Apparatus, systems and methods for generating and storing hydrogen gas

Abstract

An apparatus, a system and a method for generating and storing hydrogen gas are disclosed. In one arrangement, an apparatus comprises a wind turbine, a solar array comprising at least one solar panel, an electrolyser unit having an electrolyser peak capacity and powered by the wind turbine and / or the solar array, and a pipeline configured to receive and store hydrogen from the electrolyser unit and having a length at least equal to 500 meters per 10MW of the electrolyser peak capacity. In another arrangement a method comprises generating energy at the wind turbine and the solar array comprising at least one solar panel, receiving the generated energy at the electrolyser unit, generating hydrogen gas with the generated energy by the electrolyser unit, and receiving and storing the generated hydrogen gas in a pipeline.

Description

APPARATUS, SYSTEMS AND METHODS FOR GENERATING AND STORING HYDROGEN GASTECHNICAL FIELD

[0001] The present invention relates to apparatus, systems and methods for generating and storing hydrogen gas. In particular, hydrogen gas is generated by an electrolyser unit that is powered by wind and solar energy, and the hydrogen gas is stored in a pipeline.BACKGROUND

[0002] With the increasing need to reduce the planet’s carbon footprint, the demand for alternatives to fossil fuels, such as hydrogen gas, has increased substantially. Known methods of generating hydrogen include separating water (H2O) into its separate components, namely hydrogen (H2) and Oxygen (O2), with an electrolyser powered by an energy source. Current large- scale hydrogen production relies on the electrolyser being powered with energy supplied by an electrical power grid. In most countries, a significant fraction of energy supplied by the grid is generated using fossil fuels. Thus, any hydrogen gas produced using energy from the grid leaves a significant carbon footprint due to the emission of greenhouse gases from the burning of fossil fuels.

[0003] To address this problem, hydrogen gas can be generated with energy generated by renewable and carbon-neutral sources such as from a wind turbine and / or an array of solar panels (a solar array). However, this raises a number of additional problems. For instance, areas in which wind turbines and / or solar arrays could be set-up might not be connected to a power grid. Connecting wind turbines and / or solar arrays in remote areas to the power grid (so that the energy can then be used to generate hydrogen with an electrolyser) requires significant investment. Furthermore, transporting energy (in the form of electricity) generated by wind turbine(s) and / or solar array(s) through a power grid is inefficient due to the losses in voltage and AC / DC conversion necessary for long distance transmission lines.

[0004] There is also an increasing demand for efficient hydrogen storage and transportation. Hydrogen can be stored in pressurised form as a gas or a liquid in tanks. Those tanks can be transportable (for example by being mounted on a vehicle) to transport the hydrogen gas from the production site (i.e. at the electrolyser) to where it is needed. However, storing hydrogen in tanks is not feasible with large scale hydrogen production because large hydrogen tanks are technically complicated and expensive to manufacture. Furthermore, storing hydrogen gas in large tanks brings a number of other inefficiencies. For example, when the tank is full, the electrolyser cannot be used anymore to produce hydrogen gas. Furthermore, transporting the hydrogen gas is expensive because it requires filling moveable tanks (i.e. those mounted on vehicles) and transporting the hydrogen on those vehicles. Furthermore, liquifying hydrogen is energy intensive, requiring up to 25% of the energy required to produce the hydrogen. Further still, a firm (i.e.reliable) supply of hydrogen cannot be guaranteed where the hydrogen is needed because the supply of hydrogen is dependent on a tank being full or empty.SUMMARY

[0005] An aim of the invention is to provide an efficient means of producing hydrogen at remote locations and for dynamic storage of hydrogen gas. In particular, the invention aims to provide for dynamic storage of hydrogen generated off-grid and enable a firm supply of hydrogen gas.

[0006] According to an aspect of the invention, there is provided an apparatus for generating and storing hydrogen gas. The apparatus comprises a wind turbine, a solar array comprising at least one solar panel, an electrolyser unit having an electrolyser peak capacity and powered by the wind turbine and / or the solar array, and a pipeline configured to receive and store hydrogen from the electrolyser unit and having a length at least equal to 500 metres per 10MW of the electrolyser peak capacity.

[0007] According to another aspect of the invention, there is provided an apparatus for generating and storing hydrogen gas. The apparatus comprises a wind turbine, a solar array comprising at least one solar panel, an electrolyser unit comprising one or more electrolysers, the electrolyser unit having an electrolyser peak capacity and powered by the wind turbine and / or the solar array, and a pipeline configured to receive and store hydrogen from the electrolyser unit and having a length at least equal to 500 metres per 10MW of the electrolyser peak capacity, wherein the wind turbine, the solar array and the electrolyser unit are electrically coupled to a common direct current (DC) bus of an electric power distribution system.

[0008] According to another aspect of the invention, there is provided a system for generating and storing hydrogen gas comprising the two of the apparatuses provided above, wherein the pipeline is shared by the electrolyser units of the apparatuses. Optionally, the system further comprises a third apparatus as provided above, wherein the pipeline of the third apparatus is not shared with the pipeline of the first and second apparatuses.

[0009] According to yet a further aspect of the invention, there is provided a method of generating and storing hydrogen gas. The method comprises generating, at a wind turbine and a solar array comprising at least one solar panel, energy and receiving, at an electrolyser unit, the generated energy. The method further comprises generating, by the electrolyser unit, hydrogen gas with the generated energy; and receiving and storing the generated hydrogen gas in a pipeline. In the method, the electrolyser unit has an electrolyser peak capacity, and the pipeline has a length at least equal to 500 metres per 10 MW of the electrolyser peak capacity.

[0010] According to yet a further aspect of the invention, there is provided a method of generating and storing hydrogen gas. The method comprises generating, at a wind turbine and a solar array comprising at least one solar panel, energy and receiving, at an electrolyser unit comprising one or more electrolysers, the generated energy. The method further comprisesgenerating, by the electrolyser unit, hydrogen gas with the generated energy; and receiving and storing the generated hydrogen gas in a pipeline. In the method, the electrolyser unit has an electrolyser peak capacity, the pipeline has a length at least equal to 500 metres per 10 MW of the electrolyser peak capacity, and the wind turbine, the solar array and the electrolyser unit are electrically coupled to a common direct current (DC) bus of an electric power distribution system.FIGURES

[0011] The invention will be more clearly understood from the following description of exemplary embodiments and the accompanying drawings, in which:Figures 1A to II are schematic diagrams of modular units for generating and storing hydrogen;Figure 2 is a schematic diagram of an example of a plurality of modular units coupled to a pipeline;Figure 3 is a schematic diagram of an example of a plurality of modular units coupled to a service hub and a pipeline system;Figure 4 is a schematic diagram of an alternative example of a plurality of modular units coupled to a service hub and a pipeline system;Figure 5 is a schematic diagram of an example of a large-scale system for generating and storing hydrogen gas;Figure 6 is a schematic diagram of an alternative example of a large-scale system for generating and storing hydrogen gas;Figure 7 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas;Figure 8 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas;Figure 9 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas;Figure 10 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas;Figure 11 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas;Figure 12 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas;Figure 13 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas; andFigure 14 is a schematic diagram of a further alternative example of a large-scale system for generating and storing hydrogen gas.

