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Clip-on wind turbine aims to supplement solar panels


August 1, 2013

The primary niche is to clip the generator to the top of existing solar panels in large arrays

The primary niche is to clip the generator to the top of existing solar panels in large arrays

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Crowdfunding has come to the small wind generation field with an Indiegogo campaign intended for an interesting target niche: a small wind generator designed to be clipped onto solar panels. According to its pitch, Cleantec Wind has not only created a prototype, but calculated possible energy returns, targeted a price point and lined up suppliers for initial deliveries and has turned to Indeigogo to get his small startup off the launch pad.

Cleantec's idea is to add lightweight narrow-profile wind generators to the top edge of solar panels. This would put the wind generators a few feet above the ground and in the very turbulent air that will exist in a hot solar array with wind blowing across it. This is an interesting proposal. The solar panels already generate electricity and are already tied into the grid for that purpose. (However, solar farms are engineered for the weight of the panels, the shadows that the panels cast and the output of the solar farms, so the prospect of strapping on a wind generator poses some challenges.)

Another interesting element is the Indiegogo campaign itself. Cleantec has created a range of low-end to high-end rewards for contributions, including working devices. The company has a simple prototype and renderings which do not reflect what they consider the final product.

The wind generator itself is a fairly standard multi-blade Savonious drag generator, which means its output will likely be lower than Darrieus or tri-blade horizontal-axis wind turbines. That's acceptable if the niche fits the generator and price point is appropriate for the amount of energy produced, but we wonder if a Darrieus generator would be a better fit. Both Savonius and Darrieus wind generators have axes parallel to the blades and are typically referred to as vertical-axis wind turbines. The difference is that a Savonius generator uses drag only to capture energy from the wind and has greater upwind drag on the opposite side, while Darrieus blades typically have an aerodynamic component for added speed, lower upwind drag and hence greater generative capacity. Textbooks since the '70s have included standard graphs of power curves for these types of devices.

The generator is claimed to produce 2000 W output, greater than a typical solar panel it might be attached to. At present, any test data or independent testing of the prototype that might have been used to validate the 2000 W is not publicly available from the company's website or the Indiegogo campaign site, though Cleantec's intent is to make it more efficient with such things as curved blades to catch wind from more angles, magnets to reduce resistance to lower start speed and high-efficiency bearings. Such optimizations are familiar on small wind generators like this, and have not historically proven to be economically justifiable when full lifecycle cost of electricity calculations are done. There are many of these types of devices that possibly could be retrofitted for the niche at lower cost via an OEM model rather than creating a new one from scratch, and this might be a direction Ring could choose to go if the engineering difficulties start to mount.

Though the proposed device may not be perfect, Cleantec's suggested an interesting niche for small-scale distributed wind, potentially increasing the output of solar farms in the day and yielding generation at night.

Source: Indiegogo

About the Author
Mike Barnard Mike Barnard is Senior Fellow - Wind, with the Energy and Policy Institute. He has been a deeply interested observer of energy systems for three decades. His work as a business and technical architect on large initiatives in a variety of domains gives him the systems thinking perspective and stakeholder analysis skills to engage effectively with an area as complex as the grid. He’s regularly asked to peer-review academic and non-academic publications related to wind energy by journals, organizations and individuals. Through the Energy & Policy Institute, his blog barnardonwind.com and other venues, he focuses on bringing data-centric reality to bear in policy, siting and social license discussions related to wind around the world. All articles by Mike Barnard

Just a little more dangerous than the guys at Mythbusters. Looks like a little back of the envelope calculation, some quick CAD models, Google search, some what-if thoughts and presto - 'ready to rock' in their own words. No prototype, no testing, no thought of how the induced torque/momentum on the panels, etc. will be problematic. Cost points are speculated with no backing based on a bill-of-material for yet to be determined components. But hey, there are enough folks out there to buy into the big vision of it's easy, cheap and good for the Earth, that they may find some backing.


2000 watt hours, maybe. Inefficient design (tri-blades are best), poor placement (low to ground), and not capable of turning into the wind.

Another crowdsourcing boondoggle.

Guy Macher

I think it would be good for when there is little or no sun light but the wind is still present. As mentioned, it would be also good at night time.


Well, I would dispute the 2000Watt output number.

Looking at the photo and using standard panel width of 3.5 feet, I estimate the blade portion of the unit covers a swept area of 12' X 1' or 1.11 M^2

Using the standard formula for Power available in the wind: 1/2 Air density X Swept area X Wind velocity^2 (all figures in metric) I get: 1.11 m^2 (12' X 1 = 12 sq feet swept area) 8.94 m/s (20MPH) Air density = 1.23 KG/M^3 power = 1/2 X 1.23 X 1.11 X 8.94^2 = 54 Watts

So theoretical maximum is 54 W. Considering this is a drag machine which operates at low efficiency and even the best machines operate at well below 100%... 2000 Watts is pure baloney.


