Kite Turbines

I must admit that I see no future in a kite based generating system. Yes the energy is up there and it is happily exploited from time to time by miles high convection cells called thunderstorms. The idea of a million dollar chunk of hardware been fed into that is not attractive.

So a lot of that wind energy needs to be consumed flying the kite into high altitudes that are possibly quiescent. This while supporting the dead weight of the tether. What is more, there is no way to haul it down and land it conveniently at the local airfield. What are these guys thinking?

The only fix that I can see to the design concept is to add another tether on this sucker and attach super balloons that somehow find a quiet spot above this contraption.

Anyway they found some money and some folks do have the fever and some of the design ideas even look interesting. This song will not end until a few of these devices crash spectacularly.

Somehow the idea of a large power generator flying aloft over my head is not reassuring no matter how lightly built. That begs a very big question. Where do you put these suckers if you actually have a system that you trust to perform? There is no way to secure point of impact if something goes wrong.

I am trying to be generous here but I admit to difficulties. I also am not certain that problems might abate as the device is scaled up as has happened in most other energy technologies. After all the wind turbine business took off once the larger sizes were available and that would also be true for tidal power.

Anyway, let us wish them luck and hope that they can surprise.

September 14, 2009
Kitegen Update

http://nextbigfuture.com/2009/09/kitegen-update.html

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgezcqhSy1Rq3KBQaZEjHFON60Y0Xtw4yo6U5i3aRomca69al5tC63efe1Yk4ejsX4NN17gk2jIwDShNVgc-ZktNE_bEl1uQ_FboDU-F0cV1mpaB0SjhrlFJAAKF8TkdqnmBz_RJNu6v3o/s1600-h/kitegen1.jpg

Popular Science's most recent magazine (on newstands Sept ,2009) has a brief two paragraphs which indicate that Kitegen is building a 3 megawatt system with 1500 square foot kite sail. This is scheduled to be completed in 2011. This is 75 times larger power than a 40 kilowatt demo system that was produced.

•max power: 40 kW
•lines length: 1000 m
•kite area: up to 20 m^2
The new system will have
•max power: 3000 kW
•longer lines
•kite area: up to 150 m^2

About 5 months ago, this site noted that kitegen had gotten funding for larger project work and the developers indicated in the comments and email that the funds had not been dispersed at that time.
Here is a 39 page presentation from May 2009 by Mario Milanese on Kitegen.

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEheNZqBmm3n9888pm7MUX63J_lL3F9MoIiiicz0rpx5B0dsFcoUqqmAj0lZt-PzdblLe0dLY-tHmlGQiap44sijDvj0LUi0-_uOEqjkzgSUhtCQTHWfv_Iexvwqe00fVh0ynCXVuJCG9Ws/s1600-h/kitegen2.jpg

OTHER HIGH ALTITUDE WIND PROJECTS* Sky WindPower, S. Diego

* MagennPower, Ottawa
* Laddermill, Delft University

The winds in high-altitude jet streams hold roughly 100 times more energy than all the electricity being consumed on Earth, according to a study by Stanford environmental and climate scientists Cristina Archer and Ken Caldeira.

High-altitude winds hold a huge energy potential waiting to be harnessed. “If you tapped into 1 percent of the power in high-altitude winds, that would be enough to continuously power all civilization,” Caldeira said. In comparison, similar solar cells would cover roughly 100 times more area than a high-altitude wind turbine, he said.

Archer and Caldeira found the highest wind densities over Japan, eastern China, the eastern coast of the United States, southern Australia and northeastern Africa. Included in the analysis were assessments of wind energy above the world’s five largest cities: Tokyo, New York, São Paulo, Seoul and Mexico City. “New York … has the highest average high-altitude wind power density of any U.S. city,” Archer said.
In order to capture the energy in these jet streams, manufacturers are developing a variety of kite turbines that convert kinetic energy in wind to electricity. Manufacturer Sky WindPower designed a model consisting of a single tethered kite of four connected turbines, each with spinning rotors. The kite transfers the electricity back to a hub on the ground through its tether.
Another model, being developed by Kite Gen, looks like a rotating carousel, based on the ground, with several kites tethered to it. Each kite’s flight pattern is controlled from the ground to capture the most wind, and as the kites circle in the air, they catch the wind and tug on their tethers. The tension triggers a pulley system that converts the energy of motion to electricity.
Though sky-high currents offer huge potential, kite fliers face the challenge of a fluctuating wind. “While the winds at high altitude are much more consistent than the winds at the surface, they’re still not consistent enough,” Caldeira said. For example, if you flew a kite turbine in your backyard to power a house, at some times the wind would blow and at other times, it wouldn’t, he said. As a result, there would be gaps in the flow of electricity.

