WO2020089330A1

WO2020089330A1 - Wind energy power supply system

Info

Publication number: WO2020089330A1
Application number: PCT/EP2019/079722
Authority: WO
Inventors: René Jozef TIMMERMAN; Yvon Erwin Nicolas TIMMERMAN
Original assignee: Timmerman Rene Jozef; Timmerman Yvon Erwin Nicolas
Priority date: 2018-10-31
Filing date: 2019-10-30
Publication date: 2020-05-07
Also published as: TW202035857A; EP3874160A1; BE1026756A1; BE1026756B1

Abstract

Wind energy power supply system comprising a plurality of wind turbines of a vertical axis type including a vertical rotational axis to which at least one blade is connected, and around which rotational axis said at least one blade is arranged to rotate during use, wherein the wind turbines are mechanically interconnected with each other in such a way that every second wind turbine is arranged to rotate in a first rotational direction, and that any other wind turbine of the system is arranged to rotate in a second rotational direction which is opposite to the first rotational direction.

Description

Title: Wind energy power supply system

The invention relates to a wind energy power supply system.

Such systems are known and generally comprise one or more wind turbines which are arranged to transform wind energy into electric power which can be fed into the electric grid. Wind turbines can for example have a substantially horizontal rotor axis, to which radially extending blades, for example two or three blades, are connected. The main rotor shaft of such wind turbines is located on top of a relatively tall tower. These horizontal axis wind turbines are often grouped together in wind turbine farms, off shore or on shore, and produce the majority of electric power generated by wind today.

In some areas, it may however be relatively inconvenient to install these relatively large wind turbines, such as for example in city centres.

Also in many relatively remote areas, such as islands, power supply remains relatively difficult. Islands may not be connected to an electrical grid at all and/or may still rely on electric generators powered by fuel. Power supplied by alternative energy supplies, such as for example solar energy, may not be sufficient to cover the demand in energy, for example during the night when there is no solar energy. In some areas, wind speeds may temporarily reach too high peak values, for example in hurricane- or typhoon- sensitive regions between the tropical circles, so that blades of wind turbines, or even the entire tower may be destructed. In remote areas, the construction of large wind turbines may also be relatively difficult in terms of logistics, because of relatively large distances. Some of these issues may be addressed by the use of another type of wind turbine, in particular wind turbines having a substantially vertical rotor axis to which one or more blades are connected. These so-called vertical axis wind turbines may be made relatively small. However, an important drawback of these wind turbines is their relatively low efficiency in generating power. Moreover, they often suffer from sagging of blades, leading to a relatively quick wear of the wind turbines.

It is an aim of the present invention to solve or alleviate one or more of the above-mentioned problems. Particularly, the invention aims at providing a more efficient wind energy power supply system which can be installed relatively easy.

To this aim, according to a first aspect of the present invention, there is provided a wind energy power supply system characterized by the features of claim 1. In particular, the wind energy power supply system according to the invention comprises a plurality of wind turbines of a vertical axis type including a vertical rotational axis to which at least one blade is connected, and around which rotational axis said at least one blade is arranged to rotate during use. The wind turbines can for example be of a Savonius type, or a twisted Savonius type, or of a Darrieus type, or of any other type of vertical axis wind turbine. At least one blade, but preferably a plurality of blades, is connected to the rotational axis, for example two, three, four or more blades. The wind turbines are mechanically

interconnected with each other in such a way that every second wind turbine is arranged to rotate in a first rotational direction, and that any other wind turbine of the system is arranged to rotate in a second rotational direction which is opposite to the first rotational direction. In other words, the wind turbines are preferably positioned in such a way that adjacent wind turbines are arranged to rotate in opposite directions. The mechanical interconnection between the wind turbines can for example be realized by a chain being twined as an eight between each pair of adjacent wind turbines. Also other interconnecting means are possible, such as a belt, a rack-and- pinion system, or other known interconnecting means. In an inventive way, the system further comprises a rigging system including at least one tensionable element extending between a lower outer end of the at least one blade and an upper point near the rotational axis of the wind turbine. The rigging system can preferably include at least one tensionable element per blade. In this way, sagging of the at least one blade can be prevented, which can thus increase a lifetime of the system due to reduced material stress. At the same time, the rigging system can allow an increase in a size of the at least one blade, leading to an increase in energy which can be generated by the system. Moreover, the rigging system can improve alignment and synchronization of the wind turbines during use.