[0012] In the various drawings, like parts are denoted by like references.DESCRIPTION

[0013] Hydrogen gas is a potential replacement for fossil fuels in various industrial processes but only if it can be manufactured economically and with a low environmental impact. Manufacturing hydrogen using power from a conventional power grid is generally not economic and may have an undesirably high carbon footprint if the power sourced from the grid has a high proportion of power obtained from fossil fuels. Therefore, it is desirable to manufacture hydrogen, e.g. through electrolysis, using green power sources (e.g. wind or solar) directly. However, locations that are suitable for large wind and solar power installations, e.g. having reliable levels of sunlight and wind as well as not having a detrimental environmental impact, are often located in remote locations that may not be close to the intended user of the hydrogen. Also, wind and solar are intermittent, even at the most reliable locations, and therefore providing a continuous supply of hydrogen (often referred to as firm hydrogen) using such sources may be difficult.

[0014] The present invention proposes to address both of these problems by generating hydrogen using power derived from one or more wind turbines and one or more solar arrays co-located with one or more electrolysers and using a pipeline that has sufficient capacity to even out variations in the hydrogen generation caused by intermittent or variable power generation by the wind and solar power sources to connect the hydrogen generator to a user of the hydrogen. In addition, the present invention can benefit from improved efficiency in utilisation of green power by avoiding losses in transforming electrical power and transporting it through a grid. Local power storage can be provided to smooth out variation in the power generation and to maintain equipment in a stand-by condition when there is no solar or wind generation.

[0015] Figures 1A to II depict hydrogen generator modules 100 for generating and storing hydrogen gas. The hydrogen generator module 100 may be one of a plurality of modules 100 that, together, are coupled to one or more pipelines 110 as is described in more detail below with reference to systems for generating hydrogen depicted in Figures 2 to 14. Any of the hydrogen generator modules of Figures 1 A to II may function as the generator modules of the systems of Figures 2 to 14. Different types of hydrogen generator modules may be combined in a system. The hydrogen generator module 100 comprises a wind turbine 102, a solar array 104 comprising at least one solar panel, an electrolyser unit 106 and a pipeline 110. The electrolyser unit 106 is colocated with the wind turbine 102 and the solar array 104. The electrolyser unit 106, wind turbine 102 and solar array 104 are desirably within an area of less than 10 hectare (ha), optionally less than 1 ha, further optionally less than 0.5 ha.Co-location of the electrolyser unit 106, wind turbine 102 and solar array 104 means that the (electrical) energy generated by the wind turbine 102 and / or the solar array 104 can be fed directly to the electrolyser and that hydrogen gas is produced directly at the source of the electrical energy.Advantageously, this arrangement bypasses the need to transport electricity from the point at which it is generated (for example by a wind turbine and / or a solar array in a field) over long distances to electrolysers. Accordingly, inefficiencies and energy losses that occur due to the transport of electricity (for example, transforming generated electricity to a high voltage, heat losses during the transport, and transforming the high voltage current back to a low current) can be mitigated or eliminated by placing the electrolyser unit close to the wind turbine 102 and the solar array 104. For example losses that can be avoided may include: about 8% for converting wind or solar DC power to AC; about 3% for low to high voltage conversion; about 3% for long distance transmission; about 3% for high to low voltage conversion and about 5% for DC rectification.

[0016] The wind turbine, the solar array and the electrolyser unit of the hydrogen generator module 100 may be electrically coupled to a common direct current (DC) bus of an electric power distribution system. The electric power distribution system will be described in more detail later.

[0017] The electrolyser unit 106 has a peak capacity and is powered by the wind turbine 102 and / or the solar array 104. The peak capacity of the electrolyser unit 106 is the maximum power that the electrolyser unit 106 can process to generated hydrogen gas. The electrolyser unit 106 is a large industrial sized electrolyser unit. For example, the peak capacity can be from 3 to 50 Megawatt (MW). The electrolyser unit 106 comprises at least one electrolyser 108. In some arrangements, the electrolyser unit 106 comprises a plurality of electrolysers 108 arranged in parallel. For example, the electrolyser unit 106 could comprise five electrolysers 108 as depicted in Figure 1A. However, the number of electrolysers arranged in parallel is not limited to one or five and can be any number of electrolysers arranged in parallel. Placing the electrolysers 108 in parallel reduces the need for a high voltage requirement which in turn reduces the need for large voltage transformations that can lead to loss in energy (efficiency).

[0018] Alternatively or additionally, the electrolyser unit 106 may comprise a plurality of electrolysers 108 arranged in series. For example, the electrolyser unit 106 may comprise a string of two or more electrolysers 108 arranged in series, with two or more of the strings arranged in parallel. Each string may have two to four electrolysers. The electrolyser unit 106 may comprise eight electrolysers 108 in total, with two parallel strings of four electrolysers 108, or four parallel strings of two electrolysers 108. Arranging the electrolysers 108 both in parallel and series may achieve a voltage across the electrolyser unit 106 that is similar to the bus voltage, which may avoid losses due to large voltage transformations. Examples of electrolyser units 106 having electrolysers 108 arranged both in parallel and series are illustrated in Figs. ID to II. Alternatively, the electrolysers 108 of the electrolyser unit 106 may be arranged only in series. The number of electrolysers arranged in parallel and / or in series can be any number of electrolysers.

[0019] The peak capacity of the electrolyser unit 106 is the peak capacity of all electrolysers forming part of the hydrogen generator module 100. In other words, the peak capacity of theelectrolyser unit 106 is the peak capacity of all electrolysers coupled to the DC bus 112 of the hydrogen generator module 100.

[0020] Each of the plurality of electrolysers can be controlled (switched on and off or regulated) independently from each other. This provides a more flexible deployment of the electrolyser unit 106 and a more efficient system by ensuring that the peak capacity of the electrolyser unit 106 closely matches the current capacity provided to the electrolyser unit 106. For example, an electrolyser unit 106 comprising five electrolysers 108, each of which having a peak capacity of 10 MW, may only have four of the five electrolysers switched on when the power provided to the electrolyser unit 106 is below 40MW. As another example, an electrolyser unit 106 comprising eight electrolysers 108, each of which having a peak capacity of 10 MW, may only have four of the eight electrolysers switched on when the power provided to the electrolyser unit 106 is below 40MW. The electrolyser(s) 108 within the electrolyser unit 106 may each have a peak capacity from 1 MW to 10 MW, optionally 3 MW to 10 MW. Each electrolyser unit 106 may comprise a plurality of cells connected in series.

