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Vertical Axis Wind Turbine With Push and Pull
Sterling D. Allan writes "After 10 years of prototyping, wind tunnel testing, patenting, and tweaking, Ron Taylor of Cheyenne (windy) Wyoming is ready to take his vertical axis wind turbine into commercial production. Design creates pull on the back side contributing to 40%+ wind conversion efficiencies. Because it spins at wind speed, it doesn't kill birds, and it runs more quietly. It also doesn't need to be installed as high, and it can withstand significantly higher winds (can generate in winds up to 70 mph, compared to ~54 mph tops for propeller designs). Generating costs estimated at 2.5 cents per kilowatt-hour, putting it in the lead pocket-book-wise not just of wind and solar, but of conventional power as well. Production prototype completion expected in 5-7 months."
...but I don't take anything "Open Source Energy News" posts seriously anymore. It seems like every post that comes from them is a crackpot.
While vertical axis wind generators aren't new - the Soviets utilized vertical designs for the most part - this design is. Wind power usually isn't practical or environmental for large-scale deployment (land usage/kW is too high), and I expect this design won't change that, but it could make wind an even better choice for microgrids.
Shame the article reads like Yet Another Slashvertisment (someone wants venture capital I guess) - I'd like some more details.
Birds don't move at wind speed. Sounds like a recipe for a collision!
Another obvious advantage of this design is that unlike a propeller, you don't have to turn them around when the direction of the wind changes...
A couple of years ago I talked with an engineer friend about this when we got on the subject of alternative energy. This isn't a new idea of course, variations have been used above chimneys for a long time for instance. He told me then about the large number of advantages to this design. I don't remember if I asked him the question that pops up in my head now - why did the propeller design become the norm?
Being bitter is drinking poison and hoping someone else will die
Ron Taylor of Cheyenne (windy) Wyoming is ready to take his vertical axis wind turbine into commercial production......Production prototype completion expected in 5-7 months.
Now being the old fuddy duddy I am (at the tender age of 21) I'm obviously using an old and outdated definition for "ready for commercial production." See, the definition I'm using is one where the prototyping stage is over, and these things are being made in some factory and are about to be sold to companies/people. Now obviously not being up-to-date with the latest definitions, I was quite excited when I read it was ready, only to have my hopes dashed by the end of the summary.
Why don't you call us old-timers when you actually have a commercial product?
No, this guy is not full of hot air. He's not all bluster.
The technology does blow everything else away.
Yes, it will succeed, and not just in vertical markets.
It really took some gust to work on this.
----
Now I have to go back to bed in a fit of self-loathing.
Raise your children as if you were teaching them to raise your grandchildren, because you are.
The entire device looks like a solid structure to passing birds, hence they fly around it. Birds don't fly into solid walls.
This is unlike conventional wind turbines that chop through air too quickly for birds to see them.
You haven't RTFA have you? No, of course not, this is Slashdot after all.
From: http://www.windside.com/
"Windside works, when others don't, with gentle summer breeze and in a violent winter storm. It works, when others are in deep frost. Windside produces electricity at least 50 % more in a year than traditional propeller models. All the year round. Many things make it extraordinary. And therefore it gives the best value for the money."
Not sure what the differences might be. Winside apparently has been producing these vertical axis windmills for extreme environments for, they say, about twenty years. But they do seem costly. They use a helix type design for the blades, see: http://www.windside.com/products.html
A 21st century issue: the irony of technologies of abundance in the hands of those still thinking in terms of scarcity.
Yes, and even worse, it uses up the wind.
And it's all... horseshit.
/. crowd, by pulling us all in to wow at the latest, greatest power generation technique that's going to revolutionize our world.
5 58, or http://www.windstuffnow.com/main/vawt.htm.
What he's proposing is a Savonius windmill. A fancy aenometer. Which we already do much, much better with the Darrius approach. The maximum possible energy that we can get out of the wind is 59%. Savonius windmills are far, far less efficient, as they rely on drag, and not lift.
