阅读说明：本技术 用于风力涡轮机的基座以及风力涡轮机 (Foundation for a wind turbine and wind turbine ) 是由 J·古尔德 C·洛皮斯 S-M·维克托 于 2020-03-02 设计创作，主要内容包括：本发明涉及一种用于风力涡轮机(2)的基座(1),其包括带有中心区(4)和外部区(5)的基部装置(3),其中所述外部区(5)被配置成用于承载所述风力涡轮机(2)的大部分重量。在所述中心区(4)中,所述基部装置(3)包括室(6),其中所述基座(1)进一步包括能量存储装置(7),其中所述能量存储装置(7)包括枢转地布置在所述室(6)内以用于存储旋转能量的飞轮(8)。所述能量存储装置(7)进一步包括用于将风力涡轮机(2)的能量转化成所述飞轮(8)的旋转能量并且用于将所述飞轮(8)的旋转能量转化成电能的传输装置(9)。本发明进一步涉及一种风力涡轮机(2),并且涉及一种用于存储和使用由风力涡轮机(2)产生的能量的方法。(The invention relates to a foundation (1) for a wind turbine (2), comprising a base device (3) with a central zone (4) and an outer zone (5), wherein the outer zone (5) is configured for carrying a majority of the weight of the wind turbine (2). In the central zone (4), the base device (3) comprises a chamber (6), wherein the base (1) further comprises an energy storage device (7), wherein the energy storage device (7) comprises a flywheel (8) pivotally arranged within the chamber (6) for storing rotational energy. The energy storage device (7) further comprises a transmission device (9) for converting energy of a wind turbine (2) into rotational energy of the flywheel (8) and for converting rotational energy of the flywheel (8) into electrical energy. The invention further relates to a wind turbine (2) and to a method for storing and using energy generated by a wind turbine (2).)

1. A foundation (1) for a wind turbine (2), comprising a base arrangement (3) with a central zone (4) and an outer zone (5), wherein the outer zone (5) is configured to carry all the weight of the wind turbine (2),

it is characterized in that the preparation method is characterized in that,

in the central zone (4), the base means (3) comprise a chamber (6), wherein the base (1) further comprises an energy storage device (7), wherein the energy storage device (7) comprises a flywheel (8) pivotally arranged within the chamber (6) for storing rotational energy, and wherein the energy storage means (7) further comprises transmission means (9) for converting energy of a wind turbine (2) into rotational energy of the flywheel (8) and for converting rotational energy of the flywheel (8) into electrical energy, wherein the transmission device (9) comprises a flywheel electric motor (10) for converting electric energy into rotational energy of the flywheel (8), and wherein the transmission means (9) comprise electric control means (11) for providing electric energy from an electric grid (G) to the flywheel electric motor (10).

2. Susceptor (1) according to claim 1,

It is characterized in that the preparation method is characterized in that,

the transmission device (9) comprises a flywheel generator (12) for converting rotational energy of the flywheel (8) into electrical energy.

3. Susceptor (1) according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the energy storage device (7) comprises a clutch (13) for mechanically decoupling the flywheel (8) from a transmission device (9) of the energy storage device (7).

4. Susceptor (1) according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the energy storage device (7) comprises a magnetic bearing (14) for pivoting the flywheel (8) relative to the chamber (6).

5. Susceptor (1) according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the chamber (6) is configured as a vacuum chamber (6).

6. Susceptor (1) according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the energy storage device (7) comprises a plurality of flywheels (8).

7. Susceptor (1) according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

each flywheel (8) has a cylindrical or at least substantially cylindrical shape.

8. A wind turbine (2) comprising: a rotor (15), the rotor (15) having rotor blades (16) for converting wind energy into rotational energy of the rotor (15); a generator (17) for converting the rotational energy of the rotor (15) into electrical energy; a tower (18) for carrying the rotor (15) and the generator (17); and a foundation (1) for carrying the tower (18),

It is characterized in that the preparation method is characterized in that,

the base (1) is a base (1) according to any one of the preceding claims.

