Kite Energy, Wind Energy, Clean Energy

Once you start using power kites, you will notice that kites have lots of energy, much more than any other traditional wind power devices (traditional windmill or wind turbine).

Wind power has been proven in the recent decades to be one of the most promising and popular sources of clean energy using traditional devices.  So why not kite energy?

Advantages and Disadvantages of Kite Energy Systems

Many have thought just that in the last couple of years and have discovered that kites have lots more potential than traditional wind power devices:

1. Kites fly higher, therefore have more consistent and cleaner wind
2. Kites do not require massive supporting base tower and platform
3. Kites can fly across the wind window to generate even more power than the wind can provide
4. Multiple kites can be easily stacked for more power

However, kite power generation systems do have their own disadvantages:

1. Kites require launching (after installation/maintenance and after a no wind period) and landing (in case of thunder storm or hurricane).  Wind turbine towers have the same lightning problem during thunderstorm but they do shut off in case of strong wind during hurricane (modern wind turbines normally shut off when the wind reaches 90 km/hr and the whole structure can survive hurricane wind up to 220 km/hr, top range of Category 3 hurricane wind speed)
2. Regulation and safety issues for high flying kites:
   • Not deployable within 5 miles radius of an airport
   • Need Notice to Airmen (NOTAM) from FAA
   • Need lighting every 50 feet along its tether
   • For self-floating kite, need Rapid Deflation Devices that can bring the kite down in case of escape from mooring

   More details of the FAA regulations for kites/balloons can be found at http://www.chem.hawaii.edu/uham/part101.html. 

3. Liability issues for kites landed on other people land.

Kite Energy Products

There are a couple of companies currently trying to enter the kite energy market and main ones are:

1. Skywindpower
2. Magenn
3. Sequoia Automation
4. Briza Technologies

Skywindpower is promoting the Flying Electric Generator (FEG), Magenn is prototyping the Magenn Power Air Rotor System (MARS), Sequoia Automation is introducing the Kite Generator and Briza Technology is aiming for the Hovering Wind Turbine Technolgoy.

Furthermore, there was the Laddermill project introduced in 2003 but apparently there is no new development since September 2003.

Sky WindPower Flying Electric Generator

The Sky WindPower Flying Electric Generator (FEG) is more a flying helicopter than a kite.  It rotating rotors help to fly the FEG and at the same time generate electricity.  The power efficiency will be divided between supporting the kite and generating power.  Furthermore, as the rotor is somewhat inclined, its "effective" swept area is less than that of a comparable wind turbine.  The FEG, however, similar to a helicopter, can fly at high altitude and should be able to offer more consistent and more efficient energy than a comparable wind turbine.

More info regarding the FEG can be found at http://www.skywindpower.com or in this video posted on Youtube.com

Magenn Power Air Rotor System (MARS)

The Magenn MARS is more a blimp than a kite.  It is lighter than air and therefore can float during no-wind periods.  Once launched, the MARS does not have to be landed nor re-launched unless during thunderstorm or hurricane. 

Its body rotate upward creating additional lift (magnus effect) during periods with windy periods.  This is the similar principle used in UFO kites. The rotation of the body can then be used to create electricity as shown in this video posted on Youtube.com:

 
Magenn MARS

MARS is in its early prototype stage and an early prototype is shown flying in this video posted on Youtube.com:

 
MARS Prototype

As stated by Magenn on their web site, "Magenn Air Rotors are 50% as efficient as the best propeller rotors, in terms of their wind intercepted area";  However, as MARS is very scalable, more flexible and can fly at higher altitude than wind turbines, it can offer much better efficiency economic especially in larger units.

More info about MARS can be found at http://magenn.com.

Kite Generator

Kite Generator is a very interesting concept which has a closer root to kitesurfing than any other devices.  It is actually make use of the power of the kite diving flying across the power zone to turn a horizontal structure similar to a merry-go-round (turning around a vertical axis) to create electricity.

The kite flying zone is determine by the position of the kite attachment point (on the merry-go-round) while it rotates around the axis.  The positions are divided into 3 zones: left pull zone, right pull zone and neutral zone.  While the kite is in the left pull zone, it will fly on the left side of the wind window to turn the merry-go-round.  Similarly, the kite will fly in the right wind window to turn the merry-go-round when it is in the right pull zone. When the kite is in neutral zone, it must be kept in neutral, depowered mode such that it would not interfere with the pull of the other kites on the merry-go-round.

One would need a very sophisticated control system to manipulate all these kite flying exercises; however, the trade off is the ability to harness the full power of the wind window which in turn will be able to generate much more electricity than the traditional wind turbines of comparable cost.

The following video posted on Youtube.com shows the operation of the Kite Generator:

Similar to other kite energy devices, there are issues involve with the sophistication of the control of the kites and the launching and landing of the kites after periods of no wind or during thunder storms or hurricanes; however, Kite Generator has lots of potential as it is currently the only energy device that can harness the whole wind window power zone.

More info about the Kite Generator can be found at http://www.kitewindgenerator.com/.

Briza Technologies Hovering Wind Turbine

The Hovering Wind Turbine from Briza Technologies is basically a series of wind turbines (Darrieus turbines with horizontal axis) with blimps situating in the wind shadow area of the turbines to keep the whole structure float during no wind periods.

The Hovering Wind Turbine is very similar to the Magenn MARS with the exception that the turbines and the blimps are not fully integrated as the case of the MARS and therefore need heavy frame to integrate the two structures.  The advantage is that the blimps are behind the turbines and therefore have less drag.

More info about the Hovering Wind Turbine can be found at the Briza Technologies web site http://www.briza-technologies.com/.

Future Kite Energy Products

Until we have a kite energy product in full operations, the jury is still out whether kite energy is as proven as wind turbine.  To be more competitive than the current wind turbine and be practical, a kite energy solution should have one or more of the following characteristics:

1. The kite should float (like the Magenn MARS and the Hovering Wind Turbine) such that no landing nor re-launching is needed during the no-wind periods.  This allows it to operate in an un-supervised fashion similar to wind turbine.
2. The kite should make use the full power of the wind window (like the Kite Generator).  This would make it much more competitive than the current wind turbine.
3. The kite should be "lightning safe" such that it does not need to be landed each time there is a thunderstorm.  While a wind turbine does have similar lightning risk as kites, it is normally lower so has less risk.
4. The kite energy system should be able to accommodate very strong wind (up to 120 km/hr, top range of tropical storm wind speed) during tropical storms (a somewhat frequent occurrence) such that it only needs to be landed for winds more than 120 km/hr during hurricanes (rarer occurrence).  Check http://www.friesian.com/wind.htm for the details of the various wind ranges.  Also check http://www.zephyreco.co.jp/en/main_pro_airdolphin.htm for a modern wind turbine that can operate up to 50 m/s wind speed (180 km/hr or top range of Catergory 2 hurricane wind speed) and there are talks about floating wind turbines that can handle hurricane wind http://www.renewableenergyaccess.com/rea/news/story?id=46025.  Please note that even thought modern wind turbines can survive category 3 hurricanes, most may be damaged in category 4 and especially category 5 hurricanes (such as Katrina).  In the case of a kite, just land it and store it away for the duration of the hurricane.

Related Kite Energy Technology

This technology could be useful to support the heavy cable to conduct electricity from the kite down to earth (a video posted on Youtube.com)

Let us know if you know of any other kite energy or related products.

Reference Info

• Wind Turbine http://www.windmission.dk/workshop/BonusTurbine.pdf