Of course, he claims that it works off of lift, which-- if his mill even exists in reality-- it probably does, but the fact that it only gets "a little" boost from lift means that it is almost completely drag based.
One problem that people have when visualizing a windmill is the question, "Why not do it like a paddle-wheel? Like on an old steam-boat?" Well, do you still see those old steam-boats tooling up the river and across the ocean. No? Maybe you should wondered why. It's because... surprise, surprise, it's less efficient.
Not to mention the ridiculous claims about hurricane/tornado proof design. And the centripital forces it's have to undergo at these speeds. (Real VAWTs tend to be able to spin at such high speeds that they are explosively dangerous.) And the torque exerted on the bearing coupling of a several story high building when there's 150mph of wind pressing on the top.
opensourceenergy.com seems to be nothing more than a shrewd attempt to make fun of the
For some real information on VAWTs, check out otherpower.com. For instance, http://www.fieldlines.com/story/2005/10/7/63930/5
www.eissq.com/BandP.html Ball and Plate System. Amuse your friends. Crush your enemies.
if the downwind blade is travelling at windspeed, it is generating no force (and admittedly killing no birds who are flying with the wind, ie balloons). But, that implies that the upwind blade is travelling at twice the windspeed, relative to the wind.
So that little argument is rubbish.
Actually, the whole article is not too bad overall, we certainly see worse in real papers (eg the Guardian's coverage of that hydrogen atom fraud).
That is because airospace engineers are the main designers of these kind of machines. They know propellers, have all the systems to calculate what is possible with it, and through old designs of windmills (from 1400AD or even earlier) the principles pretty much stayed the same.
My wife's sketchblog Blob[p]: Gastrono-me
I'll be honest, I really have to wonder about the whole windmills-killing-birds business. It always gets dragged up, but does anyone really know how many birds those propellers actually kill? I'm willing to bet it's very low; I also suspect way more birds are killed by flying into vehicles on the highway, or into the sides of highrise buildings (I had one kamikaze into my house last week, and that's not even a high rise).
The whole bird thing sounds like a convenient excuse invented by people who really oppose windmills because of noise or land use issues, but want a fuzzier, more PR-friendly excuse. The kill zone on a windmill is basically going to be the circle described by the rotor tips as they go through the air, so it's not a huge zone (as you get towards the center they're not moving as fast, tangentially) and at any given time it's not as if just flying into that ring would result in death, you'd have to be at a point at the particular moment in time when the blade moved through it. Last time I checked, birds don't hover, so you have two moving objects that would have to compete against some long odds to end up in the same place at the same time. Also, the turbines are noisy as hell -- something which is a legitimate criticism -- and I find it hard to imagine that birds wouldn't be scared off by the sound, air currents, and motion. (Actually they wouldn't make a bad large-scale scarecrow over farmland...)
Call me overly cynical but I find that particular objection dubious.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Maybe I could adjust rotating doors in shops to this design. Than it can power the lights or something like that. With enough wind, people will get sweeped into the store by this system too.
My wife's sketchblog Blob[p]: Gastrono-me
Anyone Remeber the Cousteau Turbo Sail, same principal.
Everything old is new again ? or just a case of two people reaching the same conclusion through trial and error.
If not this particular company and technology, the prices they are giving are in line with most analysts' expectations.
Like a lot of other technologies, this one is going down in price in a predictable way. Check out the wind energy data at earth-policy.org, especially that last figure.
The sector has recently been experiencing Hockey-stick growth in investment. It's pretty much inevitable that this is going to be cheaper than coal- and likely cheap enough to make hydrogen for when wind is low. Cheap, guaranteed price, non-polluting.
Judging from nuclear's track record, it won't come close to wind. These turbines might not be the ones to put nuclear out of its misery- but wind certainly will play a large part (don't discount solar just quite yet).
