Will Vertical Axis Wind Ever Scale Up?

By Stephen Lacey, Podcast Producer
July 21, 2010 | 50 Comments

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New Hampshire -- Vertical-axis wind turbines have been around for thousands of years, yet we still haven't seen modern turbine producers make a dent in the wind market. Why is that so?

Most wind experts say that VAWTs are simply inferior to traditional three-bladed horizontal-axis turbines. That's why the technologies only make up one percent of the small wind market. The industry has also been historically dominated by sketchy companies and “inventors” who pushed fraudulent or under-performing technologies to unsuspecting consumers.

With today's renewed interest in renewables, consumers have forgotten about many of the past problems and are again fascinated by such machines. Just go to youtube and type in “vertical axis wind turbine” to see the dozens – if not hundreds – of technologies that folks are touting as the revolution in wind.

“There's nothing new here,” says Small-Wind Expert Ian Woofenden. “We see people coming up with the same old ideas” for harvesting wind on rooftops and within neighborhoods.

Woofenden is one of a number of wind experts who loath vertical axis technologies for both residential and utility applications. He sees them as a threat to consumer and investor confidence in wind.

However, along with what small-wind veteran Mike Bergey calls the “Bozos and Scheisters,” there are also a handful of companies in the space that are being a bit more cautious and transparent in their approach.

For example, Nevada-based Windspire Energy recently opened itself up to testing by the National Renewable Energy Laboratory. Another company, New York-based Urban Green Energy, had its power curve third party verified by China's largest wind certification body. (The company manufactures products in China). Historically, VAWT companies commonly presented theoretical power curves as “proof” of how great their technology is.

The American Wind Energy Association also set up a small wind certification council this year that will help consumers make better choices. Many of the leading VAWT companies support the move, saying that it will help filter out much of the noise in the market.

“We believe in testing. As time goes, certification will be more prevalent and we'll be right there with everyone else,” says WindSpire CEO Walt Borland.

With that said, many of the “leading” VAWT companies are tiny compared to other small wind companies. The performance of these products will determine whether or not companies move beyond experimentation and curiosity. Even the most anti-VAWT folks agree: A more rigorous testing and certification process will be good for everyone involved.

Well, good for everyone except the Bozos and Scheisters.

To hear from Ian Woofenden, WindSpire and Urban Green Energy, check out this week's podcast, linked above.

Wind Power

50 Reader Comments

Comment
1 of 50

domino316

July 21, 2010

While VWAT figures might be presented as theoretical "proof", HWAT power curves, despite a number of much larger companies being involved and more capital being spent, are as risible, given that the nameplate rating may only be achieved in 20MPH + winds, but usually far lower, a point not exactly brought to the fore when selling the idea.

Like Wave / Tidal and Ocean the VAWT companies are in the main looking to develop new ideas as opposed to the predominantly three bladed HAWT companies who are generally looking to add expensive baubles to increase costs while promoting everything but the power output.

Removing the "welfare dependency" of HAWT projects would see a drastic fall off in production and deployment and encourage innovation, as companies working on any renewable technology would have a level playing field not distorted by grants, subsidies, tax credits etc.

So perhaps VAWT will never compete with HAWT but the Horizontal lobby have no mandate to demean other technologies, by the way I work in Hydro not Wind.

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2 of 50

william-fitch-22587

July 21, 2010

Hi:

Just make it paid based on installed system performance just like SOLAR SHOULD BE, not certification based. Then all the BS goes away and the money flows into the products engineering, not certification bodies....
Regarding the cert comments at the end by Ian... it never stops amazing me how people can verbally over complicate what is simple...
If you have clear stream air available, HAWT is the answer. If turbulent air is your reality, than VAWT depending on the design my be a better choice. The tower is a huge cost of an HAWT install. VAWT's in some environments may be able do deliver a better KWH/cost end result. It is very site specific. You can not put up big towers on small land parcels, urban enviros etc... Regarding the cert tests. I think the word TRUTH was put in there somewhere. If the testing was done with all clear stream testing parameters, of course the Windspire would not do as well. Was there extensive testing done with highly directional changing winds. The truth of testing sometimes only shows the testing truth, not the engineering performance out in the real world. Certs play to markets, not engineering. The same discussion is had when looking at CAWT's. Utilities have the money to get their machines up into clear air where HAWT's perform well. That does not mean that a different technology (VAWT, CAWT, etc.) can not have good performance in environments where turbulence rules.

.....Bill

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chris-fasoldt-65380

July 21, 2010

Please excuse my ignorance but w2hat is CAWT?

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william-fitch-22587

July 21, 2010

Hi:

Sorry... should have put in the link....

http://en.wikipedia.org/wiki/Compact_wind_acceleration_turbine

It would have also helped if I did not transpose the W and A...LOL..
The W and A get switched in DAWT...

