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Articles on Ducted & Shrouded Wind Turbines (DAWTs)

Like Vertical Axis Wind Turbines (VAWTs), shrouded and ducted wind turbines can be both small and large. However, they are not the mainstay of the wind industry and for that reason they are assigned a category under Small Wind Turbines on this site. Shrouded turbines are also sometimes called Diffuser-Augmented Wind Turbines (DAWTs).

There is also a collection of archival and recent photographs on the Photos section of this site. There you can find photos of Ducted Wind Turbines (DAWTs).

Man testifies he, other investors were scammed by Dragonfly in Elm Springs wind farm case

August 25, 2021,   by Ron Wood

Elser said the scam was years in the making and a working ducted wind turbine prototype was never built. Instead, Davis and Ridings misrepresented engineers' opinions about the concept to scam...

Category: Shrouded & Ducted Wind Turbines

Power Performance Test on the Ogin 2.2 Ducted Wind Turbine Prototype

May 22, 2020,   by Paul Gipe

I've received a portion of Intertek's 2016 power performance test of Ogin's Model 2.2 150-kW ducted wind turbine "over the transom" as we say. The much hyped and controversial device delivered its...[more]

Category: FloDesign-Ogin FloDesign-Ogin

The Devil Wears a Halo: Ducted Turbine Rises from the Grave

May 9, 2020,   by Paul Gipe

Flamboyant ducted wind turbine venture Ogin died a costly death in 2017, taking with it hundreds of millions in investments. The debacle tarnished the reputations of Technology Review, Arpa (DOE's...[more]

Category: FloDesign-Ogin FloDesign-Ogin

Ducted Turbines & Rooftop Mounting: Will These Ideas Ever Die? Not with DOE Doling Out Funding

May 1, 2020,   by Paul Gipe

The US Department of Energy (DOE) announced 19 November 2019 that the Distributed Wind Competitiveness Improvement Project had awarded a grant to Ducted Turbines of Potsdam, New York for nearly...[more]

Category: Shrouded & Ducted Wind Turbines, Rooftop & Urban Wind

Derelict FloDesign-Ogin Ducted Device Still Standing in Antelope Valley

April 29, 2020,   by Paul Gipe

Yep, it's still there. Derelict and long abandoned, the FloDesign-Ogin prototype ducted wind turbine is still standing in the Antelope Valley between I-5 and Lancaster and north of Hwy 138.[more]

Category: FloDesign-Ogin FloDesign-Ogin

New York Attorney General blocks WNY “wind turbine inventor” from using investor funds for personal use

April 27, 2020,  

According to the complaint, Stimm raised more than $3.5 million from 435 investors in WNY over the years, utilizing illegal sales and false and misleading statements.

Category: Shrouded & Ducted Wind Turbines

Videos of the Defunct Sheerwind-Invelox Ducted Device Still Up

January 15, 2019,   by Paul Gipe

Sheerwind-Invelox, a ducted-turbine fiasco, officially went bust in early 2018. Incredibly, there are a number of promotional videos still on line at and on vimeo. The latter is even more...[more]

Category: Sheerwind-Invelox

Video footage of FloDesign-Ogin Antelope Valley Prototype DAWT

January 15, 2019,   by Paul Gipe

While poking around on the Internet to see if anything new had popped up on some of my favorite ducted turbine projects I came across some videos of FloDesign-Ogin that I hadn't seen before.[more]

Category: FloDesign-Ogin FloDesign-Ogin

Video of SheerWind-Invelox in Iran

January 30, 2018,  

Daryoush Allaei extolling the wonders of his device in his native land. Note the location of the device--down below the ridge on which they are standing. Also notice that there are some real wind...

Category: Sheerwind-Invelox

The Nature Conservancy Clams Up on Ducted Turbine Debacle--Who Will Pay to remove it?

