Wind turbine and method for operating wind turbine

Abstract

Wind turbine comprising a rotor, a generator (6) driven by said rotor in order to generate energy, and an energy conversion device (7) comprising at least one energy conversion module (10), said energy conversion module (10): operable in an electrolyser mode in a first operating mode of said wind turbine (1), a generator (6) for generating hydrogen by electrolyzing water using energy provided by the generator (6); the energy conversion module (10) is operable in an electrolyser mode in a first operating mode of the wind turbine (1) and in a fuel cell mode in a second operating mode of the wind turbine (1) to generate energy by reacting hydrogen with oxygen wherein the energy conversion module (10) is switchable between the electrolyser mode and the fuel cell mode.

Description

Technical Field

[0001] The invention relates to a wind turbine comprising a rotor and a generator. Background Art

[0002] Wind turbines are generally used to generate electrical energy. A wind turbine comprises a number of rotor blades arranged at a hub, which is connected to a generator. The wind interacting with the turbine blades rotates the hub, thereby driving a generator, which generates electrical energy. Such wind turbines are arranged at sea or on land. The wind turbine is connected to an electricity network by means of a connecting cable for supplying the generated electrical power. Since the wind turbine is not always in operation, for example, due to an intermittent period or a reduction in production at a wind farm, the generator is not driven and therefore does not generate electrical power. However, many consumer systems of wind turbines require electrical power, such as control systems, rotor or blade rotation devices, safety equipment, lights, ventilation and cooling systems, and other electrical systems. This auxiliary power is generally provided by the power grid to which the wind turbine is connected.

[0003] Recently, a wind turbine that further includes an energy conversion device has been proposed, which is used to produce hydrogen by electrolyzing water using the electric power generated by the generator or the corresponding energy. In the second step, the electric power generated by converting wind energy is converted into hydrogen as an energy carrier medium by electrolyzing water (for example, seawater in the case of an offshore device). This is advantageous because it is not necessary to transport the electric power from the wind turbine to the power grid, so that it is not necessary to lay cables at the seabed, for example, in the case of an offshore device, or to lay cables on the ground in the case of an onshore device, because such cables are very expensive. Instead, a gas pipeline is required for transporting the produced hydrogen to the gas network, which is less cost-effective and easier to lay. In an alternative, in the case of an offshore device or even an onshore device, hydrogen can also be liquefied and transported by ship. However, in such a turbine embodiment, in which the electric power generated is converted again to produce hydrogen, power and gas production may also be interrupted due to intermittent periods or other restrictions. However, such a wind turbine also includes several power-consuming devices that require some auxiliary power. Since no cable connection is provided, the electrical power can be provided by a large battery installation arranged at the wind turbine. However, the batteries are heavy and expensive, especially because they need to be appropriately scaled to operate all power consuming systems of the wind turbine. Furthermore, such a battery system requires additional space, which is quite precious at the wind turbine, especially in offshore applications. Finally, the battery system is only an auxiliary system, which is used only on rare occasions, making the installation of such a battery system very questionable. Summary of the invention

[0004] It is an object of the present invention to provide an improved wind turbine.

[0005] To solve this object, the present invention proposes a wind turbine, which includes a wind turbine having a rotor, a generator driven by the rotor to generate energy, and an energy conversion device, the energy conversion device including at least one energy conversion module, which energy conversion module: can be operated in an electrolyzer mode in a first operating mode of the wind turbine to produce hydrogen by electrolyzing water using energy provided by the generator; and can be operated in a fuel cell mode in a second operating mode of the wind turbine to produce energy by reacting hydrogen with oxygen, wherein the energy conversion module can be switched between the electrolyzer mode and the fuel cell mode.

[0006] The invention proposes a wind turbine equipped with an energy conversion device comprising at least one energy conversion module operable in two different modes, namely: an electrolyser mode, in which the module produces hydrogen by using electrical energy provided by a generator, and a fuel cell mode, in which the module produces electrical energy from previously produced hydrogen and oxygen. The module is reversible, it can be switched between electrolyser mode and fuel cell mode, and vice versa, controlled by corresponding control means, which control the operating mode, for example based on information about the power generation of the generator, etc.