Magenn Wind Power Generation

I was introduced this morning to this ongoing project at

http://www.magenn.com

Although anyone can sketch out the likely difficulties, the promise is certainly there for a major new source of constant energy supply. I have copied their FAQ and have interspersed a couple of comments there.

This is clearly a serious effort by folks with real knowledge and skills and it is good to see this happening.

My general comment is that this will quickly come down in cost per kw. The present initial pricing is at $3.00 to $5.00 for a small unit.

More critically, it opens the door to major off grid industrial energy production. A large factory normally has to be sited on grid and grid losses are built in. Here we have our power source within a thousand yards of its application which means a huge increase in overall efficiency. Any small town can both contemplate producing their own local power sharply dropping the cost, but also can attract manufacturing to their locale. The manufacturer gains a secure local work force, and a secure local power source.

The promoters see the usual very remote opportunities. I see every small town as a viable customer. Yes they are on the grid, but having a convenient primary source of power at home and even the capacity to wheel any surplus onto the grid is very attractive, particularly if we want to adopt municipal electric cars as a major energy conservation strategy.

I also question the ability to handle weather related problems, but this has been the primary problem of balloons and blimps from day one and they have generally been sorted out. Hauling the device down is actually the final recourse and all weather systems provide ample warning. Icing may be another matter.

This innovation makes economic distributed municipal scaled energy generation a viable option. And for every kw that you have released back to up stream users, you have also likely released another kw used to overcome line losses. I look forward to seeing a 1000 kw unit built which should be quite suitable for a small town of a 1000 or so. That size should be producible at a much lower cost also.

FAQ

1. When is Magenn's "Floating Wind Generator" or Air Rotor shipping?

Magenn Power is currently in the prototype phase of our Magenn Air Rotor System (MARS). Magenn Power plans to ship our first official product, a 10 to 25kW version in the later part of 2009/10. Magenn will not be shipping a 4 kW sized unit as previously planned.

2. What is the Magenn breakthrough?

Magenn's breakthrough is based upon three decades of experience designing very large inflatable structures. The Magenn Air Rotor System is a closed inflatable structural design with inherent integrity, stability, and low cost. Furthermore, MARS is a buoyant system that only requires a low cost tensioning cable to secure it and transfer energy to the ground. When considering aerodynamics (Magnus effect) and other properties, the result is a device that is elegant and is projected to be more cost efficient when compared to competing wind energy systems.

3. What is the projected life span of a Magenn Air Rotor?

In some cases, current aerostats (blimps and balloons) made of the same materials have lasted over 20 years. Magenn assumes a depreciable life span of at least 15 years before major refits are required.

4. How does MARS stay aloft?

MARS is filled with helium gas, which is inert and non-flammable. The lifting gas creates a lift force that is in excess of the total weight of the system. The helium provides at least twice the positive lift versus the overall weight of the MARS unit. Additional lift is also created when the rotor is spinning in a wind. The aerodynamic effect that produces additional lift is called the Magnus Effect.

5. What is the Magnus Effect?

This is the same effect, discovered in the mid 1800's, that creates lift when a spherical or cylindrical object is spun while moving in a fluid. A dimpled golf ball, hit properly, has a back spin that causes it to lift in flight. A baseball curve ball pitch uses the Magnus effect. Basically, a back spin causes a low pressure region to form above the object and high pressure to form below, resulting in lift. A large object like the Magenn Air Rotor creates substantial lift, so much so that the device should actually work in a wind, without using a lifting gas.

6. Why are two types of lift useful?

The combined lifting effect from buoyant (helium) lift and aerodynamic (Magnus) lift help stabilize the Air Rotor against "leaning" in the wind. In tests, an Air Rotor went straight up and held a near vertical position in various wind speeds, since the Magnus effect increases as the wind speed increases. Our research indicates that maximum lean will never be more than 45 degrees from the vertical. One can buy inexpensive wind rotor kites that demonstrate the Magnus effect. They are called Hawaiian kites and are interesting in that they go straight up in a wind; much straighter than a foil design or other kite designs.

7. Is the total lift sufficient to lift generators and other equipment?

The bigger the MARS unit, the easier it is to build heavier stronger structures, envelopes, and generators. As an example, the largest MARS units planned (100' x 300') will have tens of tons of buoyant (helium) lift. This is well in excess of the overall Air Rotor system weight.

What I find particularly attractive about this concept is that it will have declining cost curve against increasing scale and improving aerodynamics. Just as large ships are also better, so should this device.