[0021] The electrolyser(s) 108 may be any suitable type of electrolyser such, as but not limited to, an electrolyser unit 108 comprising a diaphragm, or an electrolyser unit 108 comprising a membrane, or an electrolyser unit 108 based on solid oxide, or an electrolyser unit 108 comprising a proton -conducting electrolysis cell. Electrolysers comprising a diaphragm can be of an alkaline water electrolysis type which is characterized by having two electrodes operating in a liquid alkaline electrolyte. Electrolysers comprising a membrane can be of a proton exchange membrane (PEM) electrolysis type, an anion exchange membrane (AEM) electrolysis type, or any other membrane electrolysis type. A membrane and a diaphragm are distinguished in that a diaphragm can withstand a certain amount of force or pressure, while a membrane can typically withstand on a very small force or pressure (if any at all). A membrane is a relatively thin partition (similar to a plastic film) and is typically not self-supporting.

[0022] A membrane type electrolyser (such as, a PEM, AEM or any other suitable electrolyser comprising a membrane) may be preferred over a diaphragm type electrolyser (such as an alkaline electrolyser or any other suitable electrolyser comprising a diaphragm) in that the membrane type electrolyser can be switched on and off quickly and does not need to be kept in a standby mode when not in use. The membrane type electrolyser maintains its high efficiency even when it is switched on and off frequently. For off-grid appliances, such as that of the present invention which is preferably not connected to a national power grid, this is advantageous because an unused electrolyser does not require any power. Such a scenario can easily come up in an off-grid arrangement powered solely by renewable energy sources, for example, when there is no wind and no solar.

[0023] In contrast, a diaphragm type electrolyser is most efficient when it is continuously run. Efficiency is reduced if a diaphragm type electrolyser is operated at less than about 50% of capacity. Therefore, an increase in efficiency can be achieved by utilising membrane type electrolysers in the electrolyser unit 106.

[0024] The electrolyser unit 106 is coupled to the pipeline 110 such that the pipeline 110 is configured to receive and store hydrogen gas from the electrolyser unit 106. The electrolyser unit 106 may be coupled directly to the pipeline or indirectly. For example, the electrolyser unit 106 may comprise an output pipe which is coupled directly to the pipeline 110 such that generated hydrogen gas directly fed into the pipeline 110. Alternatively, the output pipe of the electrolyser unit 106 may feed generated hydrogen gas into a service hub (as is described with reference to Figure 3 below) as an intermediary, before the generated hydrogen gas is fed into the pipeline 110. Output unit 119 is provided to remove oxygen as a by-product of the electrolysis (e.g. by venting to atmosphere) and polishing water output form the electrolyser for reuse. Output unit 119 can either be provided separately from electrolyser unit 106 (as illustrated in Figure 1A) or incorporated into the electrolyser unit 106 (as illustrated in Figures IB-11),

[0025] The electrolyser unit 106 generates hydrogen at a high pressure. In some arrangements this pressure may be up to and including 4000 kilopascal (kPa). The pipeline must be suitable to withstand equally high pressures of hydrogen gas to ensure that the generated hydrogen can be stored and transported throughout the pipeline safely without any leakage of hydrogen. Accordingly, the pipeline can be suitable to withstand pressures of at least 4000 kPa. In a preferred embodiment, the pipeline may be suitable to withstand pressures of at least 10000 kPa. An additional advantage of utilising a pipeline that can withstand a high pressure is that generated hydrogen can be stored in the pipeline 110 if the pipeline is of a certain length. This mitigates the need for a hydrogen storage tank and also provides a simple arrangement of delivering generated hydrogen from its source to where it is required.

[0026] The pipeline 110 may be a flexible pipe (such as, but not limited to, a polymer pipe). Advantageously, a flexible pipe easily be coiled up such that a single long pipe can be transported on a lorry. This is much easier and cheaper than using segments of a non-flexible pipe which typically come in a fixed size and require large lorries to carry the non-flexible pipe segments. Non-flexible pipes in segments also need to be carefully assembled to ensure that leakage is minimised which requires a lot of time and resources and still risks leakage at the point of assembly. This is mitigated entirely with the use of a single flexible pipe which can have as few as two assembly points (i.e. at the electrolyser unit 106 and at a distribution point) in lengths of up to 800 m. Further still, flexible pipes provide a more dynamic pipelaying ability by being able to lay pipes in any desired curvature. Therefore, one or more apparatuses 100 as described above can be placed in any arrangement and easily be connected by one or more pipelines 110 without complexengineering requirements of the pipeline. Further still, flexible pipes are easier to lay because a single lorry can comprise both a component to dig a trench as well as a component to directly lay the pipeline in the trench.

[0027] The pipeline 110 can have an internal diameter from 4 inches (about ten centimetres) to 8 inches (about twenty centimetres). As generated hydrogen gas from the electrolyser unit(s) 106 feeds into the pipeline, the pressure will increase in the pipeline 110 and the pipeline will act as a storage buffer up to the pressure capacity of the pipeline (e.g. at least 4000 kPa or at least 10000 kPa). The internal diameter of the pipeline 110 is chosen dependant on how many of the hydrogen generator modules 100 are attached to one pipeline 110 and the size of the wind turbine(s) 102, solar array(s) 104, and electrolyser unit(s) 106. The internal diameter may also be chosen dependent on the length of the pipeline 110, for example, to achieve a certain volume of the pipeline 110. It is advantageous to maintain a threshold pressure in the pipeline 110 e.g. using valve to prevent that the transmission compressor creates a vacuum in the collection pipes. Therefore, a smaller internal diameter may be preferred for a pipeline 110 coupled to fewer apparatuses 100 and / or apparatus(es) 100 with a smaller peak capacity. Similarly, a larger internal diameter may be preferred for a pipeline 110 coupled to multiple apparatuses 100 and / or apparatus(es) 100 with a larger peak capacity. The threshold pressure in the pipeline 100 may be maintained using a valve to prevent a compressor (to be described later) from creating a vacuum in a collector pipe (to be described later).

[0028] The length of the pipeline 110 may be predetermined dependent on the peak capacity of an electrolyser unit 106 (or a plurality of electrolyser units 106) coupled to the pipeline. For example, the pipeline 110 may have a length at least equal to 500 meters per 10 MW of the electrolyser peak capacity. This means that a hydrogen generator module 100 comprising an electrolyser unit 106 with a peak capacity of 10 MW will be coupled to a pipeline that is at least 500 meters long. Another hydrogen generator module 100 comprising an electrolyser unit 106 with a peak capacity of 20 MW would then be coupled to a pipeline that is at least 1000 meters long. This means that the pipelines 110 of the two apparatuses 100 would have a total length of at least 1500 meters, if they are coupled together. Providing a pipeline 110 of at least 500 meters per 10 MW of electrolyser peak capacity ensures that the pipeline 110 is long enough to work both as a hydrogen transport system as well as a hydrogen storage system. Furthermore, a minimum distance (for example, 1 kilometre) between apparatuses 100 can be maintained. The length of the pipeline 110 per MW can be adjusted to ensure more efficient storage and / or to meet transport demands and may preferably be at least 1 kilometre (km) per 10 MW of the electrolyser peak capacity, more preferably at least 1 km per 5 MW of the electrolyser peak capacity, and most preferably at least 500 meters per 1 MW of the electrolyser peak capacity.

