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- historical references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
The 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.
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
traction (as the one of
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.
an innovative project which was developed by a group of Engineers from
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.
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
You can see a film on Youtube at the address:
Flying Electric Generator
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 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:
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
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
are interdicted to the flight and, as explained in the Sky Wind Power
the presence of aerostatic balloons in the borders
- 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
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.
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.
For additional information send an email to: gianni.vergnano _at_ sequoia.it