Energia eolica in quota



Xerces Blue
no profit association


It is estimated that in the wind there is a quantity of energy equal to hundred times the total human energy requirement.

Until now the use of windmills has allowed us to exploit a very small part of this energy, the one finding in the area from 20 to 150 meters in height.

The development of the high altitude wind (where you can find the biggest quantity of wind energy) seems to be very late insomuch as today there are no operative systems yet.

The importance of this resource, that can become very shortly one of the main power sources, seems to be ignored from the European Union which denies its existence a priori without considering it in the research calls for the renewable energies.

For a better and more detailed knowledge of this sector we list below:

-   historical references

-   last innovations

-   main projects

-  problems for the development of the altitude wind energy

Last innovations

The rotary Wing

rotary wing

In 1930 the first flight trials of a system with rotary wings from Telefunken were carried out. The system was studied with the purpose of producing electrical energy exploiting the altitude wind. Once reached 700 meters in height the trial failed because of the build up of electrostatic charges on the interconnection electrical cable.


An innovative and simple mechanical way of transmitting the energy, which is generated at altitude by using new types of fibre cables as showed here follows in the Heli Wind Power project, allows overcoming the obstacles previously met.


Light profiles

Piloting a kite in quick circles allows catching the wind energy from a wider area than the dimensions of the kite itself. This technique is used from the surfers and thanks to automatic systems from the big ships of the Sky Sails project and in many research projects for the wind energy. To simplify the systems of flight control and to avoid the handling of long cables, the Rotokite project is based on the autorotation of light aerodynamic profiles on their axis. This system is so simple that you can imagine small generators even build with some automobile recycled materials and rotary kites sold at about ten euro in countries from the Third World.

                                             The most important projects                                             



The SAIL POWER project that enables the traction of vessels thanks to a sail at altitude represents the highest level of industrialisation that has been reached in the studies for the applications for kite as possible means for producing energy.

In the website http://www.skysails.info you can find a wide documentation of the project and you can see a documentary film of the realised applications that show beyond doubt the big interest in examining the research of the possibilities of taking advantage of the altitude wind.

The extreme manoeuvrability of kites and their profile with characteristics similar to the ones of the wing of an aircraft enables a quick movement and a following catching of energy that is not linked to the dimension of the kite but to the area where it realises its performances.

Kite Wind Generator

Different projects generating energy for traction (as the one of Delft University you can see in the below website) have been developed using the same principle of handling of kites.


Then there is the Kite Gen project for big powers shown in the next picture. Many Kites alternate phases of traction on the arms of a big rotor with recovery phases that allow recovering the position of the beginning of the cycle in the same way as sailboats can sail directly into the wind.




The Rotokite is an innovative project which was developed by a group of Engineers from Turin, promoters of this site.

It uses aerodynamic profiles similar to the ones of kites. These profiles have been rotated on their own axis for emulating the performances of a big propeller at altitude.

The use of the rotation principle simplifies radically the difficult problem of the flight control and eliminates the technical difficulties due to the lengths of cables enabling the production of wind energy at very low costs.

Operation video of the RotoKite

Operation description in a pdf file

The Magenn's project


While the projects presented up to now use a part of the energy for the levitation, the company Magenn, specialised in the construction of modern aerostatic balloons, has realised a prototype that uses light gas for the levitation. See the website  


The rotation of the central body generates lift and powers electric generators that are installed to the sides. The produced energy is transmitted to the ground through an electric cable. The forecast is to realise a system of generation with variable powers from 10 to 1000 kw in the period 2009/16.



A project of Prof. Okels and f students from the University of Delft assumes the production of energy with not moving wings rather than with kites. The aerodynamic profiles, which are similar to a glider without the pilot, alternate rising phases, creating traction on a cable, with recovery phases in which aerodynamic profiles are let get off rapidly by changing their trim.

You can see a film on Youtube at the address:


Flying Electric Generator

ala rotante

The Austrialian Professor Bryan Roberts has realised a prototype of wind generator that has been called Flying Electric Generator (FEG). In this project the previously mentioned generation principle from Telefunken has been taken back.

The project of Prof. Roberts Bryan was given a prize from Time as TIME’S BEST INVENTIONS OF 2008

The project and all problems concerning the energy generation at altitude are well recorded on the website  http://www.skywindpower.com/ww/index.htm

The weight of the structure of catching and transformation of the energy foresees the use in the areas with strong wind or at high altitude.

You can see the flight of the first prototype on Youtube at the address:


The Heli Wind Power

The Heli Wind Power is a project of a group of Engineers from Turin, promoters of this site, which recovers the concept of the Flying Electric Generator and of the prototype from Telefunken introducing two features aimed to lighten the system so that it can produce energy with winds with less intensity.

The project regards from one side the lightening of rotors by using tie-rods and from the other side the mechanical transmission to the ground of the energy which has been generated at altitude.

The recent innovations regarding the field of fibres have permitted to think about a very light closed cable that operating with an innovative system of interconnected pulleys allows the realisation of a very light power transmission at long distances (the missing link of the wind energy).

You can see a summary of the project opening the below file:

Heli wind power


Problems of development of the upper wind


- A problem: the patents

It can be strange but the patents are, in our opinion, the main reason the altitude wind energy has been not developed yet.