.....Bill

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JayDark

July 22, 2010

I understand that Windspire now has 600 installations -- that's great!
Another VAWT company trying to make a name for itself is Mass Megawatts Wind Power, Inc. out of Mass. They have a few million dollar contracts being fulfilled, all the while improving their technology by using a (patent pending) "wind augmenter" and "wind-prism".
To the best of my knowledge, verification testing is currently taking place to "prove" they have a competitive and viable product.
Their application, while a VAWT, is generally for commercial production as their box-like structure design can be multiplied to achieve 500kW per unit, or thereabouts. See massmegawatts.com for details. Their stock is also publicly traded OTC under MMGW.OB .

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gary-reese-20914

July 23, 2010

Thank you Bill. It is indeed site specific. Played with the VAWTs some years ago. Used a simple magnetic bearing to support the rotor. Worked ok.

GaryR

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james-scott-80525

July 23, 2010

I can only assume fraud rules supreme on this industry. Why don't manufactures provide the wind tunnel data that they have on their products? Data that shows output at wind speeds from 1 to 20+ mph. I can only assume want to hide it because none show it. That will show how many KWH are produced, allowing a performance picture. Way to much press and promotion goes into meaningless banter about "new" designs, technologies, approaches, bla bla. Show me the numbers.b It all comes down to One Simple Ratio. How much does it cost and how many KWH'$ can it produce. Why is this information not given every time a product is mentioned is beyond me, unless it makes it look like a bad deal. SS

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Anonymous

July 23, 2010

VAWT Wind turbines tradtionaly have been with poor wind speed to power generated curves. This fact has aways keep the number of people looking to VAWT's Low to none. But progress in VAWT designs and proformace in the lower wind class's has dramatically increase as is the number of calls at
worlds wind turbine sales resources company has reported this year. HAWT calls were dead in 2010 but VAWT Wind Turbine kits in USA inquires are at all time high. These turbines offer simple power of good power generated in kw at low speeds were as HAWT's of same kw value offers next to nothing for power generated with one exceptional wind turbine that features a Tilt Angle wind turbine that has been a world leader in power generated in kw rated to kwh generated in under and over 4.4 m/s Most of the callers are in lower wind class were as HAWT would never reach a reasonable pay back time.

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ferrand-stobart-81680

July 23, 2010

The HAWT industry should start looking at what the 3rd Reich Wind Energy Ministry were doing 1935-45 - contra rotation
Amongst other advantages it can remove the over turning moment of a conventional HAWT, and of course has no gearbox.
see www.grunweb.org.uk/page26.html for more recent work on contra rotation. The performance data for the machine was gleaned from a 3 month field trial in North England. Copy available
VAWT has tried contra rotation, there is a patent on it

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william-fitch-22587

July 23, 2010

Hi Again:

Allot I could say regarding some of the comments above but it has already been said before, by me and others a million times, so I am not going to repeat. Instead I would like to mention an aspect of RE power generation (solar, wind) that does NOT get emphasized enough. The flatness of the generation capacity. One of the best aspects of evacuated tube collectors is the cylindrical shape of the tubes. In the morning and late afternoon they do not suffer from large incident angle modifiers that are associated with flat glass at such angles. Consequently, there performance curve is flatter across the day. The flatness of the output, again, is a totally separate issue from the total generated capacity over the production period. Its valve is NOT seen on a spreadsheet, at least in a simple analysis or in non complex systems. A tracking PV array gives you more total energy over the day, but its greater value is that the time it produces is larger and flatter. To put it another way, if you could shift the production output of a non tracking solar device from bulging at noon to flat from morning to evening at the same total output, that from a design and resiliency perspective would be far better, even though the money generated for the day would be the same, given a totally clear day. Wind is no different. The goal of a CWAT or DAWT is to "kick up" the low end, so energy can be generated flatter over a wider set of wind conditions. They actually do work and do that. They suffer a cost issue do to the necessary strength of the structure to accomplish this, costing more than the increased power output. The dollar rules, so the better engineering design never makes mass production and does not proliferate. A VAWT also endeavors to produce better at low end and in turbulent conditions, increasing the possible locations for wind energy generation. After all, some is better than none... and allot of somes can add up to allot!!

.....Bill

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guy-mercer-166601

July 23, 2010

HAWTs are near the limit of capacity, while VAWTs are only at the start of their potential. If the airfoil is fixed the angle of attack and the relative wind velocity varies too much as the airfoils rotate about the system's centre for a VAWT to be efficient. Allowing the airfoils to move in a controlled manner like a sail boat going in a circle opens a whole new range of potentials.
Vertical wings can move and be stayed enabling very tall stuctures.
The diameter need not be resticted if the mass of the system is not supported by the central bearing. There are many ways of supporting the mass. Extreme diameters equate to extreme mass and great flywheel energy storage capability. Multiple wings on extreme dameters also enables air velocity recovery prior to reaching the leeward airfoils enabling increased energy harvesting.
At current engineering limits the potential capacity of a super VAWT is arround 750 Mega Watts per unit. The tangential velocity can be kept much lower than the tip speed of HAWT minimizing noise, ice throw, and environmental risks.
It enables a massive scale / capacity jump with the benefit of much lower land area requirements, with inherent energy storage capability for more stable supplies.
Guy

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Anonymous

July 23, 2010

Mike Bergey would not have any vested interests now would he? Lumping everyone into the same box.