Information: "I want to be anthropomorphized"
Is it really an advantage that it doesn't kill birds in these H5N1 times?
This link is the nicest derivation I have seen online of Betz's law regarding the maximum effiency (16/27 ~= 59%) of any non-compressible mass flow capture device. At least the article doesn't claim to exceed it (40%, I think). But as for high drag-devices getting a better effeciency than a variable-pitch propeller? That sounds pretty suspicious.
http://www.windpower.org/en/stat/betzpro.htm
On the other hand, if it can endure much higher winds than a prop installation, its OVERALL effeciency might be higher, because the energy in a mass flow is proportional to the cube of the wind-speed; so the 1% high wind speed tail of the distribution contributes a large portion of the total energy captured by the turbine. Of course, having a bit more REAL info would be helpful in determining if this is just slick FUD or something real. And when significant data is not mentioned, it does make one tend to think there is something to hide.
This design does not create "pull" on the leeward side. There is no such thing as a negative aerodynamic force.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
The energy you can take from the wind is proportional to the area of the device, and the cube of the wind speed. Three-bladed wind turbines are tall and big because wind is faster higher up, and so they can sweep a huge area. A three blade arrangement is aerodynamically optimal, getting closest to the Betz limit of about 59% (not 20-30% or whatever the web page said).
Also, bird death is about 1 per turbine per year for current technology. This is about 9 orders of magnitude less than bird death from buildings/vehicles/airplanes etc., and that's not considering the enviornmental consequences on bird life of NOT using renewable sources...
Dumpy little vertical axis machines may have limited uses in isolated installation, and for revolving advertising, but they are not practical for large scale generation. The rotor of a modern 5MW wind turbine is about the same size as an athletics track. Imagine how big this vertical axis machine would have to be to match the wind capture of this. If the alternative is to have many small devices, there would be a very large number indeed: this carries costs of electrical interconnection, massive maintenance overhead from trillions of puny alternators and gearboxes, all of which was probably ignored in arriving at the 2.5 cents per kWh.
The only way to make money with this turbine is to be the poor guy's patent attourney.
I would like to call a halt to posting links from Open Source Energy. The site is run by crackpots and kooks who espouse completely insane ideas that have absolutely no basis in reality. It takes about 5 minutes of browsing for any reasonable person to determine this. Promoting this site is bad for slashdot. I do not joke when I say that posting links to this site is no better than posting links to some "intelligent" design site about new theories of evolution.
I am skeptic; it still looks like a meatgrinder to me. O.k it does not look like the propeller desigh that chops the bird, but when that thing is spinning at speed I am sure it pets the bird in the back as gently as a bud hits you with 50mph windspeed from the back ....
.......
just a visual observation, and probably they threw some chickens into their grinder before they claimed that.
Besides being an asshole critic, I really appreciate the aspect of renewable energy paired with not being a traditional meatgrinder
fact: did you guys know that costa rica is only using wind and water power? In fact we produce as much from these sources that CR exports energy to neighbouring countries; clean energy. In fact, while still considered a developing country, electricity coverage is the best in central AM, technically you have electricity everywhere. For US/European readers it is probably normal, but when you drive around in Panama/Nicaragua you canappreciate grid coverage here.
OK, water energy creates some mess with the environment in some cases especially when you have wetlands, because dams can affect these in a bad way, but still better than burning coal or radiating, etc.
Modern turbine designs have taken these problems (and many others) into account and now kill very few birds - probably fewer than are killed by flying into electricity pylons. The main design changes are that they are much larger and slower rotating, so birds tend to judge the motion correctly and avoid them. Correct me if I'm wrong, but I think the Altamont Pass turbines are painted grey to reduce their visual impact against the sky, which also reduces their visibility to birds. Modern ones tend to be painted white, which makes them more visible.