It is hard to imagine this being a better approach than even a small tower with a standard type turbine attached. Savonious rotors are bad for power generation because of their low top speed and mounting them horizontally gets rid of their big advantage that they can accept wind from all directions. This is just a bad idea all around.

Michael Crumpton

These things are not so hard to invent as long as no regard for real feasibility is given. Even large scale VAWT setups have infinite payback time: they will never pay the initial investment back.

With these things scale is a factor - as in small is less efficient. There is simply no way that these things will ever be financially sensible. And neither ecologically - the power created will simply be minimal.

The idea that a pair could light up street lamps is out of this world. Even if you are not aerodynamics specialist do a little research - you can get in the right ballpark quite easily.

Kent Risine

I wish I would have thought of that, that's a great idea, on a existing platform. that and it would keep the birds off the cells.

Jay Finke

Gotta love Ring's idea of mounting them "on existing infrastructure such as pipelines" (see caption on second image). Oh, the irony.

But seriously, the streetlamp application would work with LEDs.

Fritz Menzel

More horse poop from CAD savvy young minds that haven't a clue of the physics behind their fiction.


The idea has potential in places where the wind often comes from a similar direction to the the sun (north here). The biggest problem I had with my solar powered house was when it was cloudy for a couple of weeks, and something like this would have helped. As mentioned, the wiring is already there which is a good thing for losses


I like it. The wind often blows when the sun don't shine. Could be used to supplement a rooftop home PV.

I suggest instead of clipping it to the solar panel, make it longer and able to be clipped to the roof ridge of the home, facing the prevailing winds.

T N Args

Can see many problems here - for a start, solar panels are linked to sunshine direction, would more often than not be at odds with prevailing wind direction, limiting power generation straight away. There is also the disturbance of wind flow on surrounding panels, disrupting cooling, as panels have a reasonably small 'window' of heat tolerence for best eficiency.

The Skud

This has no basis in reality, just because you can have an idea and use sketchup does not mean you havea viable product.

I have designed solar parks, they are based millimeter perfect to get the modules as close as possible without causing shadow on the next row, this device would cause shadow across the bottom of the rows causing a HUGE drop in generation, this would certainly not be made up by the tiny generation of the turbine.

The wind uplift is likely to either pull it off the module, or tear the thing apart.

The reason people build solar parks and not wind farms is often due to the maintenance concerns associated with turbines, i get a feeling these would need repaired every week.

Devices like this should not be getting crowd funding unless they can at least come up with proof of concept, if not a working prototype.

Chris Jackson

Phony , the wind also moves west east or east west , the sun is in the south . The math on this idea doesn't jive .

Gianfranco Fronzi

geronimo & Co are right on the nail, by the time you've made this large enough to be efficient enough to be useful enough it'll go flying from the roof in a strong breeze taking the solar panel with it! Back to Physics 'n Maths 101 lads, but with a little Common Sense this time.


Yeah, this definitely doesn't pass muster on the recent Gizmag articles about how to spot phony wind turbine claims or the dangers of crowd funding.

If someone were crowd-funding turbines using recycled bike parts and re-purposed tool-motors-turned-generator (or re-purposed hard drive magnets and some good way of getting inexpensive tightly packed wound conductor), I would jump on it in an instant - I think the real innovation in wind technology is in reducing production/repair cost, not in building a better turbine. After all, if I can afford to cover my roof in, say, 20 turbines that average 5Whr output for less than the cost of one turbine that produces an average of 100Whr output, then I've done well AND I've reduced my risk of loosing electrical output due to an equipment malfunction (I'll be reduced to 95Whr while I repair or replace the generator instead of reduced to zero). That's obviously not a plan that will attract big power companies, but for us small-time peeps, it would be perfect for taking advantage of areas that get air flow but a fair bit of shade.

I could also imagine that, while solar installations don't have room for windmills, big windmills DO have room for solar installations if the panels are cheap enough.

Charles Bosse

"Interesting" all right. The hard result of this is that it turns off good people on clean energy when they get financially taken by devices that cannot provide what they promise. Like the tiny windmills to mount on the peak of your roof that claim to power everything in your house. These scams just make people hostile to wind energy in general.

S. Willey

Charles, I like the way you think. If the solar panels keep getting lighter and if the flexible ones actually will hold up, it should be possible to mount them in many places where we have not done so before.

Greg Ewing
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