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ferrand-stobart-81680

July 23, 2010

To william-fitch-22587
There is a "forgotten" Solar Thermal technology which combines tubular heat collectors [non vacuum but "enhanced"] plus auto tracking with fixed geometry.
Invented by an English lady about 1957, fully tested by Harold Woodward at Woolwich Poly about 1958 and then forgotten
Have a project in hand to revive it in a PVT format.

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PVinstaller

July 23, 2010

What is really the bottom line is the amount of power ( in Kwh) produced to the 10-year cost of the turbine - a modification of a previous post. By this measure, I'd put up one of Mike Bergey's little 1 kw turbines against ANY vertical "marketing dream". It would still far outperform them on a turbulant roof top in any city. Period. It's just physics folks.
I haven't seen ONE vertical physically survive three years yet. Of course, all 24 of them that I've tracked over this time (except Windspire) has gone bankrupt or is out of business within three years so it's a moot point really. Windspire is on their 4th or 5th generation of machines as well (ask them about their previous designs sometime...)
All of you non-physics/mechanical engineer can keep dreaming that these vertical wind machines somehow will become realities (maybe at the same time as space travel at warp ten becomes reality?).

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william-fitch-22587

July 23, 2010

Hi:

"All of you non-physics/mechanical engineer can keep dreaming...."

You don't say.... all lumped together are we... soooo tempting, but I won't...
BTW... all concrete realities start with a dream... and purest engineers don't talk about dollars and marketing to bellwether design, they talk about engineering and leave the dollars to the marketing and sales people...
...you need to increase the acceptance angle on your blinders...

.....Bill

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Buck

July 23, 2010

Dear Bill-fitch;

You can put up towers on small urban lots. Its people like you and the AWEA conceived Idea about it that keep it from happening, residential wind that is. Just another restrictive limit that has been eclipsed by more modern products. Buck Shaw

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william-fitch-22587

July 23, 2010

Hi:

...like me and the AWEA!!! .. you have NO idea how funny that statement is..LMAO!!
...but just to entertain, lets say I have a 1/4 acre lot ~100' x 100' and I decide to put up a 5K on a 75' tower, not to high really or unusual...
I put it dead center, max distance from all boundaries. SO, its OK if when it falls over if it lands on the street or anyone of my three neighbors properties..??... maybe when they are standing watering their lawn...

.....Bill

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Windmillman

July 24, 2010

It's the responsibility of every industry to police itself. Bad technology being pawned of on a gullible public damages honest consumers and legitimate manufacturers and reduces the amount of R&D funding a legitimate manufacturer can spend on advancing proven technology. For any clown out there that thinks horizontal axis manufacturers are attacking vertical axis manufacturers because they have a vested interest in horizontal axis, you need to wake up and realize that we would be making vertical axis if they were any good. Ive been looking for 40 years and I haven't seen one yet. We have been in this industry a long time and have seen many company's come and go and the most short lived of them all are vertical axis. The problems are fundamental and unless you can change the fundamental operation of a VW wind turbine. the only way to do this is to turn it on its side and rotate the blades outward 90deg. Oh wait, now you have a turbine built the way it should be built - operating on the horizontal axis. My hats off to Mike Bergey for calling it like it is "Bozos and Scheisters". It's time to stop reinventing square wheels and calling it something new.

Tom Conlon

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domino316

July 24, 2010

thomas-conlon - So by that measure would anyone raising legitimate questions be, as you succinctly put it, a "clown", just the same way the Nuclear lobby would have a "vested interest" in promoting their technology over Gas, so would the HAWT sector over VAWT (or even Solar), VAWT is never likely to exceed HAWT, given that the Horizontal turbines can be so much larger, hardly likely that any VAWT is going to be a 400ft tall, 350 ton monster built on 30ft square cement and steel rebar dotting the landscape, but on a like for like basis in certain scenarios a design one day may do.

As to R & D funding, there would be lots more available to other technologies if it wasn't being sucked up from Feed-in Tariffs, Federal Incentives, Grants and a myriad of other "welfare payments" made for Wind (and some Solar), how many of these large Wind Farms would have been built if there weren't "federal bribes" to do so, even the large operators have said that.

