« A steam powered submarine: the Ictíneo | Main | The age of speed: how to reduce global fuel consumption by 75 percent »


Feed You can follow this conversation by subscribing to the comment feed for this post.



WOW WHAT AN ARTICLE, what a bunch of crap, LIES HALF TRUTHS AND IRRELEVANT INFO, first, micro wind turbines don't cost 26k for a residential solution, TRY 2-3k, you can get an Air X for $500 if you shop, it puts out 400w @ 26 mph wind speed but around 150-200 at 10-14 mph, 4 would cost you 2k and add another 1k for poles, mounts, wires and a charge controller. AS usual you bozo's go with your either or arguments on wind or solar, you WANT BOTH, their complementary, I have 40 solar panels(12K) and three air X micro wind turbines, I live in a suburban area, southern CA, together they supply 90% of my electric. I could give a $h1t how much energy it took to make them. All I know is I break even in 7 years, I've had them for 3 so I have 4 to go.

Kris De Decker


You don't care how much energy it took to make your windmills and solar panels ? Then you are completely missing the point, my friend.

People like you think they can justify an exorbitant high energy consumption with renewable energy, without realising that the energy needed to produce 40 solar panels and 3 windmills makes their households everything but green.

Someone who consumes 5 times less energy than you, and gets that power from fossil fuels, is damaging the environment much less than you are. You are just buying a clean conscience.



You're right, wind power sucks! We should all have fuckin diesel generators in our basements instead, yeah!

Kris De Decker


Very funny. The article does not state that wind power sucks. It says that urban windmills suck. As you can read in the article, the energy payback of a large windmill is less than one year: that's the way to go.

Kevin Coleman


From what I know about sustainable energy generation you have to take into account the cost of all the materials and their extraction required for the construction of your chosen device 'before' you can say whether its a good or bad method. A combination of solar and wind generation seems to be the way forward but it is still expensive in environmental terms. Need to force the energy generators to invest more in research and development of cleaner alternatives.
However from the previous comments it seems to me that some folks 'want their cake and eat it' and 'up' everyone else's.
Nowt like a caring, sharing community is there?
Interesting article though.



It is not cost effective or environmentally neutral as is, but it can be. It is absolute genius if natural materials were used. Large windmills capture only the wind energy from the the air directly surrounding it. Thousands of small mills "combing" the air would be much more efficient.



You're obviously in the pay of one of the major power companies. It's sad that people like you feel it's necessary to spread dis-information so that people will be less likely to try new technology and instead keep paying in their money to the mega corporations.

kris de decker


Read the article again. It states that urban windmills, because of poor wind conditions in cities, do not deliver the energy that was needed to produce them. The article also states that large windmills have an energy payback time of less than 1 year.

Conclusion: we should invest in large windmills, not urban windmills. I am not sure how you come to the conclusion that I am paid by Big Oil.

Large windmills do not need to be owned by mega corporations, if that is your concern. In Holland several collectives already offer the possibility to a group of private persons to invest in a large windmill.

The problem is the narrow-mindedness of many environmentalists. You read criticism on a green technology, so you automatically conclude that it must come from the oil industry. The world is more complicated than that.



I personally lived for 10 years in a bus with 2 50w BP solar panels and a 250W Aerogen wind generator. The panels were great an enabled us to live from March till October in the UK without any extra power. I spent many days watching the ammeter from the wind generator on windy days barely moving. Very sad. Very good article and I agree with you wholeheartedly. Also, have you seen these pocket fold out solar chargers for mobile phones etc....about as useful as a chocolate kettle.



I was just browsing the web researching the possibility of putting up my own windmill (small) on my on-acre lot in the desert (very windy, 3,000ft altitude.) Totally bummed. On the bright side, it looks like I couln't afford it anyhow. lol



There is a way to improve the environmental benefit of an urban wind turbine. You have the manufacturer leave the generator out of it.

Brent Eubanks


Environmental Building News, the most reputable and oldest of the green building industry magazines, has an article this month that comes to much the same conclusion:



Great link, thanks!