[0007] Since the energy conversion device or the corresponding energy conversion module can be operated in two different modes, it can generate electrical energy when the wind is blowing and no other restrictions that would affect the conventional wind turbine operating mode are given. If there are any restrictions, such as intermittent periods or wind farm curtailment or any other reason, which hinder the production of electrical energy, the energy conversion module can simply switch to the fuel cell mode. The module is now operable to generate the required electrical auxiliary energy from the previously produced hydrogen and the previously produced oxygen, both of which were previously produced by the electrolysis of water. In the alternative scheme of using the produced oxygen, oxygen in the ambient air can also be used, which avoids the storage of the produced oxygen. The electrical energy is now used to operate the corresponding consumption systems of the wind turbine, preferably in combination with one or more smaller buffer batteries or one or more supercapacitors, which provide initial starting current for the switching of modes and, for example, for the rotating equipment when the turbine is to be restarted. By installing such a reversible energy conversion device or a corresponding reversible energy conversion module, which can be operated in the electrolyzer mode or the fuel cell mode as required, the wind turbine is self-sufficient in terms of electrical power. When the wind turbine is operated in a conventional first operating mode, electric power is produced by the generator, which power is of course also used to operate all consumer systems of the wind turbine. And when the wind turbine is operated in a second operating mode, in which the generator does not produce electric power, the energy conversion module provides the necessary auxiliary power for operating all systems of the wind turbine without any external electric energy or without the need to install a large-scale battery buffer system. In the case that the wind turbine starts operating but the generator has not yet covered the entire load of the auxiliary systems, then both systems can provide electric energy, so that both systems, namely the generator and the conversion device or the corresponding switchable conversion module, contribute to the production of electricity.

[0008] The wind turbine of the invention thus not only avoids the use of expensive cables because it produces hydrogen as an energy carrier, but is also a self-sufficient device because the required auxiliary electric power is generated simply by reversing the operating mode of the energy conversion module. This power production is based on previously produced hydrogen and oxygen present in the air or also produced during an electrolysis process in which water is decomposed into hydrogen and oxygen.

[0009] The central feature of the present invention is a switchable energy conversion device or a corresponding conversion module, which is reversible in its operating mode. Various module types that utilize a specific electrolysis method to work can be used. The module can be, for example, a proton exchange membrane water electrolyzer (PEMWE) and an alkaline water electrolyzer (AWE), an anion exchange membrane water electrolyzer (AEMWE), a solid oxide electrolyzer (SOEC) or a proton conducting ceramic electrolyzer (PCCEL). This enumeration is not restrictive. All these types of specific electrolyzer devices or modules can be used as reversible modules, which can be switched in the manner of the present invention to produce hydrogen or electric power. The stack can only include modules of the same type, but can also include modules of different types.

[0010] As mentioned, auxiliary electric power is only needed in rare cases. Therefore, the energy conversion module is also rarely operated in the fuel cell mode. Therefore, according to another embodiment of the present invention, it is advantageous when the energy conversion device includes one or more energy conversion modules that can only be operated in the electrolyzer mode and at least one energy conversion module that can be operated in both modes. The amount of energy required in the idle mode of the wind turbine, that is, the second operating mode, is much lower than the hydrogen that the system can produce in the conventional first operating mode. Therefore, using two energy conversion modules that can only be operated in the electrolyzer mode and are reversible in a corresponding number, the size of the energy conversion device is adjusted so that it produces at a very high hydrogen production rate. A relatively small amount of auxiliary electric energy is provided by at least one specific energy conversion module that can be operated in both modes. Therefore, when the wind turbine is operated in the first operating mode of generating electric energy, all energy conversion modules are operated in the production mode and produce hydrogen. But in the case of an intermittent period or other restrictions, when no electric energy is generated, only the at least one energy conversion module that can also be operated in the fuel cell mode works, because the module generates enough auxiliary energy for all consumption systems that operate the wind turbine in this case. For example, the module stack may include ten energy conversion modules. Nine of these modules are operable only in electrolyser mode and are of the same module type, but only one module is a reversible module, which may be of the same type as the nine modules, or of another type. This is of course only an example and such scaling may of course be different depending on the amount of electrical power produced by the generator that needs to be converted into hydrogen and the amount of auxiliary electrical power required.