As to the comment regarding industry policing itself and bad technology being pawned off on a gullible public, nothing highlights that more than the current wind industry, and by that I don't mean the ones who sell a time proven product, I refer to the "city slickers" who jump on the bandwagon and then promise all things to all people, only to sell a dud and then move on to the new fad.

The downside for people in the business a long time will be having to disassociate themselves from these "fly by nights" with sceptical consumers caught out by them and point out that "windmills" have been around hundreds of years and can still fulfil a purpose, making life harder for people who knew what they could do and what they could deliver and sold them credibly on that basis.

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Buck

July 25, 2010

So are you for or against residential wind power. Oh, forgive me, your against Towers. Come to think of it I see Towers fall over every day. After all there are no regulations on engineering towers.. Right. Oh well, forget it. Your right. Stupid Idea residential wind. Energy independent homes. Off the grid. What ever eh boys....

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william-fitch-22587

July 25, 2010

Hi:

I am for energy independence whether it is solar, wind, hydro, etc.. more than you will ever know. I am for innovation and invention, creativity and most importantly TRUTH. BUT, you can not allow energy creation "devices" to run wild without some form of guidance where there is any sort of population density, any more than any other "thing" that one might build. Regulation for the sake of regulation...NO. Hell NO. But you have to have some reasonable engineering guidelines.
As a far reaching side note, you might consider the unpleasant fact that, "Freedom is inversely proportional to population".
Just a philosophical thought.....

.....Bill

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mitch3

July 26, 2010

Doesn't location application dictate design? I've watched some helical turbines that seem to work very well in a location that defies tall towers because of at least two reasons; one the NIMBYISM forbids anything that can be seen and two the wind is moving UP a 1900 foot slope hard enough to bend the trees back. For most of the day not night the wind does this and then dies off at night. I don't know the out put but they seem to work quite well.

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NewWay

July 27, 2010

The academic literature on the debate between HAWT and VAWT is clear, HAWT are more efficient then VAWT. The difference is greater between impulse based VAWT then aerodynamic VAWT. For a peer reviewed summery of the literature see; http://www.2004ewec.info/files/23_1400_jeanlucmenet_01.pdf. The design of HAWT and VAWT are both ancient. The impulse based VAWT is still the most popular for pumping water in third world countries because it is cheap to build and reliable. The aerodynamic HAWT is more efficient and has proven the best choice for utility scale terrestrial-based wind power generation.

America's best wind resources are 30 miles off our Coasts and over the Great Lakes, this wind resource is conveniently located near to 75% of our major load centers. We need floating wind turbines. Perimeter supported VAWT would have a wide base and a low center of mass, conveniently allowing for flotation. They could be built in our old shipbuilding ports or cargo transfer ports, towed out to sea, anchored in a mooring field and plugged in. No seafloor foundations or assembly at sea required. Ocean only transportation, slow rotation speed and a stable two to one aspect ratio means the VAWT can be scaled up much larger than a horizontal axis turbine. Everything above the base ring can be built with sailboat mast and bicycle spoke technology to create a lightweight, stiff and inexpensive cylindrical shape. Offshore winds are class 6 which have twice the energy as the class 3 and 4 winds over the Midwest. This easily makes up for the %50 lower efficiency of the VAWT and on top of that offers a dramatically improved capacity factor. The high solidity and low rotation speed of the VAWT does not chew up birds or bats, 30 miles offshore would be beyond the horizon and so beyond NIMBYs and state courts. A big picture, smart grid, objective look should consider all of the issues and constraints involved, not just the turbines efficiency.
Drew, New Way Air Bearings

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william-fitch-22587

July 28, 2010

Hi:

Just out of curiosity, do you know how many different grid service providers control the GL perimeter..??.. It would seem that the three largest lakes would allow at least 30 miles from all shore points...
http://www.epa.gov/greatlakes/factsheet.html

.....Bill

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rich-barbarics-33637

July 29, 2010

I've seen 2 small HAWTs in action in NJ. The first at a farm is in a wind dead zone in central NJ but pushed by the State incentives a number of years ago(per the buyer comment). The wind resource was misjudged and even though on a 100' tower, the project will never pay off. The second is at a muni utility in south Jersey on a 60' tower. It too will never pay for itself and, in fact, sends a misleading message to citizens who might respect that utility. If the wind resource doesn't exist on a given site, no windmill makes sense. Where wind does exist, there are variable performers. I don't always need the most efficient device. For those that say never to VAWT, I'd only say never say never. I'm a physics major, and while respecting the wise men, understand there are unexpected outcomes that surprise even those guys, from time to time.