9. A method for storing and using energy generated by a wind turbine (2), comprising the steps of:

-closing a clutch (13) for coupling a flywheel (8) of a base (1) of the wind turbine (2) with a motor rotor (19) of a flywheel electric motor (10) of the base (1),

-providing the flywheel electric motor (10) with electric energy generated by a generator (17) of the wind turbine (2) by means of an electric control device (11) of the base (1),

-operating the flywheel electric motor (10) with the provided electric energy and thereby generating rotational energy of the flywheel (8), and

-driving a flywheel generator (12) by a rotating flywheel (8) for converting the rotational energy of the flywheel (8) into electrical energy,

wherein the electrical energy generated by the flywheel generator (12) is used to drive an electric motor (20) for supporting a rotation of a rotor (15) of the wind turbine (2).

Technical Field

The present invention relates to a foundation for a wind turbine, in particular for an onshore wind turbine. Furthermore, the invention relates to a wind turbine, in particular an onshore wind turbine.

Background

A foundation for a tower of a wind turbine is provided using a foundation for a wind turbine, in particular for an onshore wind turbine. Typically, such foundations are made of concrete, in particular reinforced concrete or the like. These foundations comprise different zones that contribute differently to the support of the tower. Basically, such foundations comprise an outer zone and a central zone, wherein all or at least most of the load of the tower is conducted into the outer zone. Thus, the central zone is also denoted as "unloaded zone".

Typically, the central zone is present only to simplify the design of the base and mounting, but has no specific function due to the lack of load. Thus, the central zone contributes substantially to the environmental footprint as well as the cost of the wind turbine project.

Furthermore, wind turbines have the following disadvantages: in windy conditions, excess power may be generated, wherein in windless conditions, power may not be generated. This means that it is a particular challenge to the grid to transport and store the power generated by the wind turbine.

To reduce the grid burden and provide a more constant supply of power, methods exist for storing power locally at the wind turbine. Documents US 7,608,937B 1 and US 7,265,456B 2 relate to power generation systems with wind turbine generators and batteries for storing excess power and providing this power in windless or low wind speed situations.

Batteries have the disadvantage of relatively high cost and low life due to constant capacity loss. Used batteries are hazardous waste and, therefore, the recycling of batteries is also very expensive. Furthermore, such batteries generally require cooling devices to prevent overheating and must be protected from the environment, in particular from water.

Disclosure of Invention

It is therefore an object of the present invention to provide a device which does not have these disadvantages or at least does not have them. In particular, it is an object of the present invention to provide a foundation for a wind turbine, and a wind turbine providing improved storage of energy generated by the wind turbine.

This object is solved by the patent claims. This object is therefore solved by a foundation for a wind turbine having the features of independent claim 1, by a wind turbine having the features of independent claim 10 and by a method having the features of independent claim 11. Further details of the invention emerge from the dependent claims as well as from the description and the drawings.

According to a first aspect of the invention, the problem is solved by a foundation for a wind turbine comprising a base device with a central zone and an outer zone, wherein the outer zone is configured for carrying a majority of the weight of the wind turbine. According to the invention, in the central area, the base device comprises a chamber, wherein the base further comprises an energy storage device. The energy storage means comprises a flywheel pivotally arranged within the chamber for storing rotational energy and transmission means for converting energy of the wind turbine into rotational energy of the flywheel and for converting rotational energy of the flywheel into electrical energy.

The foundation is configured as a base for a wind turbine, in particular a wind turbine with: a rotor including rotor blades for converting wind energy into rotational energy of the rotor; a generator for converting rotational energy of the rotor into electric energy; and a tower for carrying the rotor and the generator. Thus, the foundation is configured as a base of a tower. Preferably, the foundation comprises fixing means, such as screw holes or the like, for fixing the tower to the foundation.

The outer region of the base unit constitutes a part of the foundation, which is configured to carry all or at least most of the weight of the wind turbine. The base unit or at least the outer region of the base unit is preferably made of or at least substantially made of steel-concrete or the like. According to the invention, the base device and/or the base preferably have a cylindrical or cubic outer geometry. Basically, the outer shape and size of the base may be the same or at least similar to the bases known from the prior art.