January 13, 2018,   by Paul Gipe

The Nature Conservancy (TNC), one of the nation's premier land preservation trusts, isn't talking about its failed investment in a ducted wind turbine debacle 1,000 miles from Hawaii.[more]

Category: Sheerwind-Invelox

FaceBook Comments on SheerWind Ducted Disaster

January 10, 2018,   by Paul Gipe

The following are comments to Another Ducted Device Dead: SheerWind-Invelox Bankrupt. They were so insightful I decided to repost them here where they are more easily archived.[more]

Category: Sheerwind-Invelox

Another Ducted Device Dead: SheerWind-Invelox Bankrupt

January 9, 2018,   by Paul Gipe

My inbox saw a flurry of emails 4 January 2018 to inform me that ducted turbine darling SheerWind-Invelox was bankrupt. While the event wasn't much of a surprise, it did take much longer than I'd...[more]

Category: Sheerwind-Invelox

SheerWind Invelox Demo Turbine in Need of Demolition

July 10, 2017,   by Paul Gipe

The Chaska, Minnesota promoter of a ducted wind turbine appears to have fallen on hard times. The fabric covering of the intake duct for their demonstration turbine is torn and in disrepair and the...[more]

Category: Sheerwind-Invelox

What went wrong with that weird wind turbine on Deer Island?

May 5, 2017,   by Scott Kirsner

Ogin raised more than $150 million in funding — even attracting the attention of former Vice President Al Gore, now a senior partner at Kleiner Perkins Caufield Byers, one of the company’s earliest...

Category: FloDesign-Ogin FloDesign-Ogin

FloDesign’s State Subsidy Up in Smoke

May 4, 2017,   by Paul Gipe

Among all those who lost money in the FloDesign-Ogin fiasco is the Commonwealth of Massachusetts. Compared to others the state lost a relatively modest amount of $3 million.[more]

Category: FloDesign-Ogin FloDesign-Ogin

Kiwi Pension Fund Loses $50 Million in Ogin Ducted Turbine Fiasco

April 21, 2017,   by Paul Gipe

New Zealand’s Superannuation Fund has written down its $47.5 million (NZ) investment in ducted turbine promoter Ogin. [more]

Category: FloDesign-Ogin FloDesign-Ogin

NZ Super Fund writes down wind turbine investment; remains committed to investing in early stage companies

April 21, 2017,  

In June 2016 the Ogin Board of Directors and management mutually agreed to separate. At that point we wrote the Fund’s NZ$47.5 million investment down to nil, and that was included in our annual...

Category: FloDesign-Ogin FloDesign-Ogin

SheerWind-Invelox--Is the End Nigh for Another Ducted Turbine?

February 23, 2017,   by Paul Gipe

Is the end near for SheerWind’s Invelox ducted wind turbine? The problems with SheerWind’s design are coming to a head as its signature clients lose faith.[more]

Category: Sheerwind-Invelox, Inventions & Questionable Wind Turbines

Clarkson Attempts Ducted Turbines—Again

January 20, 2017,   by Paul Gipe

Despite its previous association with a questionable wind turbine and its promoter, Clarkson University announced that the school in upstate New York has transferred ducted wind turbine technology...[more]

Category: Shrouded & Ducted Wind Turbines, Windtamer

FloDesign Ogin Ducted Wind Turbine at Deer Island Coming Down

November 14, 2016,   by Paul Gipe

FloDesign’s prototype ducted wind turbine on Deer Island in Boston Harbor is being removed, according the agency that operates the nearby sewage treatment plant.[more]

Category: FloDesign-Ogin, Inventions & Questionable Wind Turbines FloDesign-Ogin

Ogin Ducted Turbine Employees Speak Out

August 23, 2016,   by Paul Gipe

Former employees of the erstwhile ducted turbine manufacturer Ogin have posted comments about their jobs on a public web site.[more]

Category: FloDesign-Ogin, Inventions & Questionable Wind Turbines FloDesign-Ogin

Close-up Photos of Ogin DAWT Dismantlement in San Gorgonio Pass

August 22, 2016,   by Paul Gipe

More photos of the Ogin ducted wind turbine dismantlement have been “thrown over my transom.” These close-up photos show far more detail of the disassembly and scrapping process than before.[more]

Category: FloDesign-Ogin, Inventions & Questionable Wind Turbines FloDesign-Ogin

Ogin Ducted Turbines Removed Near Palm Springs (Updated with Photos)

August 1, 2016,  

The highly hyped ducted wind turbines near Palm Springs have been removed. The Ogin turbines were removed sometime this summer.[more]

Category: FloDesign-Ogin FloDesign-Ogin

Windtamer Ducted Wind Turbine Finally and Officially Kaput

June 24, 2016,   by Paul Gipe

It went by various incarnations, but it was founded as Windtamer by one Gerald Brock and it finally and officially is gone.[more]

Category: Windtamer

Small Vindication: Renewable Devices Swift Ducted Rooftop Turbine Gone

February 18, 2016,   by Paul Gipe

I am writing this now to close the book on this sad little turbine and the whole “let’s put them on the roof” phenomenon. Stumbling across an obscure NREL field test report from long ago (see Power...[more]