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david-cooke-34064

July 29, 2010

There seems to be a mystery about why vertical axis turbines are not catching on but I think it's simple. Two reasons. They are never or rarely sited on 75ft towers and so do not perform well with all the turbulence near the ground and the buildings (read obstacles and turbulence generators) they sit on. There is no laminar flow but rather "incoherent" flow where the available energy is coming from all over. Note: when energy comes from two directions at once they are not additive. The resultant vector is less than their sum. Second the energy that does transfer to the blades usually passes though the device and exists as self-generated turbulence on the back side of the retreating blades. The ideal angle of attack for energy transfer is constantly NOT ideal. No matter how hard you try this inherent inefficiency cannot out perform a horizontal axis machine operating in laminar flow.

The HAWT air flow transfers energy once and departs the blade as turbulence that can and longer impact the performance of the machine unless there are other objects close behind it. This is not to say that VWAT don't work. There are many creative designs coming out . . some quite beautiful and innovative designs but one cannot expect any of them to outperform HWAT for the same cross section. It's watts/square meter. There is only much energy IN the wind and extracting it from laminar flow once and letting it dissipate behind the device without having to deal with the turbulence created by the device itself will always capture more of it.

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william-fitch-22587

July 29, 2010

Hi:
The resultant vector is short of the sum (friction) but is substantially greater than either of the two or more contributors. An HAWT must face "into" the wind to be effective. A VAWT has no preference. We have a Skystream dealer down the road. The SkyStream 3.7 is an HAWT 12' three blade rotor, 2KW alternator, etc.. designed as a "plug & play" device. It is mounted on a 40' poll out in front of the business. The location is along a three lane road, flat with gas stations, fast food etc.. The Sheetz station has a big flag on a pole about 75 to 100 yards from the SkyStream. Both are about the same height. I drive by that location maybe once a day. It is surprising how many times I notice the turbine not spinning but the flag is pretty much out straight. The wind is blowing in the 7 to 10 range, and the turbine would easily be turning if it was facing right. When the wind "catches" it at 90 or 180 Degs to head on, there is insufficient drag to rotate the gen into the wind, so it sits until enough of a gust hits it and gets it to turn into the wind. If the wind is changing allot, it will spend a great deal of the time seeking the proper wind direction, rather than producing optimal energy. This is the major advantage of a VAWT. It does not have to seek or even only be impacted by wind from a single direction. No matter where the wind is coming from, it will spin immediately. The trick is to design VAWTs that utilize drag and lift in their design to help push up the over all efficiency. VAWT Wind Mfgs should not make outrageous claims about their machines any more that an HAWT dealer should say their machine will pay for itself in what is really a no wind location. Lying is lying no matter how you try and cloak it, whether you are wealthy and powerful or poor and without means. VAWTs have locations where their total energy and physical benefits can make them a preferable solution. Mfgs should concentrate on identifying those attributes, clearly and correctly.

Bill

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Don

July 29, 2010

Stephen!
I can't believe you disparage inventors, without whom, none of us have a job!

Seriously now, I think the quotes were intended to identify the so-called "crackpots" who claim to be inventors, but this is a pretty gray area. So many of today's technologies are the products of those who think WAY outside the box. Tesla is the classic example. Arguably working in the fringe much of the time, our AC power system is his baby. Our inventors group, Inventors Association of CT, like dozens of others, helps provide everyone, without regard for their field or "technology", with the tools for protection and commercialization. None of us really know where the "next big thing" will come from, especially in renewables. The market will usually sort out the quackery, right?

Vertical axis wind turbines are an interesting case. My personal problem with them is simple; how can a device with a substantial portion of its working surface moving INTO the wind, compete with HAWTs, where all surfaces are doing work? I get that some VAWTs fold back forward-moving surfaces or are shaped to reduce drag on the non-working face and have proportionately larger working surfaces, but ALL surfaces of a HAWT do work. I also get that there are advantages based on profile, local building codes and interference, but can anyone address the question I pose?
Don

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christopher-lee-166032

July 29, 2010

Several commentators hint at the fact that as wind (and other renewables) are thinly spread, generators have to be close to the point of use, where compromises are necessary. For wind, we need devices that move at a safe speed and work at low irregular wind speeds. That means big, like your garden fence or a huge wheel fastened to a gable end, or the building itself. Mechanical efficiency and windspeed^3 must be considered, but even a few hundred watts are worth having if the price is right.

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domino316

July 29, 2010

Don
A very pertinent point you make, I think a lot of people don't grasp that it is from inventors that industries can be made and jobs created, expanding that if it wasn't for the Wright Brothers there would be no aeroplanes or airports all the way back to the support industries like in-flight catering, just like without the invention of the internal combustion engine there would be no local "auto-repair" shops, in fact just taking Automobiles, Air and the Railways as examples, the ancilliary industries from them is vast, if you added Baird (TV) and Bell (Telephone) and all the spin-offs (either products or services) from their inventions, supporting inventors should be a primary concern, and yes there will be some "crackpot" ideas, just like there will be others who have convinced themselves their invention is the "bees knees", while there will also be others who may just find the next big thing, and I would add that people who disparage inventors might like to know its not exactly fun e.g. waking up at 4am booting up a PC to research some miniscule fact or wandering around the store grabbing groceries while kinetic energy equations whirr around in your head.