[0011] As mentioned, the energy conversion module reconverts the previously produced hydrogen into electrical energy, preferably also using previously produced oxygen or using oxygen present in the air. There are various options for the source of hydrogen for this reconversion. According to a first embodiment, a hydrogen reservoir is provided for storing at least a certain amount of hydrogen produced in electrolyzer mode, from which the hydrogen is supplied to the energy conversion module when operating in fuel cell mode. The turbine is provided with a specific hydrogen reservoir in which some hydrogen is buffered, which is used only in the case where auxiliary electrical power is required. The hydrogen can be supplied to the energy conversion module from the reservoir by means of a pump, but preferably, the hydrogen is stored in the hydrogen reservoir at a suitable pressure of at least 20 bar or preferably higher, so that gaseous hydrogen is supplied to the module due to the high pressure, so that no pump is required.

[0012] The hydrogen storage itself is preferably arranged at the wind turbine. Such a storage in which pressurized hydrogen is stored can be easily arranged, for example, in the wind turbine tower or at another suitable location and can be simply connected to the energy conversion module by means of a gas pipe. The storage itself is a simple gas storage, which is suitable for storing pressurized hydrogen. This storage device is particularly advantageous when, for example, hydrogen is transported from the turbine to the coast by ship, etc. Of course, however, such a hydrogen storage can also be arranged at the turbine when a hydrogen pipeline is provided.

[0013] If such a hydrogen storage is provided at the turbine, a subsequent processing device can also be provided for processing the produced hydrogen into another gaseous product. According to this embodiment, the wind turbine is a power-X device, which means that the produced electrical power is not only converted into hydrogen, but the hydrogen can also be converted into another product, such as methane, methanol, ammonia (liquid or gaseous) or even fuel for combustion engines, etc. In this case, the hydrogen storage is useful for buffering the specific amount required to generate auxiliary electrical energy when the hydrogen is subsequently processed into another product.

[0014] In another embodiment of the invention, as an alternative to arranging a hydrogen storage at the wind turbine, the energy conversion module can also be adapted to operate in fuel cell mode using hydrogen produced in electrolyzer mode from a hydrogen pipeline coupled to the wind turbine. If the wind turbine is coupled to a hydrogen pipeline, the produced hydrogen is pumped into the pipeline at high pressure, which is typically a pressure of about 20-80 bar. Therefore, there is highly pressurized hydrogen in the pipeline. If the wind turbine is now in a situation where the generator does not produce electrical power but requires auxiliary electrical power, the module is switched to fuel cell mode, where hydrogen can simply be received from the pipeline. Due to the high gas pressure in the pipeline, hydrogen automatically supplies energy to the energy conversion module, which can now reconvert the hydrogen by reacting hydrogen with oxygen to produce electrical power. In this embodiment, no specific pump or the like is required to provide hydrogen to the module, as in the embodiment with a hydrogen storage, where the hydrogen is also buffered in a pressurized state.

[0015] As mentioned previously, a wind turbine can not only produce hydrogen, but also act as a power-to-X-turbine having a subsequent processing device for producing another product based on the produced hydrogen. The wind turbine device previously described may include a hydrogen storage device from which hydrogen is obtained in order to generate auxiliary electrical power when needed. According to an alternative, the wind turbine device of the present invention may also include a subsequent processing device for processing the produced hydrogen into another product. This embodiment further includes a conversion device for changing the product back into hydrogen, which causes the energy conversion module to operate in a fuel cell mode. In this embodiment, the wind turbine is equipped with a conversion device for changing products such as ammonia, methanol, methane, etc. back into hydrogen, which is then converted back into electrical power by the energy conversion module. In this case, no specific hydrogen storage device is required.

[0016] The products produced by the subsequent processing device can be stored in a product storage device at least to a certain amount, and the products are supplied from the product storage device to the conversion device to produce hydrogen for operating the energy conversion module in fuel cell mode. According to this embodiment, an additional product storage device is provided at the turbine. In an alternative, the conversion device can also be suitable for using production products from a product gas or liquid pipeline coupled to the wind turbine to produce hydrogen. Just like in the previously described embodiment, in which hydrogen is used from a hydrogen pipeline to operate the energy conversion module, in this embodiment, the product is also obtained from a product gas or liquid pipeline coupled to the wind turbine for operating the conversion device. In addition, the product gas here is present in the gas pipeline at high pressure, and the high pressure is also, for example, a pressure of 20-80 bar, and the product liquid is pumped back to the conversion device from the liquid pipeline.

[0017] The wind turbine installation itself can be an offshore installation. The turbine is installed at the sea and can, for example, but preferably, be coupled to the coast via a gas pipeline, wherein, depending on the arrangement of the wind turbine installation, hydrogen or other gaseous or liquid products are supplied. However, an onshore installation is also feasible. In this embodiment, the wind turbine is arranged on the ground and is preferably connected to a pipeline. In this onshore embodiment, the water used in the electrolyser installation can be drinking water or, when the wind turbine is close to the sea, seawater.