[0029] Storing generated hydrogen in the pipeline 110 mitigates the need for a storage tank. There may be no storage tank provided between the outlet of the electrolyser unit 106 and the inlet of the pipeline 110. The pipeline 110 may extend continuously with no storage tank provided along the full length of the pipeline 110 between the outlet of the electrolyser unit 106 and the point of use of the generated hydrogen.

[0030] The wind turbine 102 of the hydrogen generator module 100 can have a wind peak capacity, that is a peak capacity of the wind of turbine, from 4 to 15 MW, preferably from 3 to 10 MW, more preferably from 5 to 10 MW, and most preferably from 6 to 8 MW. The wind peak capacity is the peak capacity of all wind turbines 102 forming part of the hydrogen generator module 100 (which may be a single wind turbine 102). In other words, the wind peak capacity is the peak capacity of all wind turbines 102 coupled to the DC bus 112 of the hydrogen generator module 100 (which may be a single wind turbine 102). Similarly, the solar array 104 can have a solar peak capacity, that is a peak capacity of the combination of solar panels of the solar array, from 3 to 14 MW, preferably from 3 to 10 MW, and more preferably from 5 to 10MW. The solar peak capacity is the peak capacity of all solar panels forming part of the hydrogen generator module 100. In other words, the wind peak capacity is the peak capacity of all solar panels coupled to the DC bus 112 of the hydrogen generator module 100. The wind peak capacity and the solar peak capacity may be a respective fraction of the peak capacity of the electrolyser unit 106. For example, the solar peak capacity may be 30 to 140%, optionally 50 to 140%, further optionally about 80%, of the peak capacity of the electrolyser unit 106, and the wind peak capacity may be 40 to 150%, optionally 80 to 150%, further optionally about 120%, of the peak capacity of the electrolyser unit 106. Accordingly, if the electrolyser unit 106 has a peak capacity of 10 MW, the solar array 104 may have a solar peak capacity of 8 to 14 MW and the wind turbine 102 may have a wind peak capacity of 12 MW. The fraction may be adjusted dependent on the location of the hydrogen generator module 100. For example, a location that experiences relatively more sunlight and less wind would favour a ratio for the solar array 104, whereas a location that experiences high wind and less sunlight would favour a higher ratio for the wind turbine 102. In most cases it is not anticipated that the solar and wind generation would be operating at maximum power simultaneously.

[0031] The electrolyser unit 106 may be powered by a dedicated wind turbine 102 and solar array 104. In other words, a majority (more than 50%) of the usable power generated by the wind turbine 102 and solar array 104 is used by the electrolyser unit 106. In arrangements having a supercapacitor and / or a battery (as described below), a majority of the usable power generated by the wind turbine 102 and solar array 104 may be used to power the electrolyser unit 106 and to charge the supercapacitor and / or battery.

[0032] As noted above, the wind turbine 102, solar array 104 and electrolyser unit 106 of the hydrogen generator module 100 may be coupled to a common DC bus 112 of an electric power distribution system. The electric power distribution system consists of the electrical components and / or equipment that cooperate to form electrical pathways between the wind turbine, the solar array and the electrolyser unit of the hydrogen generator module 100. The electric power distribution system may be internally exclusively DC coupled, such that, in the flow of electric power from the wind turbine and / or solar array to the electrolyser unit, there is no conversion of electric power from DC to AC. Such an arrangement avoids losses associated with conversion of electric power from DC to AC. In any of the arrangements described herein, the voltage in the DC bus may be maintained at less than 2000 V, optionally less than 1500 V.

[0033] In an arrangement, the wind turbine 102 and the solar array 104 of the hydrogen generator module 100 are electrically coupled to an input side of a direct current (DC) bus 112 in parallel. The electrolyser unit 106 of the hydrogen generator module 100 is coupled to an output side of the DC bus 112. Therefore, the wind turbine 102 and solar array 104 can simultaneously provide power in the form of a direct current to the electrolyser unit 106.

[0034] Solar and / or wind energy can be generated in bursts (for example, when there is a gust of wind) and can also experience slow-downs or short cut-offs of generation (for example, when a cloud is briefly blocking the sunlight). During those bursts, slow-downs, or cut-offs the amount of power fed into the DC bus 112 can vary. However, the power required by the electrolyser unit 106 to generated hydrogen remains the same. Therefore, there is a need to stabilise the power input into the electrolyser unit 106 to improve efficiency of hydrogen production.

[0035] A DC controller, a supercapacitor 114 (also known as an ultracapacitor), and a longer- term power storage device may also be coupled to the DC bus 112 to stabilise the power input into the electrolyser unit 106. Desirably, the voltage in the DC bus should be maintained at a target value on the range of from 200 V to 1500 V, more desirably in the range of from 1000 V to 1500 V. Electrolysers may be connected in series to match the bus voltage or in parallel with an extra DC:DC converter to reduce the bus voltage to the input level required by the electrolyser. The supercapacitor 114 is configured to stabilise intermittent power levels and / or store excess energy generated by the wind turbine 102 and / or the solar array 104 and to provide the excess energy to the DC bus 112 (and so, the electrolyser unit 106) when the power generated by the wind turbine 102 and / or the solar array 104 is below a threshold power value. The threshold power value is the power required by the electrolyser unit to generate hydrogen.

[0036] Supercapacitors provide a reliable means of storing and providing excess energy because of their ability to undergo frequent charge and discharge cycles at high current and short duration. Therefore, supercapacitors provide a simple way of controlling the voltage provided to the electrolyser unit 106 and, in particular, of smoothing the voltage provided to the electrolyser unit106. Thus, the DC bus 112 can provide (by the wind turbine 102, the solar array 104, and the supercapacitor 114) a current at the voltage that is available to the electrolyser. Supercapacitors can have an energy efficiency of up to 98% (that is, a maximal loss of no more than 2%) in comparison to regular capacitors or batteries as storage mechanisms. Therefore, a supercapacitor 114 coupled to the DC bus 112 in parallel can smooth voltage and current provided to the DC bus 112 and, thus, the electrolyser unit 106 with minimal waste of energy. Therefore, the efficiency of hydrogen production is increased. The supercapacitor 114 may have a peak capacity from 2 MWseconds to 4 MWminutes.

[0037] In an embodiment, the wind turbine 102, the solar array 104 and the supercapacitor 114 are configured to provide a DC at a predetermined voltage wherein the electrolyser unit 106 is configured to generated hydrogen with the DC at the predetermined voltage. The predetermined voltage may be less than 2000 V, optionally less than 1500 V.