On a recent visit to Denmark I was very impressed by the size and sheer number of turbines, turning gracefully, slowly and fairly unobtrusively. Occasionally there would be a small, faster-rotating one of an older design. These were noticeably more distracting and attention-grabbing - particularly in the peripheral vision (which after all is designed to look for rapid movement from predators). It's these older designs that have lead to most of the complaints from local residents, and understandably so.
Give me a modern turbine at the bottom of my garden any day - they are also virtually silent unlike their older cousins.
43 - For those who require slightly more than the answer to life, the universe and everything.
Hi,
I was at the UK national Bat conference this years and there were a couple of presentations on bat kills around wind turbines. It turns out that the strange noised attrach insects and therefore bats. Certain wind farms in the use, I forget which, are on migration paths for bats. There is a suggestion that they turn off the wind turbines come migration session.
Since bats are a key part of bug control, particularly in the US, you might want to think about protecting them,
Lonely
This is the third post I recall by Stirling D. Allan recently, the others being
The first in that list featured complete crackpot pseudoscience. The second seems to be of dubious scientific merit. A quick look at Mr. Allan's website shows they are involved with a number of other areas of pseudoscience (or to put it less kindly, scientific hoaxes) such as "magnet motors" and "zero point energy" (as an energy source). That together with the two other submissions he's made leads me to doubt the validity of the information in these "stories". The main problem, however, is that these are not balanced informative articles, but rather they seem to be little more than ads seeking venture capital. Furthermore, it looks like Slashdot is soon to become little more than a mouthpiece for opensourceenergy.org at this rate.
"You call it a new way of thinking; I call it regression to ignorance!" -- Operation Ivy
As silly as that sounds it is true...
e .htm not the real article). Essentially the windmills act like a wind dam and that changes the weather on nearby beaches. I think what the report said is that the beach received more sunlight than it usually would.
About six months past I read in a German paper that in the North where the windmill parks have changed the local climate (http://www.msr.uni-bremen.de/werner/rw/RWOffshor
"You can't make a race horse of a pig"
"No," said Samuel, "but you can make very fast pig"
it scales vertically. we built one with 6 55 gallon drums. 3 on the lower tier 3 on the upper tier cut in a way to have 6 blades per tier. all attached to the central shaft using a thrust bearing at the top and botton and then to a pulley that turns the rotor on a home built alternator at 3 times the rpm that the windmill is spinning at.
works great. put another next to it and now I get 2X the power generating capacity. add 3 I get 3 times the power generating capacity. that's the neat part 1 windmill does not slow down all the wind and scaling up works perfectly when you think of it in a multiples instead of one giant windmill.
a small village trying to be seld sustaining could create a farm of these and generate power. wind is not the only source you need, you have to couple it with solar. because the days it's not windy it's usually very sunny. and all of it needsto go into a storage system.
Typically simpler = better. because you can make more of them to compensate for the lack of efficiency that highly complex may or may not give you.
that's the problem with alternative energy, too many people make it complex as hell and scares the realy users away from it. Anyone can create a hang out your window solar heat collector that works fantastically well for about $19.00 in parts and a little time gluing, nailing and painting. But you only see the hyper expensive requires engineers to install systems advertised or talked about. same as solar electricity. you can buy your solar cells for pretty darn cheap, you do not have to pay $5000.00 per panel for new state of the art stuff.
Same as you do not need to be a aeronautical engineer and able to carve an airfoil propeller to make a good working windmill.
Do not look at laser with remaining good eye.
Wind farms do less damage to the environment than any other form of power generation other than solar, and kill fewer birds than the windowed office building that would be built to house the adiminstration for any form of power plant.
This is a serious issue and needs to be addressed! How did solar power get away with causing so little damage?? I propose that all solar arrays be built slightly concave, and reflect most of the light they don't absorb (we don't want to reduce efficiency), creating giant death rays. This way we can ignite birds that fly through the kill zone and correct this serious deficiency.
In an unrelated issue, I'd also like some serious effort to be put into breeding chickens that can fly.
Sure I'm paranoid, but am I paranoid enough?