Category: Shrouded & Ducted Wind Turbines, Inventions & Questionable Wind Turbines, Rooftop & Urban Wind, Small Wind folder, Renewable Devices Swift

Ogin Installs Ducted Turbines in the San Gorgonio Pass

January 27, 2016,   by Paul Gipe

Ogin, the Massachusetts-based ducted turbine company, has installed six of seven turbines in the San Gorgonio Pass near Palm Springs, California.[more]

Category: FloDesign-Ogin, Inventions & Questionable Wind Turbines, News on Large Wind FloDesign-Ogin

FloDesign-Ogin Diffuser Augmented Turbine (DAWT) in the Wild

July 27, 2015,   by Paul Gipe

What the photos clearly show is that the prototype has abandoned the lobed mixer-ejector feature that was the hallmark of the design—and the justification for the hype that this turbine would be the...[more]

Category: FloDesign-Ogin, Inventions & Questionable Wind Turbines, News on Large Wind, News on Wind Energy FloDesign-Ogin

Sheerwind Invelox: all hype, no substance

July 8, 2014,   by Mike Barnard

Sheerwind makes radically inappropriate comparisons between their long-disproven approach to wind generation and actually useful wind generation. The numbers show that they are likely about eighteen...

Category: Shrouded & Ducted Wind Turbines, Sheerwind-Invelox

Business Day: Super DAWT investment winded by critics

February 16, 2014,   by Matt Nippert

A wind energy firms' claims it will revolutionise wind power have been questioned by critics following a US$55 million investment in it by the New Zealand Superannuation Fund.

Category: Shrouded & Ducted Wind Turbines, News on Large Wind, FloDesign-Ogin FloDesign-Ogin

FloDesign-Ogin Some Brief Comments

February 12, 2014,   by Paul Gipe

The following is an excerpt from my forthcoming book, Wind Energy for the Rest of Us. It is provided here in the public interest because of recent controversy surrounding FloDesign and...[more]

Category: Shrouded & Ducted Wind Turbines, News on Large Wind, FloDesign-Ogin, Inventions & Questionable Wind Turbines FloDesign-Ogin

Vortec 7 DAWT Summary of Test Results

January 11, 2014,   by Paul Gipe

This summary reflects my view at the time. Key participants were acknowledging the technical failure of Vortec 7, but they couched their failure in arcane technical language at arcane conferences. [more]

Category: Vortec, Inventions & Questionable Wind Turbines Vortec

Wind Cube Squarely Over the Top (Now Re-Branded as Wind Sphere)

July 8, 2013,   by Paul Gipe

Is this another example of Federal capital subsidies driving exceptionally overpriced "wind turbines"?[more]

Category: Shrouded & Ducted Wind Turbines, LEED LEED

DAWT Rebranding as Compact wind acceleration turbine

July 5, 2013,   by Paul Gipe

WARNING: There’s an attempt to rebrand Diffuser-Augmented Wind Turbines (DAWT), also known as Shrouded Wind Turbines as Compact wind acceleration turbine. Why this is so isn’t clear. It is possible...[more]

Category: Shrouded & Ducted Wind Turbines

Diffuser Augmented Wind Turbine Theory--Some Comments

July 5, 2013,   by Paul Gipe

In the past I’ve singled out what are variously called Diffuser Augmented Wind Turbines (DAWT) or Shrouded Rotors for derision. Wind turbine engineers, manufacturers of commercial wind turbines,...[more]

Category: Shrouded & Ducted Wind Turbines

SkyWolf Wind Turbines

June 28, 2013,  

Gerald Brock, the "inventor" of Windtamer is back at it with a new company using the same Windtamer design.

Category: Windtamer

Arista Power: WindTamer 4.5 GT

June 28, 2013,  

The Windtamer turbine was still being promoted on Arista Power's web site.

Category: Windtamer

Photos of Shrouded & Ducted Wind Turbines Posted

April 22, 2013,   by Paul Gipe

Ducted or shrouded wind turbines have been invented and reinvented throughout the 20th century. Ducted turbines are often wrapped in mysterious, technical babble, such as diffuser augmentation, that...

Category: Shrouded & Ducted Wind Turbines

Elena Diffuser Augmented Wind Turbine (DAWT) Update

June 28, 2011,  

Zero, Null, Nada Generation in One Year--After one full year of operation, the Elena DAWT has produced zero net electricity.