[0038] In some scenarios, the power generated by the wind turbine 102 and / or the solar array 104 may substantially exceed the power that can be utilised by the electrolyser unit 106. In such a scenario, the supercapacitor 114 coupled to the DC bus 112 may already be fully charged which means that any excess power generated by the wind turbine 102 and / or the solar array 104 would go to waste. To prevent such power from going to waste, a battery 115 may also be coupled to the DC bus 112. The battery 115 may have a peak capacity from 1 MWhours to 20 MWhours, optionally 2 MWhours to 4 MWhours. The battery is configured to store excess energy when the excess energy stored by the supercapacitor 114 is above an energy threshold, the energy threshold may be the maximum amount of energy that the supercapacitor 114 can hold. The battery is configured to provide the excess energy as DC at the predetermined voltage when the power generated by the wind turbine 102 and / or the solar array 104 is below a low threshold power value.

[0039] The battery 115 may work in unison with the supercapacitor 114 by providing excess energy to the DC bus 112 simultaneously to the supercapacitor 114. Alternatively, the battery may discharge stored energy to the DC bus 112 when the power provided by the wind turbine 102 and / or the solar array 104 is below the threshold power value for a predetermined time. In that scenario, the supercapacitor 114 provides stored energy when the power generated by the wind turbine 102 and / or the solar array 104 is below the threshold for a time that is less than the predetermined time. More specifically, the supercapacitor 114 is able to smooth the power over short periods of time no longer than ten minutes and, more generally, on the order of seconds and / or milliseconds. Therefore, the predetermined time may be ten minutes, one minute, one second, or any value less than ten minutes depending on the size of the supercapacitor 114.However, if the power provided drops below the threshold power value for more than the predetermined time the supercapacitor can no longer efficiently smooth the power value. This may occur when there is no wind and / or no sun for a prolonged period of time (for example, at night orduring adverse weather). In such a scenario, the charged battery can provide the DC bus 112 with stored energy therein to maintain a DC current at the predetermined voltage at the DC bus 112 and, accordingly, for the electrolyser unit 106.

[0040] In place of a supercapacitor 114, a high-power battery (for example SuperBattery, from Skeleton Technologies) may be used in any of the arrangements described herein. A high-power battery or flywheel may be used in place of both the supercapacitor 114 and battery 115. in any of the arrangements described herein. A high-power battery or flywheel may provide both capacitor and battery functions, namely both power and energy stabilisation.

[0041] In an embodiment, the wind turbine 102 comprises a rectifier 116 operable to convert alternating current (AC) generated by the wind turbine 102 into DC at the predetermined voltage. For example, a wind turbine may generate AC at 1340 V and incorporate a rectifier that outputs at 1100 V DC.

[0042] In an embodiment, the solar array 104 comprises a DC to DC converter 118 electrically coupled to the at least one solar panel of the solar array 104. The DC to DC converter 118 may be a DC step-up converter, a DC step-down converter or a combination of the above. The DC to DC converter 118 is configured to step-up or step-down the DC voltage of the solar panel array to the predetermined voltage.

[0043] The solar array 104 may be provided with one or more photovoltaic (PV) combiner boxes 117 and one or more DC to DC converters 118, electrically coupled to the at least one solar panel of the solar array 104, as shown in Figures ID, IF and 1H. Alternatively, the solar array 104 may be provided with one or more string optimisers 125, electrically coupled to the at least one solar panel of the solar array 104, as shown in Figures IE, 1G and II. The DC to DC converters 118 or string optimisers 125 may be DC step-up converters, DC step-down converters or a combination of the above. The DC to DC converters 118 are configured to step-up or step-down the DC voltage of the solar panel array to the predetermined voltage

[0044] Desirably, the electrolyser unit 106 may be placed within a tower of the wind turbine 102. Accordingly, a pipe leading from the electrolyser unit 106 and coupled to the pipeline 110 may be underneath the wind turbine 102. Desirably the electrolyser 106 may be outside the wind turbine tower but the DC bus and rectifiers, etc. (power electrics) may be inside the tower.

[0045] In an embodiment, DC bus 112 may be connected to a power grid 124 via a small inverter 122, which may be a DC to AC or AC to DC inverter, to allow a relatively small amount of electricity to be imported and exported.

[0046] The description that follows describes the specific arrangements of Figures 1B-1I, in which the principles and concepts described above are applied, demonstrating their practical implementation in various configurations. Only differences between the arrangements of Figures1B-1I and the general arrangement described above will now be described. The arrangements of Figures 1B-1I may have any of the features described above.

[0047] The hydrogen generator module 100’ depicted in Figure IB differs from the hydrogen generator module 100 depicted in Figure 1A in that DC / DC converters are provided between the DC bus and each of the electrolysers 108. This means that the DC bus may be kept at a higher voltage, e.g. in the range of 1000 to 1500 V, than is acceptable as input to the electrolysers 108. Keeping the DC bus at a high potential may increase efficiency in conversion of input power from the wind turbine 102 and solar panels 104 as well as in transmission of power in the DC. Keeping the DC bus at a high potential may also increase efficiency in converting surplus power (e.g. power generated by the wind turbine and solar panels that is above the capacity of the electrolysers) to AC via DC / AC converter 122 for export to a power grid.

[0048] Figure 1C depicts a hydrogen generator module 100” which comprises: a single wind turbine 102 having a peak capacity of 6 MW; 10 solar arrays 104 each having a peak capacity of 500 kW and 5 electrolysers each having a peak capacity of 1 MW. The DC bus is maintained at a relatively high potential, e.g. 1,000 V. A boost converter 127 is provided to convert the output power from the wind turbine at ~ 600 V to 1000 V. Alternatively a buck converter that converts 1350 V AC to 1100 V DC may be used. A maximum power point tracking (MPPT) converter and / or buck converter 125 is provided for each solar array to bring the power down from ~ 1500 V to 1000 V. A buck converter 126 is provided for each electrolyser to bring the power down from 1000 V to the required input for the electrolysers, e.g. 200 to 460 V, optionally 200 to 320 V, which increasing the current.

[0049] To address power fluctuations, a power battery 123 and an energy battery 124 are provided. The power battery has a relatively low storage capacity, for example about 100 kWh, but a high maximum power output, for example about 500 kW whereas the energy battery has a relatively high storage capacity, for example about 400 kWh, but a lower maximum power output, for example about 400 kW. The power battery is therefore suitable for smoothing short term but significant power fluctuations whereas the energy battery is suitable for maintaining hydrogen output during longer gaps in solar or wind generated power.

[0050] Figures 1D-1I depict hydrogen generator modules 100 following different operating philosophies. Each of the arrangements depicted in Figures 1D-1I has a DC bus 112 (optionally a DC busbar). The variations illustrated in Figures 1D-1I are the same as one another, differing only in the following aspects, to be described further below: whether the voltage of the bus varies based on the voltage of the electrolyser unit, or is maintained in a fixed range; whether a supercapacitor is directly or indirectly connected to the bus; and whether certain components are grouped so as to be electrically coupled to the bus by a common switch.