Windaus Energy (Ontario, Canada) has developed prototypes of a vertical-axis wind turbine and are looking for places to install working demos.
From an announcement they sent out earlier this year:
Specifications are available on their website, including output, torque, power output. As other people have pointed out, there are some disadvantages to this style of turbine, but there are also some advantages. It looks far more suitable for local micro power than mega wind farms.
Put them on the corners of a skyscraper and the power is used only feet away from its generation.
Hmmm--this type of wind turbine could be perfect for the space on top of the planned Freedom Tower in New York Ciy that designers plan to install wind turbines inside that space. It would definitely be less threat to birds flying nearby and the noise level will be substantially lower, too.
Right- the AP picked up a story from the Casper Star-Tribune, which then got reprinted by the Seattle Post-Intelligencer, CBS News, Yahoo News, etc. That story was basically coverage of a press conference. I don't imagine there's a whole hell of a lot to cover on any given day in Cheyenne, so of course they'd be there. The fact remains that they don't have a production prototype, and haven't shown anything, so for now they're all talk.
Here are two companies who are offering commercial installations of VAWTs. Although they haven't sold many to date, at least we see that these are both past the R&D phase.
http://web.mckenziebay.com/
http://www.solwind.co.nz/vertical.htm
When I was in the Netherlands last year, I toured a large wind park north of Groningen. There, under the turbines, I saw a total of:
1 dead bird
1 dead sheep
From this, we can deduce that wind turbines are equally as deadly to sheep as they are to birds. The 800-1300 sheep killed annually must make the Altamont Pass a bloodbath of truely horrific proportions.
But seriously, folks...
The Altamont Pass is a disaster which was produced by irresponsible economic incentives of the time which put up low quality turbines willy-nilly throughout California. Add to that the fact that many of Altamont Pass's are placed on angle-iron framework towers. These make them ideal nesting grounds--well, if one ignores the 30 m food processor out front. Modern towers take great care in leaving no place for avian habitation.
This park's would otherwise be just a regional problem, but, thanks to more animal-focused environmental groups, and the tabloids who eat up their press releases, that wind park is biting us over here in Europe in the ass.
Altamont Pass is, however, the only wind park on earth with this level of environmental impact. Nothing comes close in these regards. A substantially larger off-shore wind park off the coast of Denmark (Knoetby, I think) actually showed that the birds weren't scared off, but instead kept a distance of about 150 m from the equipment.
I guess you didn't notice that the story was also run by CBS News and Yahoo News, among other mainstream organs.
They're all just regurgitating the same story/press release that originated at the Jackson Hole Star Tribune and was passed along to the AP. All this is is an advertisement for venture capital, the same as the last couple you submitted. Both you and Slashdot should be ashamed at running these adds. as if they were news.
"The back pressure creates a vortex that pulls it around, turning drag into lift,"
Every time people say such things in a marketing blurb, an aerodynamicist dies. Clap your hands! Clap your hands to save them!
Why yes, I AM a rocket scientist!
Your quote of the KE formula is incorrect (KE = 1/2*m*v^2), and your conclusion about cubes vs. squares is wrong, because a mass-flow capture device derives its energy from not just the SPEED but the AMOUNT of mass that goes by per second (i.e. the mass flow). So, if you double the velocity of the wind, the MASS part of the formula doubles as well as the velocity part; that is why the power (energy per unit time) is proportional to the cube, not just the square of the velocity in any mass-flow device.
Comaparing the dot com bubble of the late 90's to a simultaneous increasing need for energy and decrease in it's availability, and the solutions to that problem is like comparing the invasion of Iraq to WWII.
We play the game with the bravery of being out of range
This is the third time I get to post this link in roughly 2 weeks.
Sterling D. Allan's personal website. Check out some of the other websites he has founded and administers. Not to say that real scientists can't be religious or spiritual, but... come on... Given that the articles submitted here by Mr. Allan are more pseudo-science than anything, coupled with that list of websites, there's absolutely no reason this stuff should be on Slashdot, let alone the front page. Yeesh...