I have always been a fan of airships, but their proper development needed modern materials and increasing scale to justify the economics. I always liked the idea of hauling fresh fruit and vegetables from California to New York at eighty miles an hour without any vibration and a modest fuel expenditure. Oh well.

8. What's the difference between a Magenn Cylindrical Rotor and propeller wind mills?
Other things being equal, Magenn Air Rotors are 50% as efficient as the best propeller rotors, in terms of their wind "intercepted area". For a standard propeller system, this is the circular "swept area" of the propeller, and for a Magenn cylinder, its "wind facing area". Thus Magenn must have an intercepted area twice as large to produce equivalent output. However, there are other factors that will boost Magenn efficiency such as being able to deploy above ground mechanical turbulence. Magenn cylinders are basically strong, closed structures and therefore can be built in large sizes at low cost -- substantially reduced capital cost in comparison to the propeller units.

9. How is the swept area of the Magenn Air Rotor compared with that of the traditional turbine?

Wind Turbine swept area efficiency is crucially important to a flat plate wind turbine, but in our case it is not, since we can increase the size of our rotor at little cost and get equivalent or better "economic efficiency" per unit of swept area. Magenn uses 40% to 50% of our total rotor frontal area to calculate swept area efficiency. What is important is the overall cost and the rated output.

10. Why use Helium?

Helium is a light inert gas and the second most abundant element in the universe. Helium was discovered in 1868 by J. Norman Lockyear. Helium provides extra lift and will keep MARS at altitude in very low winds or calm air. It is also plentiful, inexpensive and environmentally safe. Helium's inert quality over other lifting gases makes it very acceptable in North America. In other parts of the world other lifting gases will probably suffice due to availability and low cost.

11. What about using Hydrogen?

This flammable gas is lighter than air and the most abundant element in the universe. Henry Cavendish discovered that hydrogen was an element in 1766. In Third World applications, hydrogen is an attractive and inexpensive candidate for the lifting gas. The use of hydrogen will be the subject of future MARS testing.

In fairness, hydrogen has always been problematic. It does enter into chemical reactions and it just loves to leak away. Since lift is needed only to get to altitude, were aerodynamic lift can take over, it makes more sense to avoid hydrogen.

12. What type of inflatable material (envelopes) will be used?

MARS will be constructed with composite fabrics used in airships today. The fabric will be either woven Dacron or Vectran with an inner laminated coating of Mylar to reduce porosity and an exterior coating of Tedlar which will provide ultra-violet protection, scuff resistance and color. Dacron is used for boat sails, Mylar in silver toy helium balloons, and Tedlar is the plastic coating found in all-weather house siding.

13. What about weather, lightning and service?

The US military uses inflated, helium-filled aerostats that are 400-ft in length and are tethered at up to 15,000-ft in altitude. These aerostats are illuminated, including the tethers, and indicated on all general aviation charts and Notams (Notification to Air Men). The aerostats carry many tons of radar equipment and are powered through the tether which is connected to ground winches which raise and lower the aerostat for servicing. Lightning is not a problem since the aerostats have lightning arrestor equipment. Also, helium is non-flammable. MARS units will be deployed at much lower altitudes, thus simplifying all of this.

14. At what altitudes will Magenn Air Rotors be deployed?

MARS will be deployed up to 1,000-ft altitude at this time. The benefits of higher altitudes are being investigated. Future MARS units may be deployed at altitudes far beyond 1,000-ft.

15. What about positioning and wind direction?

Due to the inherent elegance of the design, the Magenn Air Rotors will always weather-vane properly. Regardless of wind direction, the deflection disk will ensure MARS units will automatically rotate toward the wind, with the Magnus aerodynamic effect creating additional lift.

16. How does Magenn altitude compare with the big fixed tower Wind Generators?

Magenn Air Rotors will be deployed at altitudes up to 1000-ft. The maximum height of the GE rotors are approximately 400-ft, which is still subject to ground turbulence in most locations. The big fixed tower windmills still need to be located in specific high wind locations often near the coast.

17. Can Magenn Air Rotors be deployed anywhere?

Yes almost anywhere, deployment flexibility is inherent in the system. Its deployment flexibility, its rapid deployment capability, and its limited maintenance requirements create markets that are not available to other wind or solar energy product manufactures. MARS units will be deployed for disaster relief, to third world communities with limited or no infrastructure, for various military applications, to remote locations, and in harsh climates.