The plurality of wind turbines may preferably be Savonius type wind turbines, which can be made relatively compact.

It is preferred that the wind energy power supply system may further comprise a housing, in which the plurality of wind turbines are mounted, which may be regarded as an invention on its own. Such a housing can for example have the shape and/or size of a nominal intermodal 20-foot or 40-foot container, so that the system can be easily transported. Other shapes and sizes are possible as well. The housing can include a bottom side, one or more side panels, and for example one or more top panels. The housing may for example have a box-like shape so that the wind turbines may be placed substantially in a row, but other shapes of housing, such as for example a round shape, as well as different mounting patterns for the wind turbines are feasible as well.

Such a housing can advantageously include side panels which are movable between an open position, in which the wind turbines are exposed to wind, and a closed position, in which the wind turbines are closed off from wind. In this way, by bringing the side panels to a closed position, the wind turbines can be protected against too high wind speeds which might destroy the wind turbines. At the same time, the housing with the side panels in a closed position can protect the wind turbine system during transport. As an additional advantage, the side panels may be brought into an open position in which the side panels can direct air flow towards the wind turbine blades. The side panels may for example be hingedly connected to the housing, for example by a hinge in a substantially vertical direction, or more preferably, by a hinge in a substantially horizontal direction, still more preferably a hinge between a side panel and a top side of the housing. The panels may be openable one by one, or the system may include a synchronization module arranged to move at least two, or preferably all, of the side panels between and open and a closed position in a synchronous way, in order to avoid an unequal load on the plurality of wind turbines, of which some might already be exposed to wind while others might still be closed off from any wind.

In an advantageous way, the housing may be provided with solar panels, preferably with photovoltaic solar panels. In this way, additional power may be provided, for example into a grid, or to a user, or to an energy storage device, such as a battery. When for example a side panel of the housing is in an open position, especially when said side panel is hingedly connected with an upper side of the housing, a first side of the side panel may be provided with solar panels while the opposite side of the side panel may be arranged to direct air flow to the wind turbines, thus optimizing power efficiency of the system while keeping the system relatively compact.

The system can further comprise a transmission system. The transmission system can include a pump per wind turbine, or a pump per set of wind turbines, the set including at least two wind turbines arranged to rotate in opposite rotational directions, which may be considered as an invention of its own. In other words, each set of wind turbines including at least two wind turbines rotating in opposite rotational directions during use, may be connected to a pump of the transmission system. By mounting the wind turbines in this way, efficiency of the energy output of the system can be improved. At the same time, the number of pumps in the system may be reduced to at least half of the number of wind turbines, which can provide a simplified system and hence a reduction in manufacturing costs.

Alternatively, every wind turbine may be connected to one or more pumps. The transmission system may preferably be a water hydraulic transmission system. Water hydraulics can provide a relatively reliable transmission system without a need for oil supply, thus resulting in a relatively environment-friendly transmission system. As an additional advantage, a water hydraulics transmission system may be directly connected to a further hydraulic machine without the need to transform hydraulic energy into electricity. However, alternatively, hydraulic transmission systems based on oil might be used as well.

The wind energy power supply system may further comprise a generator arranged to transform energy transmitted by the energy transmission system into electric energy. Electric power generated by the generator can for example be fed into a grid, or can be fed directly into an electric machine, or can be stored in an energy storage device, such as a battery. In this way, power can be supplied to areas where grid connection may be difficult or inexistent while avoiding to be dependent on fuel supply to drive the generator.