Category: Shrouded & Ducted Wind Turbines, Elena Energie

Green Investing: This is Why You Avoid Story Stocks

May 24, 2010,   by John Rubino

In retrospect, a little more skepticism would have been in order, because this is exactly the kind of thing you see constantly in hot markets. Revolutionary technology, lots of interest that will...

Category: Windtamer

Adeeb Saba assumes responsibility for product development at WindTamer Corporation

May 19, 2010,  

William A. Schmitz, Chief Executive Officer of WindTamer Corporation, said that, “The decision of the Board of Directors and me to no longer have Mr. Brock head the research and development of the...

Category: Windtamer

Elena Diffuser-Augmented Wind Turbine (DAWT)

May 7, 2010,   by Paul Gipe

Have Parisians Drunk the Kool-Aid?[more]

Category: Shrouded & Ducted Wind Turbines, Elena Energie

Windtamer Hype Needs Trimmed: Betz Beaten Yet Again Raises Questions

December 6, 2009,   by Paul Gipe

Poor Albert Betz, the German physicist must be turning over in his grave. He's been beaten yet again.[more]

Category: Shrouded & Ducted Wind Turbines, Windtamer

Ducted or Augmented Turbines--Enflo

October 12, 2009,   by Paul Gipe

Ducted or shrouded wind turbines have been invented and reinvented throughout the 20th century.[more]

Category: Shrouded & Ducted Wind Turbines

Fantasy Wind Turbines or If It's Too Good To Be True . . .

July 20, 2009,   by Paul Gipe

Scams, Frauds, & Flakes--Tell-Tale Signs[more]

Category: News on Small Wind, Inventions & Questionable Wind Turbines, Shrouded & Ducted Wind Turbines, Vortec, Sheerwind-Invelox, FloDesign-Ogin, Elena Energie, Windtamer VortecFloDesign-Ogin

Response by Paul Gipe to Dr. David Anderson Renewable Devices Swift Turbines

July 3, 2006,   by Paul Gipe

Your claims cannot be substantiated by the data made available to the public and it is likely they cannot be verified in the field. [more]

Category: Rooftop & Urban Wind, Inventions & Questionable Wind Turbines, Shrouded & Ducted Wind Turbines, Renewable Devices Swift

WPM: Vortec Energy collapses -- economics questionable

August 1, 2001,  

Doubts about an unusual approach to turbine design have been proven right with the demise of Vortec Energy, launched in 1994 with strong hopes for its diffuser augmented wind turbine (DAWT) design....

Category: Vortec Vortec

Aerodynamic analysis and monitoring of the Vortec 7 diffuser-augmented wind turbine

January 13, 2000,   by Trevor Nash

Simplified one-dimensional arguments lead to predictions of speed-ups of about 2 and power augmentations of about 4, but such power levels have not been observed to date.

Category: Vortec Vortec

NZH: Vortec hits second wind with turbine energy technology

December 7, 1999,   by YOKE HAR LEE

Vortec Energy - after spending $5 million on what its chief describes as New Zealand's most expensive "sculpture" - has emerged with new wind-harnessing technology and made its first licensing deal....

Category: Vortec Vortec

Comments on the Vortec Diffuser Augmented Turbine

July 7, 1997,   by Paul Gipe

I was critical of the development of this wind turbine for several reasons: excessive hype, questionable sales of stock, and the aggressive style of the company's promoter. [more]

Category: Shrouded & Ducted Wind Turbines, Vortec Vortec

New Zealand Sunday Star-Times: Storm over Wind Energy (Vortec 7 DAWT)

July 6, 1997,   by Daniel Riordan

AS WIND turbine generator Vortec Energy gets ready for a 10-city roadshow: to promote its $10m public offering an overseas expert has warned small investors to steer clear, saying the company's...[more]

Category: Vortec, Inventions & Questionable Wind Turbines Vortec

NZSM: Getting the Wind Up

June 1, 1997,  

Despite the questions and scepticism, hopes for the new machine remain high, with Vortec predicting that the full-scale machines will produce electricity at about 4 cents/kWhr, or about half that of...

Category: Vortec Vortec

Concentrating Windsystems - Sense or Nonsense?

May 20, 1997,   by Heiner Doerner

Since 1996 we have a "new" old, huge, new-fangled saurian, a device erected in New Zealand. . .

Category: Shrouded & Ducted Wind Turbines, Vortec Vortec

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