18. What field testing have you done on the MARS to establish its reliability?

We have tested all individual components. Three important, and well documented, test areas from our airship research and development have included validation of the envelope structure, aerodynamics (Magnus effect) and more recently the best blade to drum configuration. MARS units will undergo extensive field testing before they are put into full production.

19. What is the maximum wind speed that the MARS can tolerate and still remain airborne?

MARS can operate at speeds greater than 28 meters per second. The MARS uses torque (load) as opposed to velocity (speed) to transfer energy from the wind hence it has very good low speed characteristics and broad speed latitude. The maximum wind speed is dictated by structural integrity, and not tip rotation speed, therefore, the larger the MARS the higher the wind speed capability.

20. Are there any features or controls that keep the MARS from over-speeding?

Yes, over speed controls are built into the design of MARS. On the larger MARS units, excessive speed is controlled by moderating tether height.

21. Is the deflate system used in case of excessive wind speed?

A deflate system (common on all blimps) is an emergency system that would only be used if for some reason the rotor broke free or other extreme emergency.

22. Is there any transmission of data from the MARS to the ground that monitor the performance or signal that there are malfunctions that need attention?

Yes. Pressure is constantly monitored and controlled. Rotation speed, wind speed, and generator functions are also monitored.

23. What type of generators will be used?

Depending on size, either DC or AC generators will be used, with rectification as necessary.

24. Do the generators use a drive that increases their rotational speed relative to that of the rotor?

Yes, the generators support the axle ends, but are off axis and slightly below the axle. They act as tether anchor points. In all cases the rotation speed is stepped up by a simple gear arrangement.

25. Is there any equipment on the ground, other than a transformer, needed to regulate or in some way transform the electricity transmitted to the ground? If so what sort of equipment is required?

Magenn anticipates that MARS units smaller than or equal to 10 to 25kW nameplate capacity will be used mostly in off-grid applications, such as for backup power for farms, emergency response or Third-World villages. The off-grid configuration (at an additional charge) will include a charge controller, storage batteries, and a DC-AC inverter to supply AC output at mains voltages. This equipment will be on the ground. Mains voltage is 120 Vac 60 Hz in North America, and 240 VAC 50 Hz in Western Europe and many other parts of the world.

When in production, large on-grid MARS units used for commercial power generation will be configured differently. The plan is to use variable-frequency (doubly fed) AC generators, so that the generator can remain synchronous with the grid and get the most out of the energy in the wind without motoring off the grid or causing excess reactive loading. The generator controller, protection and grid interconnect equipment (including voltage-matching transformer), and a winch to regulate the elevation of the MARS above the terrain will all reside on the ground.

In summary, Magenn's aim is to send airborne as little equipment as possible (i.e. we aim to keep things on the ground if possible). In all instances, Magenn will provide all necessary equipment to interface our unique generation system to conventional loads.

26. What voltage is generated on the MARS?

Customer specified DC or AC - 110 to 240 volt, 50 to 60 Hz.

27. What qualities does the "Kevlar like" material used for the rotor have that would prevent damage from flying objects such as birds or airborne debris?

Our experience in large airship structures leads us to use a woven high-tenacity substrate similar to Kevlar. This woven material is coated or laminated with a Tedlar outer surface which reduces abrasion and protects against UV radiation. Tedlar is typically used as a coating on aluminum siding. On the inside of the woven material is a coating designed to act as a gas barrier (Mylar is used as example). It should be noted that the woven substrate material is the same as that used in bullet-proof vests.

28. What happens if a MARS unit breaks loose from the tether?

Magenn has incorporated an instant deflate device if the MARS unit breaks loose from the tether or base (a requirement of FAA). A rip cord type device cuts a hole In the envelope and the MARS unit safely floats back to the ground.

29. Is there a point where the device has to be reeled in to avoid too strong a wind or bad weather?

Yes, in extremely high winds the device should be reeled in and winched down to the ground.

30. What warranty or guarantee will you have on the MARS?

Magenn will pass on the standard warranty for the generators installed. The warranty for the MARS unit will be a minimum of one year. It is expected that a service/support contract will also be sold with each MARS unit (7 to 15% of initial cost per annum). The support contract will cover most mechanical and electrical problems.

31. How soon will backpack-sized units be available?

Backpack size or small units may be available in five to ten years. Magenn Power is looking to license this technology and may not manufacture it ourselves.

32. Can I get a Demo unit for a very large customer?

Demo units are NOT available yet. Magenn Power will have demo units available in 2009/10.

33. Can I be a test site for your MARS unit?

Although test sites are welcome, we have already selected all the test sites we need at this time. Please advice us if you would like Magenn to consider you as a candidate for future test sites.