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robert-henry-168267

July 29, 2010

I will never understand the position of these articles. How much does it cost per KW per year? Until it is less expensive its just talk.
A certain windpower device costs X amount. There are world wind maps which tell you how much wind per year. In these areas, how many KWs do these devices produce in a year? UNDERSTAND? Cost. KWs.

Pretending there are other issues more important than that is delusional.

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william-fitch-22587

July 29, 2010

WOW!! Now that's that's what I call tunnel vision.
The dollar only matters... I am in the desert, would I rather have 20 dollars or 20 dollars worth of bottled water... Humm... tough choice....

.....Bill

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jajagabor

July 29, 2010

I can confirm that putting up high towers can be prohibited by local law. The College of the Atlantic, based in Bar Harbor, Maine, erected a HAWT in nearby Beech Hill Farm (about 20 miles or so from Bar Harbor), but were limited by the local law from erecting it over 40 feet in height, which (of course) has severely limited its performance (this is all near the Atlantic coast, of course, so wind speed on average is good). Yet, in nearby Southwest Harbor (nearer to this turbine than Bar Harbor), there is no height restriction, according to my girlfriend who lives there.

This goes to show that even within a few miles, laws that determine how high a tower can be can vary tremendously.

Of course, as someone on this board pointed out, the tower itself for HAWTs seems to be the most expensive and/or legal thorn. So the main question is, can VAWTs perform in areas where high towers are either restricted more cheaply and with comparable cost effectiveness as other forms of alternative energy?

Windspire and Urban Green both have the right idea in getting their products tested since it will at least give the public SOME idea. Trying to simple, straightforward comparisons (side by side, same general cost involved) from ANYONE has been like trying to pull teeth out so far. If only magazines like HOMEPOWER has HUGE budgets and personel and thus could erect and test each and every machine, just like auto magazines have had data on car performance for years (skid pad g force data, zero to whatever acceleration data, braking distance feet etc. etc. etc.). (Car magazines, though, usually get the cars they test free from the manufacturers though . . . )

Another query, though it is unrelated to wind power, is this: when are lithium batteries going to be available for charging via alternative energy? The water cooled technology that is used in the Tesla seems like a nice way to prevent overheating and fires - and why isn't this being talked about anywhere?

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ferrand-stobart-81680

July 29, 2010

Who invented aircraft ?? Wright Brothers may have made an early powered flight but Monk Eilmer flew a glider in 1020, as did Sir George Caley's coachman about 1850.
Seriously re VAWT the point about the rotors going "against the wind" half the time mentioned above was made about 1860,

The 3rd Reich Wiud Energy Ministry work - based on proposals by a friend of Betz, STILL have not been fully examined as a potential source of cost reductions and aerodynamic improvements.

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william-fitch-22587

July 29, 2010

Hi:

http://www.altenergymag.com/emagazine.php?issue_number=07.04.01&article=contra

I believe this is yours..??.. Very interesting.....
What gets "picked" VS what gets left behind usually has NOT to do with engineering, but with vested interests...
Again, most interesting...

.....Bill

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Howellt1

July 29, 2010

Straight up - as current technology stands and ignoring some rare case where special design is required - HAWT is the economical and technologically superior product (under stand that you can't always compare technological and economical advantages together as Bill has alluded to). As someone who has worked for a utility company, VAWT technology is not practical. In cases where wind may be turbulent enough such that VAWT would be a more suitable technology and HAWT would be unable to utilise the wind shear effectively, the site itself is not economical to develop. Now i speak from the pure standpoint of developing a "wind farm" for 50+ MW generation and not installing individual or a few units for a "specialised" purpose.

The advantages VAWTs have going for them is the design of the shaft and connection to the generator. There is no need to transfer power into different axial planes (improved efficiency), and there is no need to mount a hefty 30+ tonne generator and nacelle (all up typically 50-60+ tonnes for large industrial turbines) in the air (expensive). Overall they are much cheaper to install. Unfortunately, that's where the benefits end and the overall aerodynamic efficiency just can't compete on a commercial scale. It doesn't take long (relatively) in the life of a utility for a HAWT to surpass the VAWT commercially. We speak about improving technology and aerodynamic effiency, but there's only so far one can go to fight physics.

Remember, the wind has more power to harness 80-100 metres up in the air. VAWT or not, you want your turbine up there to optimise output and even with a VAWT, that means putting it on a tall, expensive mast.

This is just a small snippet of my experience.

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Anonymous

July 29, 2010

I agree with comments 25 & 26. Please read them yourself, they are on topic and correct.