[0018] A buffer system may also be provided, which includes some small batteries or supercapacitors, to provide backup power, especially for switching the switchable module. The buffer system provides initial power for switching the mode of the reversible module.

[0019] The invention also relates to a method for operating a wind turbine having a rotor, a generator driven by the rotor to generate energy, and an energy conversion device comprising an energy conversion module, which in a first operating mode of the wind turbine is operated in an electrolyzer mode, thereby generating hydrogen by electrolyzing water using energy provided by the generator, and in a second operating mode of the wind turbine, when the generator does not generate energy or generates insufficient energy, switches to a fuel cell mode, thereby generating energy by reacting hydrogen with oxygen.

[0020] The hydrogen used in the fuel cell operating mode may be provided by a hydrogen storage in which at least a certain amount of hydrogen produced in the electrolyser mode is stored. In an alternative embodiment, the hydrogen may also be supplied by a hydrogen line coupled to the wind turbine.

[0021] According to another embodiment, a subsequent processing device for processing the produced hydrogen into another gaseous or liquid product and a conversion device for converting the product back into hydrogen are provided, wherein the hydrogen is produced by the conversion device for operating the energy conversion module in fuel cell mode. In this embodiment, a double energy conversion from electrical energy to hydrogen and then to the product, and vice versa, is performed for generating auxiliary electrical power.

[0022] At least a certain amount of the product produced by the subsequent processing device can be stored in a product storage, from which the product is supplied to the conversion device to produce hydrogen for operating the energy conversion module in fuel cell mode. In an alternative to such a product storage or a corresponding product tank, the product can also be provided to the conversion device via a product gas or liquid pipeline coupled to the wind turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. However, the accompanying drawings are only schematic diagrams designed for illustrative purposes only and do not limit the present invention. The accompanying drawings show:

[0024] Figure 1 is a schematic diagram of a wind turbine according to a first embodiment of the present invention,

[0025] Figure 2 is a schematic diagram of a wind turbine of the present invention including a second embodiment of a hydrogen storage,

[0026] Figure 3 is a schematic diagram of a wind turbine of the present invention according to a third embodiment, which includes a subsequent processing device and a conversion device, and

[0027] Figure 4 is a schematic diagram of a wind turbine according to the invention comprising a fourth embodiment of an additional product storage. DETAILED DESCRIPTION

[0028] Figure 1 A wind turbine 1 of the invention is shown, comprising a tower 2, on top of which a nacelle 3 is arranged. The nacelle 3 comprises a hub 4, to which a number of rotor blades 5 are attached. When the wind interacts with the blades 5, the hub 4 will rotate. The hub 4 is coupled directly or via a gearbox to a generator 6, which when driven by the rotating hub 4 generates electrical energy.

[0029] The generator 6 is coupled to an energy conversion device 7 designed to produce hydrogen by electrolysis of water, in this embodiment, since the wind turbine 1 is an offshore facility, the water is seawater 8 pumped to the energy conversion device 7. The seawater may be processed by a purification system before it is supplied to the energy conversion device. The energy conversion device is coupled to a generator 6, which provides the electrical power required for electrolysis of water.

[0030] The energy conversion device 7 comprises several energy conversion modules 9 which are only capable of electrolyzing water, so they can only be operated in electrolyzer mode.

[0031] In this example, the energy conversion device 7 also includes an energy conversion module 10, which is a conversion module that can be operated in two different modes. It operates in an electrolyzer mode, in which it is able to electrolyze water 8, just like the energy conversion module 9. But the energy conversion module 10 can also operate in a second fuel cell mode, in which it works as a fuel cell with a reverse operation process. In this fuel cell mode, the energy conversion module 10 generates electrical energy by using previously produced hydrogen, which is produced by all modules 9, 10, which reacts with oxygen for the production of electrical power, as is known from the working principle of fuel cells. Oxygen is also previously produced, or air is used to provide oxygen. If necessary, the mode of the energy conversion module 10 can be reversed by switching, so that whenever additional electrical power is needed, it can be supplied only by operating the energy conversion module 10 in the fuel cell mode. This auxiliary electrical power may be needed when the conditions have changed so that the hub cannot rotate due to intermittent periods or, for example, due to restrictions caused by a multi-turbine park in which the wind turbine 1 of the present invention is integrated. In this case, although the generator 6 does not generate electrical power, a large number of electrical appliances of the wind turbine 1, such as control systems, rotor or blade rotation devices, lights, safety equipment, ventilation and cooling systems and other electrical equipment, still need to work. In this case, the energy conversion module 10 is switched to the fuel cell mode so that auxiliary electrical power is provided during this period of time until the wind turbine 1 returns to the first operating mode, that is, the normal mode in which the hub 4 rotates and the generator 6 generates electrical power.