The wind energy power supply system may for example further comprise an integrated water purification unit connected to the energy transmission system. The purification unit may be directly connected to the energy transmission system, for example with a water hydraulic energy transmission system, or may be connected to the energy transmission system via a generator arranged to transform energy transmitted by the energy transmission system into electric energy. For example on remote islands, there may be a relatively high demand of purified, for example at least desalinated, water while the process of purification and/or desalination may require a relatively high amount of power. By integrating a water purification unit into the power supply system, a relatively compact system is obtained which can be transported and installed to bring purified water to users, thus being able to provide for basic needs of remote areas, for example after power cut-offs due to for example natural disasters, or in relatively remote areas.

In an advantageous way, the wind energy power supply system can further comprise a floating platform, wherein the plurality of wind turbines are mounted on said floating platform. In this way, the system can be installed very rapidly and easily, for example in a harbor, just by mooring the platform, without for example the need for any permit for the use of land on which to install the wind turbines.

In case of such a floating wind energy power supply system, the system might further comprise a wave and/or tidal energy converter, the choice between tidal or wave energy depending among other factors on the site where the system is to be used. Such a wave and/or tidal energy converter may provide additional power in a relatively environmentally- friendly way.

Advantageously, the wind turbines may be mechanically

interconnected with each other in such a way that the at least one blade of a first wind turbine is arranged to rotate with a predetermined lag with respect to the at least one blade of an adjacent wind turbine. In case of wind turbines with two blades, blades of adjacent wind turbines may for example be arranged to rotate with a lag of substantially 90 degrees or more or less between the radial extensions of a blade of the first wind turbine and a blade of an adjacent wind turbine. In case of more blades per wind turbine, the lag may be chosen to be smaller. As a result, blades of adjacent wind turbines never point to the same radial direction while rotating. When wind turbines are positioned closely to each other, the predetermined lag in rotation between adjacent wind turbines avoids crushing of the blades into each other.

It is also preferred that the plurality of wind turbines are positioned in such a way that a turning circle of a wind turbine overlaps with a turning circle of an adjacent wind turbine. The wording‘turning circle’ is meant to designate the space the at least one blade of the wind turbine goes through when in rotation. When a distance between a vertical rotational axis of a first wind turbine and a vertical rotational axis of an adjacent wind turbine is smaller than twice a radial width of the at least one blade of the wind turbine, then these turning circles of two adjacent wind turbines at least partly overlap. In this way, a more compact system can be obtained. At the same time, if this is applied to all of the adjacent wind turbines of the system, the efficiency of the system can be increased as the plurality of wind turbines can form a substantially uninterrupted wall of wind turbines, through which wind cannot pass without impacting on the system.

According to a second aspect of the present invention, there is provided a wind energy power supply system characterized by the features of claim 14. Such a system can provide one or more of the above-mentioned advantages.

According to a third aspect of the invention, there is provided a wind energy power supply system characterized by the features of claim 26. Such a system can provide one or more of the above-mentioned advantages.

The present invention will be further elucidated with reference to figures of exemplary embodiments. Corresponding elements are designated with corresponding reference signs.

Figure 1 shows a schematic perspective view on a first embodiment of a wind energy power supply system according to the invention;

Figure 2 shows a schematic perspective view on a wind turbine of the wind energy power supply system of Figure 1;

Figure 3 shows a schematic top view of second embodiment of a wind energy power supply system according to the invention;

Figure 4 shows a schematic view of an interconnection mechanism in the embodiment of Figure 3; Figure 5 shows a plot of total torque in a pump of the preferred embodiment of Figure 4;

Figure 6 shows a schematic side view on the embodiment of Figure

3;

Figure 7 shows a perspective view on a third embodiment of a wind energy power supply system according to the invention;

Figure 8 shows a schematic side view on the embodiment of Figure

7;

Figure 9 shows a schematic side view on a fourth embodiment of a wind energy power supply system according to the invention.

