrieus wind turbines. There are other versions, such as giromills and cycloturbines, but I didn’t go much beyond the standard vertical axis turbines.
The English Wikipedia’s entry Vertical axis wind turbine is of questionable value. While its introduction is useful in describing a VAWT, the remainder is not helpful if not deliberately misleading. Parts of the entry read like a sales brochure for VAWT producers. For example, here’s one paragraph that caught my eye.
“VAWTs are rugged, quiet, omni-directional, and they do not create as much stress on the support structure. They do not require as much wind to generate power, thus allowing them to be closer to the ground. By being closer to the ground they are easily maintained and can be installed on chimneys and similar tall structures. “
This is the kind of over-the-top text that gets my hackles up. For starters, the citation doesn’t lead anywhere so there’s no way to check the credentials of the author. Nevertheless, the 2004 article cited is traceable via Google. There we find that the author is a promoter of his own VAWT version of the H-rotor that he wants to mount on chimneys. The company, Eurowind Development, issued some press releases, published some articles, tested some blades and as far as I can tell has since disappeared.
The earlier paragraph is then followed by an equally misleading statement.
“Research at Cal Tech has also shown that carefully designing wind farms using VAWTs can result in power output ten times as great as a HAWT wind farm the same size. “
This statement is true as far as it goes. An academic researcher installed 24 small VAWTs (Windspires) at a site in California. All told the “wind farm” represented 24 kW of capacity. Yes, that’s kilowatts, not megawatts. Until someone installs 24 MW of VAWTs in such a dense array, the claims in this statement are just that—unsubstantiated claims.
It’s unlikely that such an array can generate 10 times the electricity of an equivalent size conventional array. It would be quite an accomplishment if they could just equal the performance of a conventional array.
All in all the Wikipedia entry for VAWTs is limited with few citations of credible sources.
In contrast, the English Wikipedia entry for Darrieus wind turbine is an example of good expository writing. Though the use of the term “propeller” for the rotor of conventional wind turbines is incorrect, the article is otherwise accurate. There are indications in the language that the editors may not be native English speakers. Nevertheless, the article is well written and factual.
Despite the fact that Darrieus was a French aeronautical engineer, French Wikipedia’s has no separate entry for Darrieus turbines. In French, Wikipedia only has a section on vertical axis within the general entry for wind turbines.
The French version will take the viewer to an entry for Parc Éole, the site on the Gaspé peninsula where the 4 MW DAF-Indal experimental turbine was installed. The giant was still standing the last time I was there in the late 1990s or early 2000s but had become surrounded by conventional wind turbines.
No, Eole was not in operation. It has become the local tourist bureau’s “static sculpture” and tourist attraction.
As one might expect, the German Wikipedia Darrieus-Rotor entry is extensive and factual. There are several useful and informative links from the German Wikipedia entry that lead to sites not found in the English Wikipedia entries.
Disclosure: One of my books is referenced in the Literatur section of the entry and this book is cited several times in the references.
One reference on the German Wikipedia entry is to a scan of an old printed brochure produced by Sandia titled Vertical Axis Wind Turbines: The History of the DOE Program with a scan date of 22 July 2004. It’s somewhat surprising that you can find this document on the German Wikipedia page and not elsewhere.
Another reference is to a series of photos on the Heidelberger rotor. There are four of these turbines visible in these old photographs from what looks like Windtest-Kaiser-Wilhelm-Koog in Schleswig-Holstein. This H-rotor turbine used a large-ring generator that may have been an early use of permanent magnets.
One of the German references is a veritable goldmine of detailed information, photos, and graphics on nearly every imaginable form of vertical axis wind turbine ever conceived. The entry is encyclopedic and the fact that it’s in German shouldn’t deter English speakers from perusing page after page of VAWTs, new and old.
The Buch der Synergie’s Chapter on Vertikalachsen-Rotoren is one of the most extensive, if not the most extensive discussion of VAWTs found anywhere on the web. While the text is in German, anyone who wants to see if a “new” invention has been seen before should look at this site. This is truly an impressive collection of VAWT designs. Most of the text just lists details on the prototypes or promotional concepts and doesn’t delve into whether they’ve worked in the field or not. Some of the text simply repeats the claims made by the promoters of various designs. However, the extensive section on Anton Flettner alone is worth reviewing.
And if you don’t know who Anton Flettner is, and you’re interested in VAWTs, then you need to find out. He’s one of the famous VAWT inventers and developers alongside Darrieus. His rotor ships have periodically been revived over the decades, most recently by Enercon, the successful German manufacturer of wind turbines.
Another path on the German Wikipedia site leads to Heiner Dörner, a professor at the aerospace institute at the University of Stuttgart. His web pages under the tile Darrieus-Rotor is a trip down memory lane with comments on the status of various ventures and what happened to all those one-time clever designs. Dörner is someone who knows what he’s talking about. He wrote the book on Ulrich Hütter, the father of German wind energy.
In my wanderings on the internet I came across this article Aerogeneradors Darrieus in Catalan.
The Spanish Wikipedia entry for Aerogenerador has a very sketchy section on Aerogeneradores de eje vertical or VAWTs in Spanish. There wasn’t much of substance there.
In further ramblings I came across an article on Adecon in Windpower Monthly 1 April 1995 issue. There are photographs of these turbines on my web site. The article mentions that two of the four-bladed turbines installed near Pincher Creek Alberta had failed and had “toppled”. This was about the time period when I visited the site. The unsigned article said the rotors on the turbines were 30.5 m in height by 21.5 m in diameter. This is one of the few references on Adecon’s failed attempt to commercialize Darrieus turbines supported with an external space frame.