[0032] The energy conversion device 7 or all modules 9, 10 respectively are connected to a hydrogen pipeline 11 which extends to the coast for delivering the produced hydrogen to the pipeline network on the coast. When switched to fuel cell mode, the energy conversion module 10 obtains a supply of hydrogen from this pipeline 11. The hydrogen in the pipeline 10 is pressurized at a gas pressure of about 20-80 bar, so that a return flow for supplying hydrogen to the module 10 is easily achieved.

[0033] A control device 17 is shown, which controls the operation of the corresponding items. It receives information about power generation from the generator and auxiliary systems, and controls the energy conversion device or the corresponding reversible module accordingly, so that the operating mode is switched when necessary.

[0034] Of course, although not explained in detail, in order to control the corresponding airflow, etc., corresponding valves and control devices, etc. are provided.

[0035] The energy conversion device 7 is designed to produce a high hydrogen output, so that a certain number of first modules 9 that only produce hydrogen are provided. It is sufficient to provide only one or several "dual-function" modules 10 that can be switched between electrolyzer mode and fuel cell mode, because during intermittent periods or other interruptions in the production of the generator, the amount of electrical power required to operate and maintain all necessary systems is significantly lower than the electrical energy generated by the generator when it is running in the normal operating mode. Therefore, it is sufficient to provide only a small-capacity fuel cell mode, which is just enough to produce sufficient auxiliary electrical power. During the operation of the modules 10, all modules 9 are of course inactive, because they do not receive an electrical power supply from the generator 6. However, it is of course also possible to have only modules of the reversible type in a stack so that the entire module stack can be switched between the two modes if necessary.

[0036] Figure 2 A second embodiment of a wind turbine 1 according to the invention is shown. The same reference numerals apply to the same items. The turbine 1 further comprises a tower 2 and a nacelle 3 with a hub 4 and rotor blades 5. The nacelle 3 comprises a generator 6 and an energy conversion device 7, which are connected to the tower 2 and the nacelle 3. Figure 1 The generator and energy conversion device are similar. The energy conversion device 7 also includes a number of energy conversion modules 9 that only produce hydrogen and can only operate in electrolyzer mode. The device 7 also includes an energy conversion module 10 that can operate in electrolyzer mode and fuel cell mode and can switch between these modes.

[0037] In this embodiment, too, all modules 9, 10 are coupled to a hydrogen pipeline 11, to which the produced hydrogen is supplied in order to be delivered to the hydrogen network. Figure 1 Unlike the embodiment of FIG. 1 , when the dual-function energy conversion module 10 is operated in the fuel cell mode when auxiliary power is required, the energy conversion module 10 is not supplied with hydrogen from the pipeline 11. Figure 2 In an embodiment, an additional hydrogen storage tank 12 is provided, which is supplied with hydrogen until it reaches a certain filling level. The hydrogen is preferably stored in the storage tank 12 under pressure, which pressure is also preferably a pressure between 20-80 bar. A small compressor can be coupled to the storage tank in combination with a pressure regulating valve in the return direction. If necessary, the module 10 is supplied with hydrogen from the hydrogen storage tank 12, wherein, due to the pressurized storage of hydrogen, no additional pump is required here either. Likewise, a certain number of valves and control devices etc. are provided to control the corresponding gas flows and operations.

[0038] Working principle and target Figure 1When the hub 4 is not rotating and the generator 6 is not driven, no electrical power is produced and all modules 9 are inactive. Only module 10 is active and switches to fuel cell mode, in which it converts previously produced hydrogen from the reservoir 12, by reacting it with oxygen, also previously produced due to the electrolysis of water (and ultimately stored in a separate oxygen reservoir), or present in the air, to produce electrical energy.