The chamber is provided in a central region of the base device. The central region is within an unloaded region of the base. Thus, due to the chamber, there are no structural disadvantages compared to a susceptor not having such a chamber. The chamber is preferably sealed from the environment to prevent moisture from entering the chamber. The inner wall of the chamber preferably has a smooth surface, for example to avoid air turbulence.

The flywheel of the energy storage device is located within the chamber and is pivoted against a wall (e.g., a side wall, floor or the like) of the chamber, particularly by a bearing. Thus, the flywheel can rotate freely inside the chamber. The bearings are preferably configured for minimized friction to minimize loss of rotational energy of the rotating flywheel. The axis of rotation of the flywheel is preferably vertical or horizontal. Alternatively, the axis of rotation of the flywheel may be transverse. The flywheel preferably comprises a material having a relatively high density, such as lead, iron, steel or the like. Preferably, the flywheel is configured as a massive body. The outer surface of the flywheel is preferably relatively smooth to avoid or at least reduce turbulence. Furthermore, the flywheel preferably has a rotationally symmetrical shape. Preferably, the chamber and the flywheel are configured such that a constant, or at least substantially constant, gap is provided between an outer surface of the flywheel and an inner wall of the chamber.

The transmission device of the energy storage device is configured for converting energy, preferably electrical energy, of the wind turbine into rotational energy of the flywheel and for converting rotational energy of the flywheel into electrical energy.

The base according to the invention has the following advantages: energy of the wind turbine can be temporarily stored and provided on demand by means of cost-effective means and in a safe manner. With the present invention, it is possible to manage situations of smooth power output, improving black start, enhancing performance, and providing backup power, for example.

Smooth power output is advantageous because wind tends to blow at different wind speeds and, therefore, the amount of electrical energy that can be produced by the generator of the wind turbine is not constant. By means of the invention, a smoothed power output of the wind turbine may be provided. Smoothing, for example, involves meeting a certain power set point. This means that power above the set point is absorbed when the amount of power generated is above the set point, or power is injected from the storage device when the amount of power generated is below the set point. This applies to all wind speeds. This may be achieved by storing excess energy of the wind turbine in a flywheel or converting the rotational energy of the flywheel into electrical energy as required.

Furthermore, by means of the invention, a black start of the wind turbine may be improved. In order to start the rotor of a wind turbine, inertia, friction and stiction must be overcome. Furthermore, the main application of black start is to provide a current to magnetize the generator coil in order to generate the magnetic field required for induction. Current wind turbines require drawing electrical energy from the grid for starting. By means of the invention, the start-up of the rotor is possible even in situations where sufficient electrical energy is not available in the grid, for example just after a grid power outage.

In addition to this, by means of the invention, backup power for the wind turbine can be provided. Thus, batteries are no longer required.

Preferably, the transmission means comprises a flywheel electric motor for converting electric energy into rotational energy of the flywheel. According to the invention, the transmission means may comprise more than one flywheel electric motor for driving the flywheel when a rapid conversion of electric energy into rotational energy is required, for example for redundancy and/or boost operation. It is further preferred that at least one of the plurality of flywheel electric motors is mechanically decoupled from the flywheel and/or the plurality of electric motors by means of a clutch. The flywheel can be rotated by means of the flywheel electric motor. Thus, it is preferred that the motor rotor of the flywheel electric motor is mechanically coupled or at least can be mechanically coupled to the flywheel. In an alternative embodiment of the invention, the flywheel electric motor may be part of a flywheel. The flywheel electric motor has the following advantages: the conversion of electrical energy into rotational energy of the flywheel can be provided by conventional means and in a cost-effective manner.

Advantageously, the transmission means comprise electric control means for supplying electric energy generated by the generator of the wind turbine and/or electric energy from the grid to the flywheel electric motor. Further preferably, the electrical control means is configured to provide electrical energy from the flywheel generator to an electrical grid. Receiving electrical energy from the generator of the wind turbine for driving the flywheel electric motor has the following advantages: excess electrical energy generated by the generator may be stored as rotational energy. Receiving electrical energy from the grid for driving the flywheel electric motor has the following advantages: by common means and in a cost-effective manner, surplus electrical energy of the grid can be stored as rotational energy. The foundation of a particular wind turbine may still be used to store energy even when the wind turbine is not operating.