Figure 1 shows a schematic front view on a preferred embodiment of a wind energy power supply system according to the invention. The system 1 includes a plurality of wind turbines 2 of a vertical axis type, for example, but not limited to, of a Savonius type. Each wind turbine 2 includes a vertical rotational axis 3 to which two blades 4 are connected, and around which rotational axis 3 said two blades 4 are arranged to rotate during use. In this specific embodiment, contrary to the embodiments shown in the following figures, instead of having blades 4 extending along a substantially entire length or height of the rotational axis 3, two wind turbines 2a, 2b have been stacked one on top of the other while sharing the same rotational axis 3. Five rotational axes 3 are spaced-apart at equal distances along a single line. The blades 4 can have a curved shape, forming a sort of convex scoop around and spaced-apart from the rotational axis 3, with a flange linking the blade 4 to the rotational axis 3. In this

embodiment, the blades 4 may be curved in one direction only, i.e. around an axis in parallel with the rotational axis 3, and may not present any curvature in any other direction. In other words, a cross-section of the blades in a direction transverse to the rotational axis 3, the blades 4 substantially have a C-shape, while a cross-section of the blade 4 in parallel with the rotational axis 3 may be a substantially straight line. In other embodiments, the blades may show a curvature in all directions. They may for example be manufactured from plastic, such as for example ABS or fiber reinforced plastic, or any other kind of suitable plastic known to the person skilled in the art. In order to improve the stability of the blades 4, an upper side and/or a lower side of the blades 4 may be covered by covering plates 5. In case of a stack of wind turbines on a same rotational axis 3, the blades 4 of a first wind turbine 2a may be mounted with an offset of for example a quarter of a turn with respect to the blades of a second wind turbine 2b. As a result, when a stack of wind turbines on a same rotational axis is rotating, there will always be a predetermined time lag between a passage of the at least one blade of the different stacked wind turbines. In an analogous way, it is preferred to mount the at least one blade 4 of adjacent wind turbines in such a way that there is a rotational lag between said blades when rotating. In other embodiments, instead of two blades, the wind turbine could also include only one blade, even if it is less stable, or three or more blades, which can make the wind turbine self- starting, but may be more difficult in synchronization. Wind turbines may be stacked or not.

Figure 2 shows a schematic perspective view on a wind turbine of the wind energy power supply system of Figure 1. As described for Figure 1, the wind turbine 2, for example of a Savonius type, includes a vertical rotational axis 3 to which two blades 4 are connected, and around which rotational axis 3 said two blades 4 are arranged to rotate during use. Along a cross-section of the blades in a direction transverse to the rotational axis 3, the blades 4 substantially have a C-shape, while a cross-section of the blade 4 in parallel with the rotational axis 3 may be a substantially straight line. An upper side and/or a lower side of the blades 4 may be covered by covering plates 5. In an inventive way, the wind energy power supply system comprises a rigging system including at least one tensionable element 28 extending between a lower outer end 29 of the at least one blade 4 and an upper point near the rotational axis 3 of the wind turbine 2. It is preferred that the rigging system preferably includes at least one

tensionable element 28 per blade 4. The at least one tensionable element 28 may for example be a tensionable cable or a tensionable rod, preferably made of stainless steel for outdoor use. Other materials are pfeasible as well. Additionally, the rigging system may for example include D- shackles to adjust tension in the tensionable element 28. Tension may also be adjusted in other possible ways. A first end of the at least one tensionable element 28 may be connected to the lower outer end 29 of a first blade 4a, for example via an eyebolt, which may be attached to a vertical part or outer end of the blade itself, or to the substantially horizontal covering plate 5 very close to the vertical part of the blade. In an analogous way, a second end of the at least one tensionable element 28 may be connected to an upper point 30 near the rotational axis 3 of the wind turbine 2. Said upper point 30 may be for example be located at an upper inner end of a second blade 4b of the wind turbine, on a vertical part or inner end 31 of said second blade 4b, or on an upper covering plate 5. It may also be located on a flange linking the at least one blade to the rotational axis 3. In case of relatively large blades, the rigging system may include a plurality of tensionable elements per blade, which may each extend between a lower outer end of the at least one blade, and a plurality of upper points near the rotational axis 3 of the wind turbine, the plurality of upper points being spread over for example a height of an inner end 31 of a second blade 4b. In case of three or more blades, the tensioning element may extend between a lower outer end of a first blade and an upper inner end of a neighbouring blade.