[0039] Figure 3 An embodiment of a wind turbine 1 of the invention is shown, which has a tower 2, a nacelle 3, a hub 4, blades 5 and a generator 6, to which an energy conversion device 7 is coupled, the energy conversion device 7 comprising several single-function electrolytic energy conversion modules 9 and a dual-function energy conversion module 10. The wind turbine 1 is a power-X turbine, in which not only hydrogen is produced by the energy conversion device 7, but also another end product is produced by using the produced hydrogen. In this embodiment, a subsequent processing device 13 is provided, which produces another product by using the hydrogen produced in the energy conversion device 7. For example, such a product may be ammonia, methanol, methane or a fuel, for example for running a combustion engine or the like. The processing device 13 is of course suitable for carrying out the corresponding chemical reaction and is provided with corresponding additional substances or the like for carrying out the corresponding chemical reaction, depending on what type of product is to be produced.

[0040] The subsequent processing device 13 is coupled to a product pipeline 14 which, like the hydrogen pipeline 11 , extends to the coast for distributing the produced gaseous or liquid products to a subsequent product pipeline network.

[0041] In order to allow the energy conversion module 10 to generate auxiliary electrical energy, which is also based on reversing it to fuel cell mode, it is necessary to supply hydrogen to the module 10, which hydrogen can react with oxygen. But the hydrogen has already been converted into this product by the processing device 13. Therefore, a conversion device 15 is provided to which, when necessary, the product previously produced in the processing device 13, such as ammonia or the like, is supplied. The conversion device, i.e. a reformer or the like, converts this product back into hydrogen and whatever other gas, depending on the product. This hydrogen is then supplied to the module 10, which is connected to the conversion device 15, such as Figure 3 Likewise, corresponding valves, control devices and other necessary items are of course provided to control the corresponding gas flow and process.

[0042] at last, Figure 4A fourth embodiment of a wind turbine 1 of the invention is shown, comprising a tower 2, a nacelle 3, a hub 4 and blades 5. The hub 4 is coupled to a generator 6, which is coupled to an energy conversion device 7, which is supplied with electrical energy by the generator 6. The device 7 comprises several energy conversion modules 9, which convert electrical power only into hydrogen, which operate only as electrolyzers. The device 7 also comprises an energy conversion device 10, which can also be operated in fuel cell mode, as has been described previously.

[0043] Likewise, a subsequent processing device 13 is coupled to the energy conversion device 10 , which processes the hydrogen produced by the device 7 into another product, for example for producing ammonia or methane or methanol, etc., by using other reaction substances, and then the product is supplied to the product pipeline 14 .

[0044] Although in Figure 3 In the embodiment of the present invention, the conversion device 15 is supplied with the product to be converted back into hydrogen by the product line 14, but in Figure 4 In the embodiment of the invention, an additional product reservoir 16 is provided, which is supplied with gaseous or liquid products stored in a pressurized state by the processing device 13. If necessary, the products are supplied from the reservoir 16 to the conversion device 15, which converts the products back to produce hydrogen, which is then fed again to the energy conversion module 10, where it is converted into electrical energy when the module 10 is operated in fuel cell mode.

[0045] This embodiment shows only a certain number of modules 9 and one module 10. Of course, the module stack can also be scaled differently. For example, the stack can include ten or fifteen modules 9 that only produce hydrogen, which can only operate in electrolyzer mode. In addition, one or perhaps two modules 10 are provided, which can be switched between electrolyzer mode and fuel cell mode, and this small number is necessary and sufficient for providing auxiliary electrical power. In an alternative, all modules can also be of reversible type, so that the stack only includes these switchable modules and can be switched as a whole in its operating mode.

[0046] The corresponding devices, such as the energy conversion device 7, the subsequent processing device 13, the transformation device 15 or the corresponding storage 12, 16, are all shown to be integrated in the nacelle 3. This is possible if there is enough space. If not, it is of course also possible to arrange one or more of these items elsewhere, such as on a platform outside the nacelle 3, or even in the hollow tower 2 or its foundation, in which, for example, a storage device can be integrated, which storage device is nothing more than a relatively simple storage device or tank for gas or liquid.

[0047] The accompanying drawings are simple schematic diagrams showing relevant items in possible devices or corresponding embodiments. Of course, the arrangement of items may also differ from that shown in the drawings. For example, due to weight, maintenance and space limitations, storage, energy conversion devices, subsequent processing devices and / or conversion devices may not be placed in the nacelle, but at a platform outside the nacelle or around, at or in the tower (e.g., at the ground, at a certain platform level or even in the foundation).