What's more dangerous, Slashdot; anti-science or pseudo-science?
People will pass up steak once a week, for crap every day.
It's strange that the sight of sails on boats moving laterally is ok and actually thought attractive by most people, but the sight of sails rotating disturbs some people.
to err is human, to forgive is divine, to forget is... umm...
There are several hard problems in wind turbine design. One is that, for large wind machines, wind speed may vary considerably across different parts of the blade area. This produces huge stresses in the blade system. Aircraft propellers and hubs don't have that problem, so technology borrowed from aircraft props didn't quite work. That's been solved, but it took years to get past it.
A basic problem, one which this new design doesn't solve, is overspeed protection. Wind turbines above toy size must be able to deal with high wind conditions safely. Some turn sideways; some turn upwards; some feather the props. Brakes aren't enough. There's no way to feather or turn this new design. Even small turbines need, and have, overspeed protection.
There are lots of wind machine designs that more or less work in a small size, but don't scale up to the point where they're worth building. There's a square law; double the blade length and get four times the energy out. So big turbines beat out little ones, once ths scaling problems are solved. Wind turbine size has been creeping up since the 1970s, from about 50KW to a few megawatts.
A 1.5 MW unit was built in the 1940s, but it suffered a bearing failure within a year, then a loss of blade accident which threw a blade 700 feet. Only in the past decade have reliable wind machines in that size range been produced in quantity. With 2800 of their 1.5MW units installed, General Electric can be said to have solved that scaling problem.
The big machines aren't simple. They have active yaw control, active pitch control, hydraulic brakes, AC to DC to AC variable frequency conversion, and lightning protection. But, at last, they work.
So these guys are going to beat that with a little tin model that looks like something used to spin a sign in a used car lot. Right.
To be quite fair to the grandparent, I've heard plenty of self-proclaimed environmentalists complain about aesthetics. Usually, though, they find some easier to argue position like "we have to think of the birds." Talking energy with them typically goes something like this:
Environut: Global warming is going to kill us all. We have to stop the evil oil companies bent of world destruction.
Engineer: Well then, let's invest some money in clean, reliable nuclear power plant design
Environut: Are you kidding. Those things are radioactive and they meltdown all the time. Plus Tom Brokaw says terrorists can blow them up with molotav cocktails and kill us all.
Engineer: I don't think you understand the issue fully, but ok, how about natural gas.
Environut: I heard through from my neighbor's, best friend's, third cousin who is an expert in environmental peace engineering at Evergreen Community College that natural gas tankers can explode with the energy of the atomic bomb dropped on Hiroshima.
Engineer: The stored gas has equivalent chemical energy, yes, but it's release is dependent on the oxygen that can be supplied. The absolute worst case scenario is a really big fire. Still, if you're not comfortable with that, how about hydro power in locations where it's available?
Environut: Disrupts salmon spawning.
Engineer: Wind power?
Environut: Kills birds
Engineer: Geothermal?
Environut: Haven't you seen Core? You'll stop the earth's core from spinning, cause earthquakes, and kill the yellowstone geysers. Engineer: Umm, how about tidal generators for coastal cities?
Environut: Absolutely not. They destroy the reefs to build them and devastate the shoreline ecostructure by reducing wave action
Engineer: How about investing in Fusion research?
Environut: Doesn't that involve atoms? I don't like atoms and I think they should be banned by international treaty because terrorists can build dirty bombs out of them.
Engineer: I suppose you have something against solar power too?
Environut: Oh no. I love solar power. It will save us from global warming, cure world hunger, end racism, and get Barbara Streisand elected president.
Engineer: Well, it does have its benefits, but it's only practical in a limited part of the world and it's currently nowhere near as cost-effective as other forms of energy production
Environut: I knew it! You're just another puppet for big oil. Why do you hate the baby seals? What did they ever do to you? Murderer!