According to a preferred embodiment of the invention, the transmission means comprise a flywheel generator for converting rotational energy of the flywheel into electrical energy. Preferably, the flywheel generator and the flywheel electric motor are the same device. This has the following advantages: the investment cost and the operating space can be reduced. Alternatively, the flywheel generator and the flywheel electric motor may be configured as different devices. This has the following advantages: by common means and in a cost-effective manner, the technical characteristics of the flywheel generator and the flywheel electric motor can be optimized with respect to the expected operating parameters. Thus, the flywheel generator and the flywheel electric motor may have different sizes.

Preferably, the energy storage device comprises a clutch for mechanically decoupling the flywheel from the transmission device of the energy storage device. Preferably, the clutch is located between the flywheel and the flywheel electric motor and/or the flywheel generator to mechanically decouple the flywheel electric motor and/or the flywheel generator from the flywheel. It is further preferred that the clutch is configured as a magnetic clutch. The clutch has the following advantages: by conventional means and in a cost-effective manner, the flywheel can rotate freely without being mechanically coupled to the flywheel electric motor and/or the flywheel generator. Thus, the mechanical loss of rotation of the flywheel is reduced and rotational energy can be stored within the flywheel for a longer time.

Preferably, the energy storage means comprises a magnetic bearing for pivoting the flywheel relative to the chamber. The magnetic bearing preferably comprises a permanent magnet and/or a magnetic coil. Preferably, the energy storage device is configured to provide the magnetic coils with electrical energy generated from a generator of a wind turbine and/or a flywheel generator and/or provided from an electrical grid. It is further preferred that the energy storage device comprises a safety bearing to replace the magnetic bearing in case of a technical defect, an electrical outage or the like. The magnetic bearing is preferably supported at the wall and/or bottom of the chamber. The use of magnetic bearings has the following advantages: by ordinary means and in a cost-effective manner, friction in the energy storage device may be reduced and rotational energy may be stored in the flywheel for a longer time.

Advantageously, the chamber is configured as a vacuum chamber. This means that the chamber is configured for being hermetically closed to the environment of the base. It is further preferred that the base comprises a vacuum pump for evacuating the chamber. Preferably, the base comprises a pressure sensor for measuring the pressure inside the vacuum chamber. The pressure sensor is preferably connected to a pump control unit of the vacuum pump for automatically operating the pump in dependence of the measured pressure. The vacuum chamber has the following advantages: by common means and in a cost-effective manner, air resistance and turbulence within the chamber may be reduced and rotational energy may be stored within the flywheel for a longer time.

In a preferred embodiment of the invention, the energy storage means comprises a plurality of flywheels. The flywheel is pivotally disposed within the chamber. Preferably, the flywheels are evenly or symmetrically distributed over the chamber. Preferably, the flywheels are mechanically decoupled from each other and are operable independently of each other. By these means, the size of the flywheel can be significantly smaller than the size of only one flywheel. Thus, the flywheel electric motor and flywheel generator can also be smaller in size. The multiple flywheels have the following advantages: by common means and in a cost-effective manner, the storage of energy can be improved.

Preferably, each flywheel has a cylindrical or at least substantially cylindrical shape. The substantially cylindrical shape is a cylindrical shape having one or more distinct regions, for example, for coupling with a bearing. This has the following advantages: by common means and in a cost-effective manner, a flywheel is provided which has particularly good rotational properties and which can be easily fitted into the chamber of the base.

According to a second aspect of the invention, the problem is solved by a wind turbine comprising: a rotor with rotor blades for converting wind energy into rotational energy of the rotor; a generator for converting rotational energy of the rotor into electric energy; a tower for carrying the rotor and the generator; and a foundation for carrying the tower. According to the invention, the base is a base according to the first aspect of the invention.