[0051] In the arrangements of Figures ID, IF, and 1H the voltage of the DC bus 112 is variable. In the arrangements of Figures ID, IF, and 1H, the voltage of the DC bus 112 follows the voltage of the electrolysers 108, for example in the range of 500-1000 V, optionally 640-920 V. The bus bar 112 voltages of the hydrogen generator modules 100 depicted in Figures IE, 1G and II are kept at the fixed predetermined level above 1400 and below 1500 volts.

[0052] In each of the designs of Figure ID, IE, IF and 1G, a supercapacitor 114 is optionally directly connected to the DC bus 112. In each of the designs of Figure 1H, II, a supercapacitor 114 is optionally connected in between the wind turbine 102 and wind AC-DC converter 116, such that the supercapacitor 114 is coupled to the bus 112 via the wind AC-DC convertor 116.

[0053] In each of the designs of Figure 1D-1I, DC-DC converters are provided between the battery 115 and the DC bus 112, and DC-DC convertors (or string optimisers) are provided between the solar array 104 and the DC bus 112. In the arrangements of Figures IE, 1G and 1H, DC-DC convertors are provided between the DC bus 112 and the electrolyser unit 106. Each DC- DC convertor unit depicted may be a DC-DC convertor stack, as opposed to a single DC-DC convertor.

[0054] The electrical design of the hydrogen generator modules 100 depicted in Figures ID, IE is different from that depicted in Figures IF, 1G, 1H and II. In the design of the modules 100 of Figures IF, 1G, 1H and II, the wind turbine 102, the wind turbine converter 116, battery 115 and supercapacitor 114, battery DC to DC converter 120, auxiliary inverter 122 and auxiliary services 130 are connected to the DC bus 112 by a common switch. This enables these components to be isolated and operate independently from the rest of the system in case of system instability. In general, the wind turbine 102, the battery 115 and supercapacitor 114 may be electrically coupled to the DC bus 112 by a common switch to permit isolation in the case of system instability.

[0055] Optionally, auxiliary services 130 e.g. cooling and lighting, may be receive power from the DC bus 112 and / or an external power grid via an auxiliary inverter 122.

[0056] An energy output of a single hydrogen generator module 100, according to any of the arrangements described herein, may be more than 30 Gigawatt hours (GWh), preferably more than 40 GWh. In other words, an amount of energy used annually by the electrolyser unit of a single hydrogen generator module 100 to generate hydrogen may be more than 30 Gigawatt hours (GWh), preferably more than 40 GWh. The energy / hydrogen output may be scaled up by providing more than one hydrogen generator module 100, as discussed further below.

[0057] A plurality of the hydrogen generator modules 100 as set out above with reference to Figures 1A to II (below referred to as units lOOx, wherein ‘x’ denotes any letter of the alphabet) can be coupled together to both increase the amount of hydrogen that can be produced and also increase the amount of hydrogen storage (by way of the length of pipelines 110). Figures 2 to 14 show a number of different example arrangements of a plurality of units lOOx coupled to eachother. The plurality of units lOOx described may be identical or may be different. This means that a unit 100a may have an identical electrolyser unit 106 to a unit 100b. Alternatively, unit 100a may have a different electrolyser unit 106 to that of unit 100b (and so forth, applied to all of the features described above with reference to Figure 1A to II).

[0058] Figure 2 shows an example system 200 for generating and storing hydrogen gas comprising two units 100a and 100b coupled directly to the same pipeline 110. In other words, the pipeline 110 is shared between units 100a and 100b. Figure 2 is not limited to two units and can comprise any number of units lOOx coupled directly to the same pipeline 110.

[0059] Figure 3 shows an alternative example system 300 for generating and storing hydrogen gas comprising four units 100a to lOOd coupled to a service hub 302. The service hub 302 separates the generated Oxygen gas from the electrolysis process and collects the oxygen gas. This may then be distributed into a separate pipeline or released into the air. The service hub 302 also collects any unused water from the electrolysis process of each of the electrolyser units 100 of each unit 100a to lOOd and polishes this water so that it can be re-used for future electrolysis processes. The service hub 302 subsequently sends the polished water back to the units 100a to lOOd and, more specifically, back to the electrolyser units of the units 100a to lOOd. The service hub 302 may also be directly coupled to the electrolyser units of the four units 100a to lOOd on an input side and directly coupled to the pipeline 110 on an output side. Thus, the service hub 302 may be operable to collect generated hydrogen from each of the four units 100a to lOOd and to feed the collected hydrogen gas to the pipeline 110. Alternatively, the pipes of each of the four units 100a to lOOd are directly coupled to the pipeline 110. This example is not limited to four units and may comprise at least one unit 100a coupled to the service hub 302. A service hub 302 having n units connected to the service hub 302, may occupy an area of up to (lOw + 100) ha, without including the spaces between the units 100a. In other words, each unit 100a may occupy up to 10 ha, and the service hub 302 may occupy up to 100 ha. For a system having 100 units 100a, the service hub 302 and all units 100a coupled to the service hub may occupy an area of up to 1100 ha, without including the spaces between the units 100a.

[0060] Figure 4 shows a system 400 which is a modified version of the example system 200 shown in Figure 2. In Figure 4, units 100a and 100b are directly coupled to a first pipeline 110a as described in Figure 2. Furthermore, a third unit 100c and a fourth unit lOOd are directly coupled to a second pipeline 110b. In other words, the third unit 100c and the fourth unit lOOd do not share the same pipeline as the first unit 100a and the second unit 100b. The arrangement of Figure 4 is not limited to two units per pipeline. Instead, that arrangement can comprise a first unit 100a directly coupled to a first pipeline 110a, and a third unit 100c coupled to a second pipeline 110b. Alternatively, any number of units lOOx can be coupled to the first pipeline 110a and any number of units lOOx can be coupled to the second pipeline 110b.

[0061] Service hub 302 in the system of Figure 4 is identical to the service hub 302 in the system of Figure 3 except that the service hub 302 of Figure 4 is not directly coupled to the electrolyser units of the four units 100a to lOOd. However, the service hub 302 may be coupled to units coupled to a first pipeline 110a and to units of a second pipeline 110b. The service hub 302 may be coupled to units lOOx that are directly coupled to any number of pipelines 1 lOx.