34. What is the pricing of the MARS 10 kW unit and what does it include?

Final pricing is yet to be determined on the 10kW MARS unit. We are aiming to have Magenn's target list price between $3 dollars to $5 dollars per watt. (Please Note: this price is subject to change).

The MARS 10 kW units includes:

30' x 60' foot envelope (exact size yet to be determined)

Two x 5kW generators, gear systems, etc.

Tether System, 400 feet included, (optional tether lengths will be available up to 1,000 feet at an additional charge)

Necessary lighting on the Tether to meet FAA & Transport Canada regulations
Safety mechanisms in case envelopes detaches from tether to meet FAA & Transport Canada regulations

Onboard Electronics

5 Year warranty on parts and labor, does not include helium

Yearly Maintenance contracts will be available from Certified Dealers and Distributors for an additional fee of (7 to 15%) per year. Magenn Power will supply the parts, and the Dealers will supply the labor.

Not included with the MARS 10kW unit:

Electric Winch (Magenn will provide at an additional charge, but will be offered as a separate line item)

Inverter if required (Magenn will provide at an additional charge, and will be offered as a separate line item)

Necessary Permits will vary from location to location (Certified Dealers and Distributors will be responsible for obtaining permits for most customers)

Installation and setup of the MARS unit (Available from Certified Dealers and Distributors and an extra charge)

Helium (Magenn is negotiating a world price, see question on Helium below for costs)

Electrical cable from MARS unit to power grid or battery system (Available from Certified Dealers and Distributors at an extra charge, Magenn will provide specifications)

Electronics to connect to power grid (Available from Certified Dealers and Distributors for an extra charge, Magenn will provide specifications)

Batteries (Available from Certified Dealers and Distributors for an extra charge, Magenn will provide specifications)

35. What is the size of MARS and its shipping weight?

The MARS 10 kW unit will be approximately 25" x 65" when inflated, it will come standard with a 400 foot tether; this configuration will have a shipping weight under 1,200 lbs.

36. Can I purchase a 10kW unit with a longer tether than 400 feet?

Yes, different tether lengths will be available as an option.

37. Does my customer need a concrete pad for MARS?

Some customers may require a concrete pad for a permanent installation. Magenn Power will provide specifications.

38. How much Helium does the 10kW MARS require?

The exact amount is yet to be determined. MARS 10kW unit will require slightly over 32,000 cubic feet of helium. Please note; Helium is NOT included in the price of MARS units.

39. What is the price of Helium?

The price of Helium varies from country to country. It is roughly $0.30 cents per cubic foot (depending on location in the world). It should be noted that Magenn is negotiating with the worlds largest helium suppliers to get the best available pricing for its distributors and dealers around the world.

40. I hear that Helium leaks?

Yes, Helium will leak over time. Helium leaks at a rate of 0.5% per month or 6% per year, therefore the MARS units will have to be topped up with Helium every 4 to 6 months. The Certified Dealer will provide this service to the consumer.

41. My customer needs to know exact power curves on the 10kW MARS?

Exact power curves and efficiency data are not available at this time. Magenn will provide our findings as soon as they are available. Estimates of power curves and efficiency data estimates are available on the MARS 10 kW specification sheet which is available for download on this site.

42. How do I know if the wind conditions in my area are good for the MARS unit?

MARS units will operate between 2 meters/sec and in excess of 28 meters/sec. As a reseller or Certified Distributor, you will be responsible for knowing your local wind conditions. A Google search should be able to provide you with this data.

43. What permits will I need for my customer?

Each MARS units will need special permits from the FAA to be installed in North America, countries outside of North America may have different rules and may not require permits, please check with your local authorities.

44. What are the exact FAA rules?

See: http://www.chem.hawaii.edu/uham/part101.html

MARS units cannot be installed within 5 miles of an airport; MARS units cannot be installed within a flight path in North America; MARS units must and will have lighting every 50 feet, and the lights must flash once per second. All MARS units must and will have a mechanism to quickly deflate in case a unit gets detached from its tether.

45. What about installing a unit at my house in town?

MARS units will not be able to be installed within most city or town boundaries within North America.

46. I am a very large distributor and I want exclusivity for my country?
At this time, Magenn Power has no plans of offering exclusivity in any one country or geographical area.
Exclusivity may be given to companies that invest in Magenn, do joint ventures with Magenn, license Magenn's technology, or commit to large volumes of MARS product.

47. How do I invest in Magenn Power Inc., how much is Magenn raising and what is the minimum that I can invest?

See Magenn Investment Page. Send an email to invest@magenn.com