Dimitri Galani


The article was great: simple, well written and logical.
However, you do not appear to consider the fact that producing fuel oil -and transporting it the power stations- also uses significant amounts of energy: 1)drilling 2)extraction 3)Refining 3)transpotation and 4)distribution. There are also a significant losses on the power grid which 'transports'the energy to the households.
Taking all these factors into account may yet affect the equation.

It would be useful to consider whether wind-turbines on the roof of high-rise buildings would be efficient, as the air flow is certain to be more powerful up there.



Dimitri, you are right to state that it takes fossil fuels to produce fossil fuels (more and more, actually, see the concept of "Energy Return On Energy Investment" or EROEI).

However, this does not change the conclusion of the article at all, since I do not make a comparison between fossil fuels and small wind turbines. I am only talking about small wind turbines.

If you invest more energy than you get out of the process, a technology is worthless - whether it is a wind turbine, a nuclear plant or a coal plant.

Wind-turbines on the roof of high-rise buildings have been tested in the UK, with disappointing results. See this report:


cloud ponderer


The author has apparently missed at least one new innovation, available right now, at least in the U.S.) for do-it-yourself installation. I think the author needs a bit more faith in the POWER OF DESIGN. Urban wind is not impossible, we just need to stop trying to transpose one solution onto a different problem. ENGINEERS NEED TO LEARN TO REEXAMINE THE PROBLEM AND USE A FRESH—TOTALLY FRESH—PERSPECTIVE! That has been done beautifully here, utilizing the SPEED AT THE ENDS OF THE BLADES (rather than at the center, where speed is slower) and eliminating the weight, drag, complexity and cost of a gear box:


Kris De Decker


@ Cloud ponderer:

Either you are naive, or you sell these wind turbines. The claims of this manufacturer are wildly exaggerated, and simply impossible for a turbine of this size at a realistic wind speed. And if you don't believe me, take the word of this expert:


Peter Bird


Shame about the negative and abusive attitudes of some of the feedback. The simple point being made is that small wind gens are nowhere near as efficient as large scale units. The criteria for efficiency - in this article - being how much energy is use to produce the equipment compared with how much it produces. Anyone understands the simple principles of capitalism will relate.

What I failed to extract is the break even point. Does it take 10,000kw to produce a small wind gen ? if so and that gen is producing 1000kw per annum then after ten years the equipment is in the positive.

Along with this we need to consider how much power is being consumed through other means - including large windmills.? That may change the dynamics of the equation whereby small wind gens are in the positive after lets say seven years. If we then figure into the equation, the power consumed in creating the equipment for the 'other' power sources. then the dynamics shift even further whereby the small wind gens might well break even after just one or two years.

Personally I found this and the linked articles interesting and thought provoking. Perhaps only short of exploring the full breath of possibility and conclusion, but hey they are volunteers not mega buck businesses. I thank all those who contribute in a positive way. Criticism can be constructive or destructive - please let's stop belittling others - think about what you wrote and the way you write it.

Best regards, Pete



Urban wind turbines are often put forward by opponents of large scale wind turbines. It is good that you to expose this as a red herring.



While I do agree that many small turbine designs do not do well in an urban environment, you seem to have focused on one design from Home Energy and located that one design in Belgium or the Netherlands.

Since this article was written 2 years ago, may I make a suggestion that you revisit and learn a bit more about the varying power outputs of other designs? Honeywell has a new design that begins producing energy at a much lower wind speed than you keep quoting is necessary for the Energy Ball (which I agree is not worth the money or energy spent on creating it). That makes a difference in Urban areas.

It may be that turbines are not efficient enough in urban areas. I lived in Chicago for a number of years, and I believe that the even the occasional winds that roared through the city could be exploited for their energy. Many buildings had ropes and handrails so that you would not blow away.

Kris De Decker


Don: for an update of this article, including tests of almost 40 different types of small wind turbines, not only in the Netherlands but also in the UK, see here:




I actually just started working for a dealer of the Energy Ball so I'm doing some research. But I guess my comments could still be biased. :)

I think what is not mentioned by the author of this article is that one or more small wind turbines, combined with solar panels, may actually turn an incomplete renewable energy solutions into a complete solution.