Figure 3 shows a schematic top view of second embodiment of a wind energy power supply system according to the invention. Contrary to the previous embodiment, the present embodiment includes six rotational axes 3 in a row instead of five. The wind turbines are mechanically interconnected with each other in such a way that every second wind turbine is arranged to rotate in a first rotational direction 6, for example in a counter-clockwise direction, while any other wind turbine of the system, in particular any wind turbine positioned in between two wind turbines arranged to rotate in said first rotational direction 6, is arranged to rotate in a second rotational direction 7 which is opposite to the first rotational direction 6, for example in a clockwise direction. At the same time, a curvature of the blades 4 a first wind turbine 2 arranged to rotate in a first rotational direction 6 may therefore be a reflection of a curvature of the blades of a directly adjacent wind turbine arranged to rotate in the second rotational direction 7. When considering a line 4c linking the tips of the two blades 4 of a wind turbine 2, then the wind turbines 2 are mounted and interconnected with each other in such a way that there is a lag of substantially 90 degrees between lines 4c linking these tips of blades 4 between adjacent wind turbines 2. It is further preferred that the plurality of wind turbines 2 are positioned in such a way that a turning circle 8 of a wind turbine 2 overlaps with a turning circle 8 of an adjacent wind turbine, as is shown in Figure 3. This result may be obtained when a distance between the rotational axes 3 of two adjacent wind turbines 2 is smaller than a sum of a radius of a turning circle 8 of a first wind turbine and a radius of a turning circle 8 of a directly adjacent wind turbine 2.

Figure 4 shows a schematic view of an interconnection mechanism for the embodiment of Figure 3. The wind turbines are mechanically interconnected with each other in such a way as to obtain the system as explained under Figure 3, with adjacent wind turbines arranged to rotate in opposite directions. This mechanical interconnection 9 may for example be embodied as an endless chain 10 engaging a gear wheel 11 connected to a rotational axis 3 of a wind turbine 2, the chain being wound between adjacent rotational axes 3 in a shape of number eight. Instead of a chain 10, other mechanical interconnections 9 are possible, as will be clear to the person skilled in the art. The mechanical interconnection 9 is preferably arranged to synchronize movement of all the wind turbines 2 of the system 1, in order to avoid that due to differential forces on the various blades, the blades crush into each other, especially in the case in which the wind turbines 2 are positioned as illustrated in Figures 1 and 3, i.e. with overlapping turning circles 8. Said synchronization may for example be provided by a plurality of gear wheels 17 mounted on a synchronization axis 18. The system 1 further comprises an energy transmission system 12 arranged to transmit energy generated by rotation of the wind turbines to an output, e.g. one or more machine needing energy, which machine may be internal or external to the system. The energy transmission system 12 may for example be a hydraulic system, preferably a water hydraulic system. In an inventive way, the energy transmission system 12 may include a pump 13 per set of wind turbines 2, the set including at least two wind turbines 2 arranged to rotate in opposite rotational directions 6, 7. In case of a stack of wind turbines on a same rotational axis, as shown in Figure 1, a pump 13 may be installed per set of oppositely rotating rotational axes 3, implying that for example four or six or more wind turbines 2 may be connected to a single pump. The pump 13 is arranged to increase pressure on a fluidum of the energy transmission system 12, and is preferably positioned between a source of energy, e.g. mechanical energy provided by the rotation of the wind turbines 2, and an output. The system 1 can for example further comprise a motor/generator 14 arranged to transform energy transmitted by the energy transmission system 12 into electric energy. The system may further also comprise an alternator 15 coupled to said motor/generator 14. The

motor/generator 14, or any other output of the system, is fed by a single supply of high pressure fluidum, which is a sum of pressure generated by all individual pumps of the system. So there may not be a single pump per output, but rather a series of pumps working in parallel supplying high pressure fluidum to an output of the system. This output need not be a generator, but may for example be a water purification unit which can be directly connected to the high pressure supply. Other outputs are possible as well. One of the advantages of the system having a pump 13 per set of wind turbines 2 arranged to rotate in opposite rotational directions 6, 7 is illustrated in Figure 5.