[0048] Finally, although the figures show an offshore wind turbine installation, the present invention also relates to onshore wind turbine installations.

[0049] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the disclosed examples, from which a skilled person will be able to derive other variations without departing from the scope of the present invention.

Claims

1. A wind turbine comprising a rotor, a generator (6) driven by the rotor to generate energy, and an energy conversion device (7), the energy conversion device (7) comprising at least one energy conversion module (10), the energy conversion module (10) being operable in an electrolyser mode in a first operating mode of the wind turbine (1) to generate hydrogen by electrolyzing water using energy provided by the generator (6); and in a fuel cell mode in a second operating mode of the wind turbine (1) to generate energy by reacting hydrogen with oxygen, wherein: The energy conversion module (10) is switchable between the electrolyzer mode and the fuel cell mode.

2. The wind turbine according to claim 1, characterized in that The energy conversion device (7) comprises one or more energy conversion modules (9) capable of operating only in the electrolyser mode and at least one energy conversion module (10) capable of operating in both modes.

3. The wind turbine according to claim 1 or 2, characterized in that A hydrogen storage (12) is provided for storing at least a certain amount of hydrogen generated in the electrolyser mode, and when operating in the fuel cell mode, the hydrogen is supplied from the storage (12) to the energy conversion module (10).

4. The wind turbine according to claim 3, characterized in that The hydrogen storage (12) is arranged at the wind turbine (1).

5. The wind turbine according to claim 4, characterized in that A subsequent processing device (13) is provided for processing the produced hydrogen into another product.

6. The wind turbine according to claim 1 or 2, characterized in that: The energy conversion module (10) is adapted to operate in the fuel cell mode using hydrogen produced in the electrolyser mode from a hydrogen line (11) coupled to the wind turbine (1).

7. The wind turbine according to claim 1 or 2, characterized in that: Subsequent processing means (13) are provided for processing the produced hydrogen into another product and conversion means (15) are provided for converting the product back into hydrogen which enables the energy conversion module (10) to operate in the fuel cell mode.

8. The wind turbine according to claim 7, characterized in that A product storage (16) is provided for storing at least a certain amount of the product produced by the subsequent processing device (13), and the product is supplied from the storage (16) to the conversion device (15) to produce hydrogen for operating the energy conversion module (10) in the fuel cell mode, or the conversion device (15) is suitable for using production products from a product gas or liquid pipeline (14) coupled to the wind turbine to produce hydrogen.

9. A wind turbine according to any one of the preceding claims, characterised in that A control device (17) is provided for controlling the operation of the energy conversion device (7), in particular the switchable module (10).

10. A wind turbine according to any one of the preceding claims, characterised in that A buffer system is provided for providing a backup power supply, in particular for switching a switchable module (10).

11. A wind turbine according to any one of the preceding claims, characterised in that The wind turbine is an offshore installation or an onshore installation.

12. A method for operating a wind turbine, the wind turbine having a rotor, a generator (6) driven by the rotor to generate energy, and an energy conversion device (7) comprising an energy conversion module (10), the energy conversion module (10) being operated in an electrolyser mode in a first operating mode of the wind turbine (1) to generate hydrogen by electrolyzing water using energy provided by the generator (6), and in a second operating mode of the wind turbine (1), when the generator (6) generates no energy or generates insufficient energy, switching to a fuel cell mode to generate energy by reacting hydrogen with oxygen.

13. The method according to claim 12, characterized in that The hydrogen used in the fuel cell operating mode is provided by a hydrogen storage (12) in which at least a certain amount of hydrogen produced in the electrolyser mode is stored, or the hydrogen is supplied by a hydrogen line (11) coupled to the wind turbine (1).

14. The method according to claim 12, characterized in that A subsequent processing device (13) for processing the generated hydrogen into another product and a conversion device (15) for converting the product back into hydrogen are provided, wherein the hydrogen generated by the conversion device (15) is used to operate the energy conversion module (10) in the fuel cell mode.

15. The method according to claim 13, characterized in that At least a certain amount of the product produced by the subsequent processing device (13) is stored in a product storage device (16), and the product is supplied from the product storage device (16) to the conversion device (15) to produce hydrogen for operating the energy conversion module (10) in the fuel cell mode, or the product is provided to the conversion device (15) via a product gas pipeline (14) coupled to the wind turbine (1).

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