The rotor and the generator are preferably arranged within a rotor chamber which is pivotally arranged at the top end of the tower. The rotor is pivotally disposed within the rotor chamber. The rotor blades are attached to the rotor and are preferably arranged pivotally at the rotor for adjusting the rotor blade setting angle of the rotor blades relative to the rotor.

Preferably, the tower is configured to have a hollow configuration of a substantially cylindrical or conical shape. The lower part of the tower preferably has a larger diameter than the upper part of the tower. The tower may be composed of more tower sections, which may be connected to each other by fasteners such as screws, nuts and bolts, welds or the like. The tower is configured for carrying the rotor and the generator, in particular for carrying the rotor chamber.

The wind turbine according to the invention has the same advantages as the foundation according to the first aspect of the invention. Thus, the wind turbine has the following advantages: the electrical energy generated by the generator can be temporarily stored by the energy storage device and provided on demand, by means of cost-effective means and in a safe manner. With the present invention, it is possible to manage situations of smooth power output, improving black start, enhancing performance, and providing backup power, for example.

According to a third aspect of the invention, the problem is solved by a method for storing and using energy generated by a wind turbine, in particular a wind turbine according to the second aspect of the invention. The method comprises the following steps:

-closing a clutch for coupling a flywheel of a foundation of the wind turbine with a motor rotor of a flywheel electric motor of the foundation,

-providing electrical energy generated by a generator of a wind turbine to a flywheel electric motor by means of electrical control means of the base,

-operating the flywheel electric motor by means of the supplied electric energy and thereby generating rotational energy of the flywheel, and

-driving a flywheel generator by the rotating flywheel for converting the rotational energy of the flywheel into electrical energy.

In an initial step, the clutch, in particular the magnetic clutch, is closed. By closing the clutch, the flywheel of the base of the wind turbine is mechanically coupled with the motor rotor of the flywheel electric motor of the base. With the clutch closed, the rotational speeds of the flywheel electric motor and the flywheel are within a predetermined compliance ratio.

Wind blows at a certain wind speed or at various wind speeds onto the rotor blades of the rotor of the wind turbine. This causes the rotor to rotate. This causes the generator to produce electrical energy, since the rotor and generator are mechanically coupled to each other. At least a portion of this electrical energy is provided to the flywheel electric motor, especially when the capacity of the grid is at its limit.

By supplying electrical energy to the flywheel electric motor, the motor rotor of the flywheel electric motor starts to rotate. This will drive the flywheel to rotate as the clutch is closed. Thus, the electric energy is converted into rotational energy.

If the rotational energy of the flywheel is intended to be stored for a longer period of time, it is preferable to open the clutch. Thus, the flywheel can rotate freely with minimized energy loss. In order to convert the rotational energy back into electrical energy, the clutch must be closed again.

Finally, the flywheel is coupled to the flywheel generator such that the flywheel and flywheel generator are within a predetermined compliance ratio. This is preferably achieved by the clutch, in particular the same clutch which has been closed in the initial method step. By these means, the rotational energy of the flywheel is converted into electrical energy by the flywheel generator.

The method according to the invention has the same advantages as the foundation according to the first aspect of the invention and the wind turbine according to the second aspect of the invention. Thus, the inventive method for storing and using energy produced by a wind turbine has the following advantages: the electrical energy generated by the generator can be temporarily stored by the energy storage device and provided on demand, by means of cost-effective means and in a safe manner. With the present invention, it is possible to manage situations of smooth power output, improving black start, enhancing performance, and providing backup power, for example.

Preferably, in a further step, the electric motor is driven using the electrical energy generated by the flywheel generator to support rotation of the rotor of the wind turbine. The electric motor may be a generator of a wind turbine. This step is especially carried out in case the rotor of the wind turbine is not rotating and has to be accelerated to an operational rotational speed. This operation is also referred to as "black start". However, this step may be carried out to support the already rotating rotor, for example in the presence of gusts or intermittent winds, in order to prevent accidental stopping of the rotor. This has the following advantages: by common means and in a cost-effective manner, the efficiency of the wind turbine may be enhanced.