The benefits of even a small amount of power generation during the night, when we typcally use less power anyways, or on a cloudy day, could actually turn an inviable solution into a viable solution for many many people.

You may think this is false, if it is like you say, that it takes more energy to produce than it will ever return. Because you could just get the same amount of power from the grid.

HOWEVER, it really depends on your exact location and the cost of hooking up a new home to the grid just for example. Just one minute outside the city limits and you're probably looking at a heafty charge to be connected and lot of energy to get you hooked up unless the tax payer pays for it, I honestly don't know.

But what about camps 5 or 10 minutes away, and smaller towns that can't afford the installation and maintenance of power lines. And wouldn't it be nice to build virtually anywhere you want instead of sticking houses six feet apart.

But I think the biggest thing that most people might fail to consider is that once you have the product, you can probably maintain it and refurbish it for hundreds of years! Sure some things may need to be replaced but it's not going to completely disintegrate in 20 years!!! LOL

If twenty years from now all you have to do is replace a coil and/or some magnets, maybe even a blade or two, but then have it run for another 20 years, and then your kids do the same and their kids!

And then you have to also consider that the energy to produce it may have actually been or will eventually be supplied by thousands of solar solutions that were made viable by what, you guessed it, wind turbines!!!!!!!! And who knows, if the construction process is actually 70% manual labour or if it's eventually lowered by investing in the company that creates it then how much cole did it or will actually burn?

Obviously, if your home is already connected to the grid, and you're in a an area with very little wind, I won't say it's can't actually be a bad solution, because I honestly don't know and I'm not a liar. But that doesn't make it a bad product that has completely no use or benefits.

ALSO, in many cases, raising the Energy Ball's height might be all you need to improve it's roi. And last I checked, once you invest in a pole, it's going to stand for an extremely long time, unless you have a little too much to drink and ram your car into it. LOL

You also have to remember that the Energy Ball also solves the issue of noise issue. And it does come in a large version now. This article seems rather old and doesn't seem to mention the V200 model.

Obviously I think the real benefit of small wind turbines is if you want to get off the grid completely. There's no bill to worry about, no paper invoices in your mailbox, no blackouts to worry about which could easily increase in the near future (not scare tatic just my opinion).

Basically it's an investment.

Palomar bob


All wind turbines should be required to show kwh/day; kwh/mo; kwh/yr only
Grid requirments ( cb amps ) ( volts ) etc
Never any estements of anykind anywere
Maps showing kwh/?? For that make/model
On Map of zeeland you would find ( 73kwh/yr energy ball v100 ) ( 330kwh/yr airdolphin ) ( 578kwh/yr passaat)
( 2,687kwh/yr montana ) etc
On map of northfield, minnesota ( 4,000,000kwh/yr micon 82 )




We are 6-7 years after this article was send out. At the time we can consider it was still very new in people's mind.

now things have changed. Technology in this particular sector has made huge improvement during the last decade. A lot of small companies have shown up with nice light green projects.

so question is, wouldn't it be nice after to have a new article on this subject based on these new technologies that poped up ?


kris de decker


@ Coralocean

There is no need for a new article on this subject. The design of the windturbine hardly matters.

Doubling the rotor radius of a wind turbine increases wind power 4 times. Doubling the wind speed increases wind power 8 times.

Tiny wind turbines will never achieve good results because of their size and because of the low and turbulent winds in urban environments.



Well design of energy ball is strange and I agree that wind power plants in that scale are waste of money, but maybe something bit bigger on high buildings could give reasonable power output.

For some time I was thinking about clothing power generating facilities into "traditional" clothes, just put gearbox and generator into windmill. I think it will make smaller damage of landscape than modern wind power plants, especially on land.



There are plenty of places in urban environments that have MORE wind energy than a wind generator on a modest pole out in the country. Anyone who has tried standing near the appropriate corner of the John Hancock building on a breezy day knows that this is true. Sometimes it seems like it's windier for half a block or so around that building. The wind near the corners of skyscrapers is accelerated significantly. If you put modest wind turbines on the roofs and corners of skyscrapers, they will see a lot more wind than anything on most houses. The Hancock in Boston sees so much wind that it had to have a carefully damped, extremely heavy weight sliding around on an upper floor to keep it from oscillating too much. This article is like saying that solar panels are no good because they don't work well if placed in the shadow of a tree!