Figure 5 shows a plot of total torque in a pump of the preferred embodiment of Figure 4. In Figure 5, torque generated by a first and a second oppositely rotating wind turbine is plotted in function of time. If every wind turbine were individually connected to a corresponding pump, then there would periodically be points without generated torque in each of the pumps. By coupling a set of oppositely rotating wind turbines 2 to a single pump 13, torque can vary periodically but never reaches zero, which can improve the efficiency of the system.

Figure 6 shows a schematic side view on the embodiment of Figure 3. In this embodiment, the two blades 4a and 4b extend along substantially an entire height or length of the rotational axis 3, which extends between an upper bearing 19a and a lower bearing 19b. The mechanical interconnection mechanism 9 including the synchronization axis 18 and the corresponding bearings 17 may be positioned between the lower bearing 19b and a synchronization bearing 20. Pumps 13 may be connected to said

synchronization axis 18 via a planetary gearbox 21, which is arranged to increase a rotational speed of the input into the pump 13.

Figure 7 shows a perspective view on a third embodiment of a wind energy power supply system according to the invention. In an inventive way, the system 1 can further comprise a housing 22, in which the plurality of wind turbines 2 are mounted, see for example Figure 8. The housing 22 includes side panels 23 which are movable between an open position, as shown, in which the wind turbines 2 are exposed to wind, and a closed position, in which the wind turbines 2 are closed off from wind. The housing 22 can for example have the shape and size of a container, for example of a regular container, such as a 20ft or 40ft container, or more preferably of a high cube sea container to facilitate shipping and/or transport of the system to destination. Other shapes and/or sizes of housing are possible as well. For example, when the system is to be mounted on top of a building, the housing may be a lot larger, as also the wind turbines may be made higher. In order to protect the wind turbines against tampering, and at the same time, to ensure safety of people, the housing 22 may be additionally provided with a protective shield 24 which is transparent to wind, such as a wire mesh, or any other screen or fence, as long as it lets wind pass through. The housing 22, in particular an outer side of the side panels 23, may preferably be provided with solar panels 25, preferably with photovoltaic solar panels. This may be especially advantageous, in case the system 1 further comprises an integrated water purification unit (not shown) connected to the energy transmission system 12. Water purification, in particular water desalination, may require a substantial amount of electric energy, which may be at least partly provided by photovoltaic panels, preferably in combination with energy provided by wind energy. However, also other applications are possible, as will be clear to the person skilled in the art.

The solar panels can increase the efficiency of the system in providing additional (electric) energy without making the system more bulky.

Figure 8 shows a schematic side view on the embodiment of Figure 7. The energy provision of the system can be further optimized by carefully positioning the side panels 23 in the open position. Not only can the orientation of the solar panels 25 on an outer side of the side panels 23 enhance energy efficiency of the system, but also the orientation of an inner side 26 of the side panels in an open position may contribute to this aim in that the inner side 26 of the panels may function as wind funnels to redirect wind towards the wind turbines 2. As soon as winds become too strong, the side panels 23 may close off part or all of the wind turbines 2 to protect them from damage. The housing 22 may be subdivided in a first part 22a in which the wind turbines 2 are mounted, and which can be exposed to wind by opening said side panels 23, and in a second part, in which for example the interconnection mechanism and the energy transmission system are being housed, which second part can remain shut off from wind impact. Also other devices which may be part of the system, such as a motor/generator, an alternator, a water purification unit, etc. may be housed in this second part 22b. The second part 22b of the housing 22 is preferably located underneath the first part 22a, but might also be positioned elsewhere, for example on top of the first part 22a. Other subdivisions may also be possible.