Drawings

Further advantages, features and details of the invention emerge from the following description, in which working examples of the invention are described in detail with reference to the drawings. Thus, the features from the claims, which are obtained individually or in any combination, as well as the features mentioned in the description, may be essential to the invention. In the drawings:

figure 1 shows a schematic side view of a prior art foundation of a wind turbine,

figure 2 shows a schematic cross-sectional side view of a preferred first embodiment of the invention,

Figure 3 shows a schematic perspective view of a first configuration of the invention,

figure 4 shows a schematic perspective view of a second configuration of the invention,

figure 5 shows a schematic side view of an electrical arrangement according to the invention,

figure 6 shows a schematic cross-sectional side view of a preferred second embodiment of the invention,

FIG. 7 shows a schematic side view of a preferred embodiment of a wind turbine according to the invention, and

fig. 8 shows a schematic flow chart of a preferred embodiment of the method according to the invention.

Elements having the same function and efficacy are each indicated in fig. 1 to 8 with the same reference numerals.

Detailed Description

In fig. 1, a prior art foundation 1 of a wind turbine 2 is shown in a schematic side view. The base 1 comprises a base means 3 with a central zone 4 and an outer zone 5. The tower 18 of the wind turbine 2 is mounted on the central area 4. Essentially, all of the load of the tower 18 is carried by the outer zone 5, with the inner zone 4 being a non-working load zone. The base means 3 of the foundation 1 is configured as a solid steel-concrete block with an inclined upper surface in the outer zone 5 and a horizontal upper surface in the central zone 4.

Fig. 2 shows a preferred first embodiment of the invention in a schematic sectional side view. In this figure, the central zone 4 of the base means 3 of the susceptor 1 is shown in detail, with the outer zone 5 being cut away for reasons of better overview. The foundation 1 of the wind turbine 2 comprises a base device 3, which base device 3 preferably comprises or consists of concrete, steel-concrete or the like. The energy storage means 7 of the base 1 are located in the central region 4 of the base 1. The energy storage device 7 is located inside a chamber 6, the chamber 6 being formed within the base device 3. The energy storage device 7 comprises a flywheel 8 having a vertical axis of rotation R. The flywheel 8 has a substantially cylindrical shape. The flywheel 8 is pivotally arranged in the chamber 6 by means of magnetic bearings 14 on the sides and bottom of the flywheel 8, thereby supporting the flywheel 8 against the inner wall of the chamber 6. The energy storage means 7 further comprises a transmission means 9 comprising a flywheel electric motor 10 with a motor rotor 19 and a clutch 13, the clutch 13 being configured as a magnetic clutch 13 for mechanically connecting and disconnecting the motor rotor 19 to and from the flywheel 8. The flywheel electric motor 10 is further configured as a flywheel generator 12. By means of the flywheel electric motor 10, the flywheel 8 can be rotated to convert electrical energy into rotational energy. The rotational energy of the flywheel 8 can be converted into electrical energy by means of the flywheel generator 12.

In fig. 3, a first configuration of the present invention is shown in a schematic perspective view. In this first configuration, the base 1 comprises only one single flywheel 8, which is pivotally arranged in the central zone 4. The flywheel 8 has a substantially cylindrical shape and has a size that almost completely fills the central region 4.

In fig. 4, a second configuration of the present invention is shown in a schematic perspective view. In this second configuration, the base 1 comprises nine flywheels 8, which are pivotally arranged in the central zone 4. The flywheels are evenly distributed over the central region 4, with one flywheel 8 located in the central axis of the central region 4 and the other eight flywheels 8 evenly distributed along a circle about the central axis. The flywheel 8 has a substantially cylindrical shape, wherein the diameter of the flywheel 8 according to the second configuration is much smaller than the diameter of the flywheel 8 according to the first configuration as shown in fig. 3.