[0062] Figure 5 depicts a large-scale system 500 which comprises a plurality of parallel pipelines 1 lOa-d each of which is connected to a plurality of systems 300 as described above with reference to Figure 3. Parallel pipelines 1 lOa-d supply hydrogen output by systems 300 to a collector pipe 502 that collects all the generated hydrogen and supplies it to compressor station 504. It will be appreciated that parallel pipelines 1 lOa-d are schematically parallel and need not be physically parallel on the ground. Compressor station 504 compresses the collected hydrogen and supplies it to a transport pipeline 506 which transports the hydrogen to the delivery point, e.g. at the point of use. Compressor station 504 may increase the pressure of the hydrogen from about 4000 kPa in parallel pipelines 1 lOa-d to at least 10000 kPa in transport pipeline 506. Transport pipeline 506 may act as additional storage of hydrogen and hence may count towards the total pipeline length required per unit of electrolysis generation in the large scale system as described above. In other words the total length of parallel pipelines 1 lOa-d and transport pipeline 506 should exceed 500 meters per 10 MW of the total electrolyser peak capacity in large scale system 500.

[0063] An ammonia cracker or small grid-connected electrolyser 508 may be provided to provide a small amount of additional to-up hydrogen in case of need. Whilst connecting grid connections to multiple hydrogen generator modules 100 distributed across a wide area may be expensive, a single grid connection to an electrolyser 508 co-located with the compression station may be relatively inexpensive.

[0064] Figure 6 depicts a large-scale system 600 which is similar to the system of Figure 5 except that it comprises a plurality of parallel pipelines 1 lOa-h pairs of which are connected to a plurality of systems 400 as described above with reference to Figure 4. This arrangement provides a greater length of pipeline 110 per hydrogen generator module 100 and so may be appropriate where the hydrogen generator modules 100 have a higher peak capacity or are closer together.

[0065] Figure 7 depicts a large-scale system 700 which is similar to the system of Figure 6 except that the compression station 504 and optional grid-connected electrolyser 508 are centrally located. Whilst still providing the same length of pipeline per hydrogen generator module 100, the average distance between the hydrogen generator modules 100 and the compression station is reduced therefore the energy cost in collecting the hydrogen is reduced.

[0066] Figure 8 depicts a large-scale system 800 in which a large number of hydrogen generation modules 100, e.g. 50 to 100 in number, are connected to a relatively small number of pipelines 110, e.g. 3 to 10 in number. The collector pipelines are sized in accordance with the number andcapacity of the hydrogen generation modules 100 and may have an internal diameter of, for example, 4 to 8 inches or equivalent. The pipelines 110 connect to a connector pipeline 502 to bring the generated hydrogen to a central compressor, which may be coupled to an ammonia cracker or small grid-connected electrolyser. This arrangement can provide > 1 km pipeline per 1 MW of hydrogen production capacity.

[0067] Figure 9 depicts a large-scale system 900 in which groups of units 100, e.g. 20 to 30 in number, share a common services network 303 and a hydrogen compressor 504 which pressurises the generated hydrogen for feeding into a transport pipeline 506. Several groups, e.g. 2 to 5 in number, may supply one transport pipeline. This arrangement may suit locations where there are several smaller areas suitable for disposition of the wind turbines and solar arrays.

[0068] Figure 10 depicts a large-scale system 1000 similar to that of Figure 9 but in which the hydrogen compressor 504 and services 302 are centrally located with the field of solar arrays. This arrangement can reduce the average distance between hydrogen generator and compressor, thus reducing the energy cost of collecting the hydrogen without reducing the overall storage capacity.

[0069] Figure 11 depicts a large-scale system 1100 comprising more than 100, e.g. 150 - 250, hydrogen generator modules 110 each having its own services unit 302. Groups of hydrogen generator modules 100, e.g. about 100 modules, are connected to respective compressors 504 via pipelines 110. In this arrangement, pipelines 110 are not straight but follow curved routes to the respective compressor 504. Having curved pipelines enables the disposition of the pipelines to be adapted to the landscape and provides flexibility to ensure sufficient pipeline length on average for storage purposes. The services units 302 are interconnected with water pipelines 310.

[0070] Figure 12 depicts a large-scale system 1200 similar to the system 1100 depicted in Figure 11 except that clusters, e.g. of four, hydrogen generator modules 110 are connected to each services unit 302.

[0071] Figure 13 depicts a large-scale system 1300 in which groups, e.g. of 20 to 30, of hydrogen generator modules 110 are connected to a centrally located services unit 302. Each group is also connected to a compressor 504 to deliver hydrogen to the transmission pipeline 506. As with Figures 11 and 12, pipelines 110 are not straight but follow curved routes to the respective compressor 504.

[0072] Figure 14 depicts a large-scale system 1400 which has large groups of hydrogen generator modules 100, for example each group may have 50 to 150 hydrogen generator modules 100, connected to central services 302 and a hydrogen compressor 504. As with Figures 11, 12 and 13, pipelines 110 are not straight but follow curved routes to the respective compressor 504.

[0073] It will be appreciated that other interconnection arrangements may be used as desired. In many cases the arrangement of hydrogen generator modules 100 may be influenced by local geographic factors, such as the direction of prevailing winds and the slope of the land, as well asfactors related to the solar array and wind turbines chosen, e.g. minimum spacings to avoid wake effects. In some cases, the physical separation of the hydrogen generator modules 100 or system 300, 400 may be such that shortest route interconnections provide sufficient length of pipeline to provide storage. In other cases, indirect or meandering paths for the pipelines 110 may be employed to increase the length of pipeline. It is noted that in a large system, it is not necessary that there is a desired minimum length of pipeline between each generator module and the compressor, only that the average length of pipeline per generator module is of the desired minimum. Coils of pipeline may also be used to increase the storage capacity.

[0074] Having described exemplary embodiments of the invention, it will be appreciated that the invention may be put into practice in other ways, including using variations and equivalents of the described embodiments. The scope of the invention is defined by the appended claims.

Claims

CLAIMS1 . An apparatus for generating and storing hydrogen gas comprising: a wind turbine; a solar array comprising at least one solar panel; an electrolyser unit comprising one or more electrolysers, the electrolyser unit having an electrolyser peak capacity and powered by the wind turbine and / or the solar array; and a pipeline, configured to receive and store hydrogen from the electrolyser unit and having a length at least equal to 500 metres per 10 Megawatt (MW) of the electrolyser peak capacity, wherein the wind turbine, the solar array and the electrolyser unit are electrically coupled to a common direct current (DC) bus of an electric power distribution system.

2. The apparatus of claim 1, wherein the electrolyser peak capacity of all electrolysers coupled to the DC bus is from 3 to 50 MW.

3. The apparatus of claim 1 or 2, wherein the length of the pipeline is: at least 1 kilometre (km) per 10 MW of the electrolyser peak capacity; preferably at least 1 km per 5 MW of the electrolyser peak capacity; more preferably at least 0.5 km per 1 MW of the electrolyser peak capacity.

4. The apparatus of any preceding claim, wherein the wind turbine has a wind peak capacity from 4 to 15 Megawatt (MW), preferably from 3 to 10 MW, more preferably from 5 to 10 MW, and more preferably from 6 to 8 MW.

5. The apparatus of any preceding claim, wherein the solar array has a solar peak capacity from 3 to 14 MW, preferably from 3 to 10 MW, and more preferably from 5 to 10 MW.