Figure 9 shows a schematic side view on a fourth embodiment of a wind energy power supply system according to the invention. The system 1 can further comprise a floating platform 27, wherein the plurality of wind turbines 2 are mounted on said floating platform 27. In case the wind turbines 2 are mounted in a housing 22, the second part 22b may be positioned above the floating platform or inside said platform 27. Thanks to such a floating platform, the system 1 is relatively easily usable on islands. To further exploit the naturally present energy and enhance the energy efficiency of the system, the system 1 could further comprise a wave and/or tidal energy converter (not shown).

For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include

embodiments having combinations of all or some of the features described.

It may be understood that the embodiments shown have the same or similar components, apart from where they are described as being different.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words‘a’ and‘an’ shall not be construed as limited to‘only one’, but instead are used to mean‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage. Many variants will be apparent to the person skilled in the art. All variants are understood to be comprised within the scope of the invention defined in the following claims.

Claims

1. Wind energy power supply system comprising a plurality of wind turbines of a vertical axis type including a vertical rotational axis to which at least one blade is connected, and around which rotational axis said at least one blade is arranged to rotate during use, wherein the wind turbines are mechanically interconnected with each other in such a way that every second wind turbine is arranged to rotate in a first rotational direction, and that any other wind turbine of the system is arranged to rotate in a second rotational direction which is opposite to the first rotational direction, wherein the system further comprises a rigging system including at least one tensionable element extending between a lower outer end of the at least one blade and an upper point near the rotational axis of the wind turbine, wherein the rigging system preferably includes at least one tensionable element per blade.

2. Wind energy power supply system according to claim 1, wherein the plurality of wind turbines are Savonius type wind turbines.

3. Wind energy power supply system according to any of the preceding claims, further comprising a housing, in which the plurality of wind turbines are mounted.

4. Wind energy power supply system according to claim 3, wherein the housing includes side panels which are movable between an open position, in which the wind turbines are exposed to wind, and a closed position, in which the wind turbines are closed off from wind.

5. Wind energy power supply system according to claims 3 or 4, wherein the housing is provided with solar panels, preferably with photovoltaic solar panels.

6. Wind energy power supply system according to any of the preceding claims, wherein the system further comprises an energy transmission system, wherein the energy transmission system preferably is a water hydraulic transmission system.

7. Wind energy power supply system according to claim 6, wherein the energy transmission system includes a pump per wind turbine or a pump per set of wind turbines, the set including at least two wind turbines arranged to rotate in opposite rotational directions.

8. Wind energy power supply system according to any of the preceding claims 6-7, further comprising a generator arranged to transform energy transmitted by the energy transmission system into electric energy.

9. Wind energy power supply system according to any of the preceding claims, further comprising an integrated water purification unit connected to the energy transmission system.

10. Wind energy power supply system according to any of the preceding claims, further comprising a floating platform, wherein the plurality of wind turbines are mounted on said floating platform.

11. Wind energy power supply system according to claim 10, further comprising a wave and/or tidal energy converter.

12. Wind energy power supply system according to any of the preceding claims, wherein the wind turbines are mechanically

interconnected with each other in such a way that the at least one blade of a first wind turbine is arranged to rotate with a predetermined lag with respect to the at least one blade of an adjacent wind turbine.

13. Wind energy power supply system according to any of the preceding claims, wherein the plurality of wind turbines are positioned in such a way that a turning circle of a wind turbine overlaps with a turning circle of an adjacent wind turbine.

14. Wind energy power supply system comprising a plurality of wind turbines of a vertical axis type including a vertical rotational axis to which at least one blade is connected, and around which rotational axis said at least one blade is arranged to rotate during use, wherein the wind turbines are mechanically interconnected with each other in such a way that every second wind turbine is arranged to rotate in a first rotational direction, and that any other wind turbine of the system is arranged to rotate in a second rotational direction which is opposite to the first rotational direction, wherein the system further comprises a housing, in which the plurality of wind turbines are mounted.

15. Wind energy power supply system according to claim 14, wherein the housing includes side panels which are movable between an open position, in which the wind turbines are exposed to wind, and a closed position, in which the wind turbines are closed off from wind.