Wondering what happened to that certain VAWT during testing that was mentioned in the podcast?

http://www.nrel.gov/wind/smallwind/pdfs/mariah_report.pdf

VAWT's are good for marketing, but they give a false image of good sustainable energy. Put one on the roof of your business and it will attract people. But don't bother putting a generator on it, just let it free spin. No utility hook up fees, no electrician permits, no municipal approvals, just a fancy spinning sign.

There will be a good VAWT one day, but it will be high on a tower, away from listening ears, and well reinforced... And it will be more expensive then an equivalent HAWT.

Now go read the linked report and have a laugh!

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william-fitch-22587

July 30, 2010

Hi:

Read the report from top to bottom. Did not find anything funny. I would classify it as a Beta unit, and myself, would not have spent the money for third party testing at that stage of the products development.
If my detection of "mockery" in your comment is correct, all you are doing is showing your lack of experience and awareness in product development and the normal "going's on" that occur when anything new is engineered and tested.
Have a nice day...

.....Bill

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william-fitch-22587

July 30, 2010

Hi Once more:

http://www.treehugger.com/files/2010/07/900-foot-offshore-wind-turbine-mimics-spinning-sycamore-seeds-video.php

Another off shoot of VAWT...
ALLOW NO INVENTION, ALLOW NO CREATIVITY, ALLOW NOTHING NEW... this type of thing cannot be tolerated... we must keep to the status quo... if its not a 10K Bergey, it cannot work...LOL!!!

.....Bill

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Anonymous

July 30, 2010

Bill, no, you are wrong about my experience.

And to everybody reading, Bill is correct about the testing being done too early. It is the push to market that prohibits some turbine systems from succeeding. Five years of field testing involving multiple revisions is too long for private investors and venture capitalists. They want to see a product sold asap, and that's why we see so many problems and miss represented data. The quickly achievable power data is from theoretical, low budget moving truck testing, or maybe wind tunnel testing. Each of which does not accurately depict the real instal with turbulent wind, varying wind speed, and roof or pole mounting.

So when you buy your fresh on the market micro VAWT or HAWT, YOU are actually providing the test data, and the funds for R&D, for the company. "Buyer beware", right?

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william-fitch-22587

July 31, 2010

Hi Anon:

You are 100% correct about that...
Business is Engineering's worst enemy, whether it be wind turbines or software or anything else for that matter. It invites lies in place of truth.
Which is why from a philosophical perspective I feel that, "A world based on currency is not sustainable for the long haul".
But, at least business cannot stop the sun from shinning, the wind from blowing or any other RE source from being present for harvesting....
..so maybe, there in, radiates a weak glimmer of hope...

.....Bill

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Fez

August 7, 2010

I'm a huge fan of VAWTs for domestic and urban power production but acknowledge that in steady wind there is no comparison, HAWTS will perform better. This is easily shown by wind tunnel testing. However there is yet to be a test procedure for turbulent wind so the tests are not like for like. A long term test in comparable sites would be the only way to compare pairs of different turbines. Even then you would need to constantly monitor and compare the wind speeds for each turbine. A time consuming and therefore expensive procedure that makes it unprofitable.

All the graphs on the bettergeneration site whose link was supplied by Clee, are all from the manufacturere own figures so do not represent much more than a wish list. Many turbines, both small domestic versions or large tower based have shown that their performance has often fallen well below their stated output. The site does have a comprehensive list of manufacturers but is mainly promoting the 'Power Predictor", a dedicted weather station.

Can any one explain the falling graphs after a certain speed for VAWTS. I know that in high winds HAWTS have to be shut down or locked up to prevent over spinning but had thought that VAWTS simply dump the extra wind if it exceeds its maximum working speed?

The comment about the half the blades of a VAWTS always travelling against the wind for half each revolution was, I thought, why they didn't need to be shut down in high winds. The blades travelling directly away could never travel faster than the wind. The angle of attack of HAWT blades enables them to travel faster than the wind as they 'tack' across the flow.
It is the enormous gyroscopic effect of spinning HAWTs blades that prevents them to be re-aligned quickly to cath the 70% of the wind that blows off the prevailing direction. I believe it is often the mechanics trying to twist the blades into the wind that causes large towers to collapse.

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Fez

August 7, 2010

What is the convention for stating the size of the any turbine? Is it the swept area of the blades which, for HAWTs, would be the area of the circle described by the tip of one blade multiplied by the number of blades and for VAWTs would be the curved surface area of the cylinder described by its blades, again multipiled by the number of blades but then halved because half will have been sheltered from the wind by the other half. OR is it the area of the profile that each turbine offers to the wind, ie a flat elevation of the static blades that are hit by the prevailing wind?

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william-fitch-22587

August 8, 2010

Hi Fez:

"The blades traveling directly away could never travel faster than the wind...."