6. The apparatus of any preceding claim, wherein the apparatus has a total electrolyser peak capacity of all electrolysers coupled to the DC bus of 3 to 50 MW, a total wind peak capacity of all wind turbines coupled to the DC bus of 4 to 15 MW, and / or a total solar peak capacity of all solar panels coupled to the DC bus of 3 to 14 MW.

7. The apparatus of any preceding claim, wherein the apparatus has a single wind turbine for powering the electrolyser unit.

8. The apparatus of any preceding claim, wherein the electrolyser unit, wind turbine and solar array are co-located within an area of less than 10 hectare (ha).

9. The apparatus of any preceding claim, wherein the electrolyser comprises a membrane.

10. The apparatus of any preceding claim, wherein the electrolyser unit comprises a plurality of electrolysers arranged in parallel or in series.11 . The apparatus of claim 10, wherein the plurality of electrolysers can be switched on and off independently from each other.

12. The apparatus of any preceding claim, wherein the pipeline has a diameter from four inches (ten centimetres) to eight inches (twenty centimetres).

13. The apparatus of claim 12, wherein the pipeline is a flexible pipe.

14. The apparatus of any preceding claim, wherein the hydrogen is generated at 4000 kilopascal (kPa) and wherein the pipeline is suitable to withstand at least 4000 kPa, and preferably at least 10000 kPa.

15. The apparatus of any preceding claim, wherein the electric power distribution system is internally exclusively DC coupled, such that, in the flow of electric power from the wind turbine and / or solar array to the electrolyser unit, there is no conversion of electric power from DC to AC.

16. The apparatus of any preceding claim, wherein the voltage in the DC bus is maintained at less than 2000 V, optionally less than 1500 V.

17. The apparatus of any preceding claim, further comprising: a supercapacitor, or another electrochemical device capable of storing energy with an efficiency above 95%, configured to store excess energy generated by the wind turbine and / or the solar array and to provide the excess energy when the energy generated by the wind turbine and / or the solar array is below a threshold energy value; wherein the DC bus is configured to electrically couple the wind turbine, the solar array and the supercapacitor, or the other electrochemical device, directly to the electrolyser unit in parallel.

18. The apparatus of claim 17, wherein the wind turbine, the solar array and the supercapacitor, or the other electrochemical device, are configured to provide a direct current (DC) at a predetermined voltage and wherein the electrolyser unit is configured to generate hydrogen with the DC at the predetermined voltage, wherein the predetermined voltage is less than 2000 V, optionally less than 1500 V.

19. The apparatus of claim 18, further comprising: a battery coupled to the DC bus and configured to store excess energy when the excess energy stored by the supercapacitor, or the other electrochemical device, is above a threshold, wherein the battery is operable to provide the excess energy in a DC at the predetermined voltage when the energy generated by the wind turbine and / or the solar array is below the threshold energy value.

20. The apparatus of claim 19, wherein the battery provides excess energy when the energy provided by the wind turbine and / or the solar array is below the threshold energy value for a predetermined time and wherein the supercapacitor, or the other electrochemical device, provides excess energy when the energy generated by the wind turbine and / or the solar array is below the threshold for a time that is less than the predetermined time.21 . The apparatus of claims 14 to 20, wherein the wind turbine comprises first circuitry operable to convert alternating current (AC) generated by the wind turbine into DC at the predetermined voltage, wherein the first circuitry comprises a rectifier to convert the alternating current to direct current.

22. The apparatus of claim 21 : wherein the solar panel array comprises second circuitry electrically coupled to the at least one solar panel, wherein the second circuitry comprises a DC step-up converter, a DC stepdown converter or a combination of the above and the second circuitry is configured to step-up or step-down the DC voltage of the solar panel array to the predetermined voltage; or wherein the solar panel array is electrically coupled to the first circuitry and the first circuitry comprises a DC step-up converter, a DC step-down converter or a combination of the above and the first circuitry is configured to step-up or step-down the DC voltage of the solar panel array to the predetermined voltage.

23. The apparatus of any preceding claim, wherein the wind turbine comprises a tower and the electrolyser unit is within the tower of the wind turbine.

24. The apparatus of any one of claims 17 to 23, wherein the threshold energy value is the energy required by the electrolyser unit to generate hydrogen.

25. A system for generating and storing hydrogen gas comprising: two apparatuses as set out in claims 1 to 24, wherein the pipeline is shared by the electrolyser units of the apparatuses.

26. The system of claim 25, further comprising: a third apparatus as set out in claims 1 to 24, wherein the pipeline of the third apparatus is not shared with the pipeline of the first and second apparatuses.

27. The system of claims 25 or 26 further comprising: a distribution pipe; and a gas compression station coupled to the pipelines on an input side of the gas compression station and coupled to the distribution pipe on an output side of the gas compression station, the gas compression station is operable to: receive the generated hydrogen gas from the pipelines; compress the generated hydrogen gas to a threshold pressure; and feed the compressed hydrogen gas to the distribution pipe.

28. The system of claim 27, further comprising: a collector pipeline directly coupled to each of the pipelines and directly coupled to the gas compression station, wherein the collector pipe is operable to receive generated hydrogen gas from the pipelines and to feed the generated hydrogen gas to the gas compression station.

29. The system of claim 23 or 28, further comprising a service hub coupled to at least two electrolyser units, and the service hub is operable to: collect oxygen gas from the at least two electrolyser units; polish water used by the at least two electrolyser units; and send the polished water back to the at least two electrolyser units.

30. The system of claim 29, wherein the service hub is coupled to one of the pipelines and is operable to collect the hydrogen from the at least two electrolyser units and to feed the collected hydrogen gas to that pipeline.31 . The system of claims 27 to 30, wherein the threshold pressure is at least 3000 kilopascal (kPa), preferably at least 4000 kPa, and most preferably at least 10000 kPa.

32. The system of claims 27 to 31, wherein the two apparatuses and, optionally, the third apparatus are coupled to the gas compression station in a star arrangement such that the gas compression station is located centrally relative to the apparatuses.

33. A method of generating and storing hydrogen gas comprising: generating, at a wind turbine and a solar array comprising at least one solar panel, energy: receiving, at an electrolyser unit comprising one or more electrolysers, the generated energy; generating, by the electrolyser unit, hydrogen gas with the generated energy; and receiving and storing the generated hydrogen gas in a pipeline, wherein: the electrolyser unit has an electrolyser peak capacity, the pipeline has a length at least equal to 500 metres per 10 MW of the electrolyser peak capacity, and the wind turbine, the solar array and the electrolyser unit are electrically coupled to a common direct current (DC) bus of an electric power distribution system.

34. The method of claim 33, wherein an amount of energy used annually by the electrolyser unit to generate the hydrogen is more than 30 Gigawatt hours (GWh), preferably more than 40 GWh.

Images