Ok, that's exagerated a little bit, but I bet if I pulled snippets from enough old posts on Slashdot, I could come up with that conversation without too much trouble.
Actually, the absolute worst-case scenario is a BLEVE, which you Do Not Want. When all of the factors are right, heat from a really big fire boils the LNG in its tank, overwhelming the pressure-relief valve. The valve sends up a shrieking tower of flame as it fails to keep up with the rising pressure, and everything that I've read suggests that you shouldn't stop running while you can still hear it, because what happens next is ugly. The tank ruptures, sending shrapnel flying, and the pressurized gas explodes out, only to discover that it now has an opportunity to catch fire as it's already exploding.
This sort of "meta-explosion" doesn't happen every time some fire gets near a gas tank, of course: it's only the worst case.
That aside, it seems that about once every year or two a house somewhere in North America suffers from a natural gas leak in the basement and subsequent explosion that demolishes the house in question and badly damages the neighbouring dwellings. I've never seen an "enviro-nut" bring that up, though.
Mind the Gap
Your points are true only on a small scale, they fail on anything large.
All windmills slow the wind. If you add a second windmill, and the wind is blowing such that it would go from one to the next (in absence of any windmills/trees/buildings), the second windmill will see slower wind than the first, and thus generate less power.
All windmills create turbulence zones around them, mostly downwind. This too decreases the efficiency of the windmills downwind.
The only solutions to these problems is to space your windmills farther apart, or live with reduced efficiency.
As an aside, the above effects are why normal windmills have 3 blades, and not many - after every blade passes they need to wait for the slow wind to get out of the way to generate maximum power. (1 or 2 blade windmills would be better yet, but there are other technical details that make them less impractical in the real world) I suspect that you would get more power from your homebuilt generators if you got rid of a few of your blades - but of course you would need to experiment to see.
The last problem with scaling is you cannot just go up forever. There are substantial differences in windspeed and direction with altitude. Direction is mostly something airplanes worry about (and it doesn't matter to vertical axis turbines anyway). Speed is a different matter - wind near the ground is always slower than wind farther up. So if your turbine is tall enough, say 30 meters and near the ground, you lose energy because the wind higher up is acting as a fan to push the wind lower down. You can move the whole system up, but then you lose the advantage of the generators being near ground.
Simplicity is great, except that simple stuff may to be reliable. If you like tinkering with your windturbines as a hobby, this is not a problem. If you just want to use lights and such without worrying about the generation wind is not for you. The utilities can pay for complex solutions that are engineered to be reliable. They also have the ability to deal with unexpected problems. If one of your turbines breaks you are down to half power (assuming your solar input is negligible, you didn't specify so I don't know what it is), to the power company that is less than 1%.
When I saw the photo, I immediately thought of my local library's copy of a hippy-era how-to on building a vertical-axis wind generator out of 55-gallon drums, plywood and junkyard auto parts like axle bearings and alternators. It's called "Wind and Windspinners: A Nuts and Bolts Approach to Wind-Electric Systems" by Michael Hackleman.
Basically, you cut the drum in half longways, and then offset the halves from each other to form an "S" shape with the two halves overlapping slightly, so that wind enters the open side, follows its contour into the closed side and exits out the back. The book recommended stacking 3 such drums, offset 60 degrees from each other and with plywood circles between the drums to prevent spilled wind. If you want to get fancy, you build sprung gates into the backs of the drums so they can dump excess wind in a storm. There are some drawings and photos of the design here.
I think Hackleman's reason for championing the Savonius design had nothing to do with efficiency - instead, it was all about cost, simplicity and durability. Fits right into the microgrid idea - a small village in the third world could assemble a few of the cheap homemade versions of these and link them to a battery bank to get themselves some simple, reliable electricity for whatever they needed to power.
6. Audible Alarm (not shown)
-from a Cuisinart product owner's manual.