Not true.
Non loaded VAWT's with a lift "element" designed in, can have a TSR as high as 4. That is, four times faster than the wind velocity. It all comes down to the design as to how much of it is drag VS lift.
And I agree, there is a huge potential for VAWT's in areas where an HAWT is not desirable or possible. But, the minute you say anything positive a VAWT design, the tunnel vision HAWT people start talking about which gives more energy, etc., etc.. completely missing the point.. of possible at a site VS not possible at a site...
But as EVERYTHING in our world, its all about who has the money interests... Look at the nothing short of incredible potential of solar thermal!! It is staggering, but, where is all the Buzz in the USA and consequently all the purchases, PV...
The technology has been available for the past 40 years to have us at a point today that 25% or more of our thermal energy use could be solar. I think the current stat is less than 1%...
The only green in the green movement is money.... except for true environmentalists...

.....Bill

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sunnyman2001

August 10, 2010

Hello All, my first post, I hope you find it reasonable. While there is no question that HAWT's are more efficient than VAWT's, it is difficult to imagine a future of hundreds or thousands of small HAWT's spinning over the suburbs or cities of the world. As a long-time researcher into renewable energy applications for the urban setting (Cleveland, Ohio), I have studied HAWT's & VAWT's for suitability in that setting. The engineering challenges of locating ANY moving generator on an occupied structure are great, but not insurmountable. The visual impact of many spinning propellers on towers to get to laminar-flow wind may be "beautiful" to some, but probably unacceptable to most. My research has centered on the premise that to gain wide acceptance in an urban environment, spinning wind turbines should have a minimal visual impact. VAWT's offer the opportunity to be constructed in a "cage", which could be tricked-out to hide the operation of the turbine. The "cage" could look like a church bell tower(horizontal slats) or an open-mesh screen (chimney-like) and mounted at the roof peak. Yes, the "blind" will reduce the wind availability, but eliminate the visual "pollution". Yes, the blind reduces wind availability, but can act as a re-inforcing stability structural element for the turbine, and, properly designed, may augment the low speed/turbulent airflow at roof peak. High-efficiency is not the only consideration for technology. Long-term reliability, ease of maintenance (generator in the attic), and ACCEPTANCE (invisibility) are very important for widespread usage. VAWT's may also be built into the edges of high-rise buildings, and "blinded visually", where higher speed winds (yes, turbulent) are available. The engineering challenges include vibration elimination, and silent operation. I am NOT a VAWT fanatic,but a dedicated renewable engineer looking at the broader picture of integrating all renewables into urban life. BIPV may be the best option. Mike

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mitch3

August 10, 2010

sunnyman

You brought up a point that requires an answer; why are all wind turbines painted white or polished metal? Has anyone ever seen a wind farm painted so that it blends into its background like a stealth bomber? Just wondering if there was a reason for this phenomenon.

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ferrand-stobart-81680

August 10, 2010

Until recently there were VAWTs of quite large size in certain Middle East countries including Afghanistan. They differed from mots modern ones in that the "reverse" rotation was shielded and the wind entered through a comparatively narrow slot to strike the carpets which were the usual "blades" material.There are some illustrations about I think. The slot direction was fixed, as there were "fixed direction" winds in the mountains. Air exited though the top of the windmill.
A modern version of this, albeit so far on a small scale, can be seen here
http://www.peswiki.com/index.php/Directory:Ettridge_Wind_Turbine#Apr._13.2C_2010
http://www.ettridgewindturbine.com/

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hwd007

August 17, 2010

But do they ( VAWTs ) scale up to megawatt class ? What is the worlds most powerful commercial VAWT ?

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redeldorado

September 18, 2010

Hello from a newbie...I've got a patent pending on a new approach to developing a large scale (40-50 ft. blade length) VAWT. I'm in search of some engineering feedback as to why I shouldn't be excited about my design. I'm in the San Diego area. I've included a YouTube link showing my homemade (1/10th scale) prototype in action. I was pleased with it's performance during a recent trip to the desert, where wind speeds were fluctuating from 5-35 mph.
Standing by for any input...

http://www.youtube.com/watch?v=hEkVrfMHGl0

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ferrand-stobart-81680

September 19, 2010

Iranian windmills date back to 2,800 years ago, various items about this here, just in case anyone is "re-inventing the wheel" !!
http://www.ullesthorpewindmill.org.uk/index.php?act=viewDoc&docId=7

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V4S-4TY8W57-1&_user=10&_coverDate=05%2F31%2F2009&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1465992484&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ad7d33c0bc51465d2573eb31ea7a6cd7&searchtype=a

http://overleafundertree.blogspot.com/2009_07_01_archive.html

http://www.diamondwindsolutions.com/wind_turbines.html

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Stephen Lacey

About: I am a reporter with ClimateProgress.org, a blog published by the Center for American Progress. I am former editor and producer for RenewableEnergyWorld.com, wh... more »