Fig. 5 shows an electrical arrangement according to the invention in a schematic perspective view. The flywheel 8 is connected to a flywheel electric motor 10, wherein the flywheel electric motor 10 is configured as a flywheel generator 12. The clutch 13 is not shown in this figure, however, it is preferable that the clutch 13 is present between the flywheel 8 and the motor rotor 19. The rotor 15 with the rotor blades 16 is mechanically connected to a generator 17. The generator 17 is configured to convert rotational energy of the rotor 15 into electric energy. The generator 17 is further configured as an electric motor 20 for driving the rotor 15. The generator 17 is connected to the grid G and the flywheel motor 10 via electric wires and an electric control device 11. The electrical arrangement comprises several electrical switches 21 for switching between different operating configurations, such as driving the flywheel 8 by means of the flywheel motor 10, generating electrical power by means of the flywheel generator 12 for driving the electric motor 20 for driving the rotor 15 or providing electrical power to the grid G.

In fig. 6, a preferred second embodiment of the invention is shown in a schematic side view. In this figure, the central zone 4 of the base means 3 of the susceptor 1 is shown in detail, with the outer zone 5 being cut away for reasons of better overview. The foundation 1 of the wind turbine 2 comprises a base device 3, which base device 3 preferably comprises or consists of concrete, steel-concrete or the like. The energy storage means 7 of the base 1 are located in the central region 4 of the base 1. The energy storage device 7 is located inside a chamber 6, the chamber 6 being formed within the base device 3. The energy storage device 7 comprises a flywheel 8 having a horizontal axis of rotation R. The flywheel 8 has a substantially cylindrical shape. The flywheel 8 is pivotally arranged in the chamber 6 by means of magnetic bearings 14 on the sides of the flywheel 8, thereby supporting the flywheel 8 against the inner wall of the chamber 6. The energy storage means 7 further comprises transmission means 9 comprising a flywheel electric motor 10 with a motor rotor 19 and a clutch 13, the clutch 13 being configured as a magnetic clutch 13 for mechanically connecting and disconnecting the motor rotor 19 to the flywheel 8. The flywheel electric motor 10 is further configured as a flywheel generator 12. By means of the flywheel electric motor 10, the flywheel 8 can be rotated to convert electrical energy into rotational energy. The rotational energy of the flywheel 8 can be converted into electrical energy by means of the flywheel generator 12.

Fig. 7 shows a preferred embodiment of a wind turbine 2 according to the invention in a schematic side view. The wind turbine 2 comprises a base 1, a tower 18 and a rotor unit 22, the rotor unit 22 having a rotor 15, rotor blades 16 and a generator 17 also configured as an electric motor 20. A tower 18 is mounted to the foundation 1. A rotor unit 22 is mounted to the upper end of the tower 18.

In fig. 8, a preferred embodiment of the method according to the invention is shown in a schematic flow chart. In a first step 100, the clutch 13 is closed. Thereby, the flywheel 8 of the base 1 of the wind turbine 2 is mechanically coupled with the motor rotor 19 of the flywheel electric motor 10 of the base 1. In a second step 200, the electrical energy generated by the generator 17 of the wind turbine 2 is provided to the flywheel electric motor 10 by the electrical control means 11 of the base 1. In a third step 300, the flywheel electric motor 10 is operated with the supplied electric energy. By these means, the electric energy is converted into the rotational energy of the flywheel 8. In a fourth step 400, the clutch 13 is opened. Thus, the flywheel 8 is mechanically disengaged from the motor rotor 19 and can rotate freely. In this state, the flywheel 8 can rotate for several hours, thereby storing rotational energy. In a fifth step 500, the clutch 13 is closed again and the flywheel 8 is mechanically coupled again to the motor rotor 19. The fifth step 500 is preferably initiated when the wind speed is insufficient to drive the rotor 15 or unstable, the rotor 15 should be started and/or the grid G requires electrical energy. In a sixth step 600, the flywheel generator 12 generates electrical energy by converting the rotational energy of the flywheel 8. In a seventh step 700, the generated electrical energy is provided to the electric motor 20 for driving the rotor 15 and/or to the grid G for providing electrical energy to the grid. To provide electrical energy to the grid G, a converter is preferably used to condition the power generated by the flywheel so that it matches the grid demand.