16. Wind energy power supply system according to claims 14 or 15, wherein the housing is provided with solar panels, preferably with photovoltaic solar panels.

17. Wind energy power supply system according to any of the preceding claims 14-16, wherein the system further comprises a rigging system including at least one tensionable element extending between a lower outer end of the at least one blade and an upper point near the rotational axis of the wind turbine, wherein the rigging system preferably includes at least one tensionable element per blade.

18. Wind energy power supply system according to any of the preceding claims 14-17, wherein the system further comprises an energy transmission system, preferably a water hydraulic transmission system.

19. Wind energy power supply system according to claim 18, wherein the energy transmission system includes a pump per wind turbine or a pump per set of wind turbines, the set including at least two wind turbines arranged to rotate in opposite rotational directions.

20. Wind energy power supply system according to any of the preceding claims 18-19, further comprising a generator arranged to transform energy transmitted by the energy transmission system into electric energy.

21. Wind energy power supply system according to any of the preceding claims 14-20, further comprising an integrated water purification unit connected to the energy transmission system.

22. Wind energy power supply system according to any of the preceding claims 14-21, further comprising a floating platform, wherein the plurality of wind turbines are mounted on said floating platform.

23. Wind energy power supply system according to claim 22, further comprising a wave and/or tidal energy converter.

24. Wind energy power supply system according to any of the preceding claims 14-23, wherein the wind turbines are mechanically interconnected with each other in such a way that the at least one blade of a first wind turbine is arranged to rotate with a predetermined lag with respect to the at least one blade of an adjacent wind turbine.

25. Wind energy power supply system according to any of the preceding claims 14-24, wherein the plurality of wind turbines are positioned in such a way that a turning circle of a wind turbine overlaps with a turning circle of an adjacent wind turbine.

26. Wind energy power supply system comprising a plurality of wind turbines of a vertical axis type including a vertical rotational axis to which at least one blade is connected, and around which rotational axis said at least one blade is arranged to rotate during use, wherein the wind turbines are mechanically interconnected with each other in such a way that every second wind turbine is arranged to rotate in a first rotational direction, and that any other wind turbine of the system is arranged to rotate in a second rotational direction which is opposite to the first rotational direction, wherein the system further comprises an energy transmission system, wherein the energy transmission system includes a pump per set of wind turbines, the set including at least two wind turbines arranged to rotate in opposite rotational directions.

27. Wind energy power supply system according to claim 26, wherein the energy transmission system is a water hydraulic transmission system.

28. Wind energy power supply system according to any of the preceding claims 26-27, further comprising a housing, in which the plurality of wind turbines are mounted.

29. Wind energy power supply system according to claim 28, wherein the housing includes side panels which are movable between an open position, in which the wind turbines are exposed to wind, and a closed position, in which the wind turbines are closed off from wind.

30. Wind energy power supply system according to claims 28 or 29, wherein the housing is provided with solar panels, preferably with photovoltaic solar panels.

31. Wind energy power supply system according to any of the preceding claims 26-30, further comprising a generator arranged to transform energy transmitted by the energy transmission system into electric energy.

32. Wind energy power supply system according to any of the preceding claims 26-31, further comprising an integrated water purification unit connected to the energy transmission system.

33. Wind energy power supply system according to any of the preceding claims 26-32, further comprising a floating platform, wherein the plurality of wind turbines are mounted on said floating platform.

34. Wind energy power supply system according to claim 33, further comprising a wave and/or tidal energy converter.

35. Wind energy power supply system according to any of the preceding claims 26-34, wherein the wind turbines are mechanically interconnected with each other in such a way that the at least one blade of a first wind turbine is arranged to rotate with a predetermined lag with respect to the at least one blade of an adjacent wind turbine.

36. Wind energy power supply system according to any of the preceding claims 26-35, wherein the plurality of wind turbines are positioned in such a way that a turning circle of a wind turbine overlaps with a turning circle of an adjacent wind turbine.