It may be that, say, large offshore wind turbines are more efficient, but that doesn't mean that small ones installed in appropriate places can't generate much more energy than it took to put them there. Especially if you pick one somewhat larger that works well.



There are some nice DIY windmills made from discarded ceiling fans and rare earth magnets. The embodied energy and cash i nvestment is small, the out put modest,but I think they would useful wired to a water heater element to take over the job of maintaining tank temperature.




If you're going to go to the trouble of setting up a wind generator, take a few hours and carve a decent set of turbine blades. For two blades, I'm sure two or three hours with a 2X4, a drawknife, a plane and some sandpaper would result in a far more efficient blade that was also more robust. The ceiling fans I've seen don't have any twist in the blades, meaning that large parts of the blade will be either stalled or causing net losses. Furthermore, I haven't seen many that have a cross section anything like that of an airfoil. Do a web search on "dannysoar prop carving". I'm suggesting something similar but on a larger scale. One thing to remember, though, is that a turbine will have the flat side on the front of the blade, not the back. Also, for, say, a 6 foot turbine made from a 2X4, balancing is going to be a lot more important.

Water heaters, if you take showers often, are going to take quite a bit of energy. So you'll need a relatively large turbine. I'm talking over 1,000 kWh per year, if your winds are steady. A heat pump style water heater might reduce the requirement. And if you also run a dehumidifier, the head pump water heater will reduce the power your dehumidifier consumes. Using electricity from a wind generator to heat water with resistive elements wastes a lot of energy.

First, you have to convert that mechanical energy to electricity. Some of that energy will be released as heat, but not inside the water heater. I'd say at least a quarter if you've done all your engineering perfectly. If not, considerably more heat. (I'm not counting the heat from the aerodynamic inneficiencies of the turbine itself, since some of that is inherent in any wind turbine. OTOH, if you're using a ceiling fan.....). If you put your turbine directly over the tank, you could drive a plunger or propeller inside the heater, which would heat the water. Or use a driveshaft to run your generator INSIDE the heater, so that you harvest the waste heat. Assuming you can keep the water out of the generator, anyway. That's all a bit tricky, of course.

For hot water, direct solar heating of the water will be better. Ideally, you could use the heat from the back of photovoltaic panels, thus also cooling the panels. But even if you just use aluminum or copper sheets with tubes with water running through them, that will be more effective, I think. The low grade heat generated this way would be hard to generate electricity with, but just right for a water heater. Save the electricity for lights, electronics, etc. Hmmm...I'm imagining a combination water heater/high powered computer. ;-)

BTW, I'm the same LR that wrote comment number 27. I'd forgotten it and was all set to write the same things again.

Caveat: Maybe if you can skip all the fancy electronics and just run whatever current you get through the water heater coils, you can skip a lot of work building the equipment. You won't even need a rectifier. Also, model airplane brushless motors are cheap these days. So if you can spin them at efficient speeds, it might be a good way to go. I wonder if there's a way to use the electronics speed controls for those motors to regulate the resistance the turbine is pushing against to maintain the most efficient speeds. I've that a good set of turbine blades would be most efficient when the tips are going about 10 times the wind speed. The speed control might be able to maintain that ratio without having to have variable pitch or something.

I'd better sign off. I'm supposed to be doing something else!



I often find myself thinking about articles on this website long after I have read them. I don't understand some of the parameters that seem to be assumed when discussing urban windmills. Why do they need to be small? Having looked at the article on direct heat generation through hydraulic braking, I'm envisioning large windmills on the top of skyscrapers in coastal cities like Chicago for hot water heating in the summer and a supplement to the boiler in the winter. I imagine the drag created by a large windmill could be very substantial, and I'm not sure how that could be accommodated by existing structures, but it seems like these large residential installations take a lot of energy to heat and a mechanical heating solution could be efficient.

kris de decker


@ Tommy

Large windmills are not in residential areas because there's always a chance of a blade failure: https://www.youtube.com/watch?v=CqEccgR0q-o

The comments to this entry are closed.