The several projects concerning the use of the kites or other enough intuitive techniques with the aim of generating energy have given place to the recording of hundreds of patents, sometimes very general ones but in any case sufficient to permit an action against companies that will invest money for checking the real development possibilities.

In this way the sector is suffering from a background that is completely hostile to the research and the testing because each essay can be affected by a legal action.

The resulting failure of important initiatives of research has given birth to a general scepticism regarding the actual possibilities of the wind generation at altitude without taking into account the technical data and the studies that on the contrary demonstrate the real application possibilities.

- A lack: the attention and the financing of the research for the altitude wind

It is clear that Europe has today a big necessity of developing new technologies that can face the big problem of climatic changes and of the energy production but unfortunately the initiatives that have been taken so far have failed to consider the importance of the problem.

The European Union, even if paladin of the renewable energies, for the wind research finances only the development of what was invented 4500 years ago. We fear that, without any promotion from the outside, it will be necessary long time to take into consideration what was thought in an authoritative way in 1930 and in more recent times.

This site aims to be an invitation for the European Union to think rapidly about the choices taken up today as far as the financing of research is concerned.  

- A false problem: the flight areas

When a project of generation at altitude is presented, the most frequent objection is that this system can be a danger for the flight.

Today all aircrafts are equipped with satellite positioning systems so this means that the delimitation of wind areas or even individual facilities, provided they are properly marked, does not represent a danger for the Air Navigation.

Today there are several areas that are interdicted to the flight and, as explained in the Sky Wind Power project, the presence of aerostatic balloons in the borders USAMexico with the aim of avoiding illegal air transport has never caused accidents.

- A simple calculation: the efficiency of the systems

The altitude wind blows with stronger intensity and continuity compared to the wind on the ground and even the simple observation of the clouds gives evidence of this.

By rising at an altitude of 400/800 meters it is easy to have winds with an intensity that is double compared with those that can be found with a traditional wind generator operating at an average height of 70 meters. By doubling the speed of the wind, the energy will increase with the cube, i.e. eight times.

Furthermore, at altitude, the time for having winds suitable for the energy generation increases. So, it is realistic to foresee at least a doubling of working hours.

We can say approximately that at middle altitudes there is energy equal to at least 16 times the one you can have in a site that is already suitable to the wind generation.

It is clear that, even a less efficiency of wing profiles of the generation systems at altitude, will not be significant, considering the very big increase of available energy.

- A big exemplification: the support facilities

The catching of the altitude wind does not need the realisation of support facilities because all assumptions that have been done so far just determine traction between the link point to the ground or on a vessel and the aerodynamic element at high altitude. The windmills need towers of almost 100 metres in height with significant problems for the foundations and for the structures that are highly stressed.

What above mentioned does not only determine big cost reductions but especially permits to place easily the generators for example on small floating platforms or even in deep waters where it is difficult to intervene with other technologies.

- The environmental impact

The space that is occupied on the ground is extremely reduced compared with the majority of other systems and does not present any problems of acoustic pollution that are common in strongly populated areas.

Furthermore, the possibility of placing the systems of generation at relatively high altitudes can strongly reduce the visual impact.

Even if for the moment we can not do sure estimations on the climatic impact that will be produced from the altitude wind, we think that it causes less problems than the impact produced from the windmills that generate a mixing of the atmospheric stratification next to the ground.


- Looking at the sky: the ubiquity

Looking at the map of winds that blow in Europe at 80 meters in height, you can see as the wind energy at ground can be exploited just in a small part of the territory.


If we increase the altitude, the situation changes completely. And, adding the possibility to operate in the sea, the majority of the earth surface appears suitable for the exploiting of the wind energy.



- Costs

The wind generation on the ground in the winding sites of the North Sea has an estimated cost of 0,06 euro cents each Kw, for sure the lowest cost, without taking into account the hydroelectric one as far as the renewable energies are concerned. It is estimated a cost less than 0,01 euro each Kw for the systems at high altitudes that are simpler as far as facilities and operation are concerned.

In a period of rapid technological growth the low costs for the building of the plant and the following rapid amortisation of the systems of altitude wind energy generation permit them to be replaced with new technologies without any losses.

The low investment capital in the new installations makes this energy source necessary to avoid that the developing countries use highly polluting systems.

- Ideas for the development

There are many systems for the production of energy that can be developed but the generation at high altitudes, despite the exceptional potentialities, seems to be a system with fewer resources for the research and with fewer expectations without any reasons.

The most important obstacles, as already explained, are the privatisation of the research, the concerns for the occupation of the airspace.

The realisation of a valid demonstrative project of wind generation could give birth to perspectives that are unimaginable today.


A big technological competition, recalling the great technological challenges of the last century with the participation of hundreds of researchers and universities, would be less spectacular than the American Cup but less expensive and infinitely more useful. 

The Rotokite and Heli Wind Power projects are open source in all developing countries. In all other countries collaborations are requested whose returns will be used for the spreading of renewable energies and the research.                                            

- Contacts

For additional information send an email to: gianni.vergnano _at_ sequoia.it