WO2024160971A1

WO2024160971A1 - Large-scale green hydrogen production system for producing hydrogen, ammonia and/or other potential hydrogen derivatives

Info

Publication number: WO2024160971A1
Application number: PCT/EP2024/052535
Authority: WO
Inventors: Guido Schumacher
Original assignee: Cwp H1 Energy Pte Ltd
Current assignee: Cwp H1 Energy Pte Ltd
Priority date: 2023-02-01
Filing date: 2024-02-01
Publication date: 2024-08-08
Anticipated expiration: 2025-08-01
Also published as: DE102023102503A1

Abstract

A Large-scale green hydrogen production system (100') for producing hydrogen, ammonia and/or other potential hydrogen derivatives, comprise: - wind turbines (11) and photovoltaic modules for generating electrical power; - an electrolyzer for generating hydrogen from the electrical power; - an interconnector for interconnecting the wind turbines (11) and photovoltaic panels with the electrolyzer; - a control system for controlling the wind turbines (11), the photovoltaic modules and the electrolyzer; - a wide area network comprising a plurality of power generating upstream nodes (10.1', …,10.10'), wherein: - each upstream node (10.1', …,10.10') comprises a wind turbine (11), a photovoltaic module and an electrolyzer unit and wherein the wind turbine(s) (11), the photovoltaic module(s) and the electrolyzer unit are electrically interconnected by an on-site electrical distribution network (14); - the upstream nodes (10', 10.1', …, 10.10') are linked via interconnectors (20; 20') with a hydrogen transport pipeline (22) to a downstream power utilization node (30) and/or a hydrogen storage facility and/or a hydrogen shipping facility (port 31) and/or a hydrogen processing unit.

Description

Large-scale green hydrogen production system for producing hydrogen, ammonia and/or other potential hydrogen derivatives

The invention relates to a large-scale green hydrogen production system for producing hydrogen, ammonia and/or other potential hydrogen derivatives, comprising at least: a plurality of wind turbines and a plurality of photovoltaic modules for generating electrical power; an electrolyzer for generating hydrogen from the electrical power; an interconnector for interconnecting the wind turbines and photovoltaic panels with the electrolyzer; and a control system for controlling the wind turbines, the photovoltaic modules and the electrolyzer.

Hydrogen is considered to be the energy carrier of the future because it can be burned without producing any pollutants. It is also possible to generate electricity from hydrogen with little local effort by using a fuel cell. To improve transportability over long distances, it is known to react hydrogen with nitrogen to produce ammonia, which can be liquefied at higher temperatures than elemental hydrogen, facilitating transport in tanks on ships or trains. Hydrogen is produced on a large scale and economically by electrolysis of water. The electricity required for electrolysis should be provided by

SUBSTITUTE SHEET (RULE 26) renewable energy generation. Hydrogen produced in this way is called "green hydrogen".

Renewable energy with a capacity comparable to that of conventional power plants is currently generated mainly by wind turbines or photovoltaic systems. The well-known disadvantages of not being able to generate electricity during a calm period for a wind turbine or during darkness for a photovoltaic system are at least reduced by the formation of hybrid systems that have both wind turbines and arrays of photovoltaic cells.

US2022/112107A1 describes a hydrogen production system in which multiple wind turbines and photovoltaic systems are combined with electrolysis units. These and other system components are controlled by a system controller. In addition to producing hydrogen that is stored locally, the gaseous hydrogen produced during electrolysis is also captured and stored. The stored gases can be used to generate electricity on demand via a fuel cell. This system is intended for local use.

US 2008/0127646 A1 discloses a system and method for hydrogen production. It combines multiple wind turbines and solar panels with electrolysis units to produce hydrogen. All plant components are controlled by a common system controller to optimize the overall system for hydrogen yield. The hydrogen produced will be used locally to process fossil fuels or sold in compressed form, which requires transportation. Hydrogen can also be used to generate electricity on demand. Surplus electrical energy is to be supplied via the existing high-voltage grid.

Coastal regions in Africa or South America have good climatic conditions to produce green energy from wind and solar power, and are often unpopulated or sparsely populated, so that a very large number of wind turbines and solar power plants could be built there. However, the aforementioned system is not arbitrarily scalable; it cannot be economically expanded to very large dimensions of several hundred or even thousands of square kilometers because the electrical lines within the system would have to be very long. Very long high-voltage transmission lines would have to be constructed and maintained to transport the electrical energy to populated areas or other areas where the electrical energy can be used for production. High-voltage transmission lines constructed as overhead lines also have transmission losses of about 10% over a length of 800 km. In addition, additional grid stabilization equipment would have to be provided, requiring, for example, constantly controlled power consumption on the consumer side or even more expensive buffers. Scaling the known system to a region with an extension of more than 100 km2 is therefore not economically feasible.

The object of the invention is therefore to specify a hydrogen production system to produce green hydrogen which can be operated economically in large-scale projects and is optimized with respect to the yield of hydrogen obtained from renewable energy.

This object is solved by a large-scale green hydrogen production system for producing hydrogen, ammonia and/or other potential hydrogen derivatives having the features of claim 1 .

The term "large scale" is defined as a distance that is too long to make it economically feasible to connect distributed power generation units, such as wind turbines and photovoltaic panel arrays, directly to a utilization node, such as a hydrogen storage unit and/or a hydrogen transport unit and/or a hydrogen processing unit. Such a distance is typically greater than 10 km. Therefore, the typical area of application for such a production system is an entire region of a country that has access to large amounts of water, such as coastal regions or regions bordering large inland lakes.

In the large-scale green hydrogen production system proposed by the invention, a network topography is formed in the available region from a plurality of individual subzones, each of which has at least one power generation node or hub formed therein. In such a node, referred to as an upstream node, as many plant components as possible are bundled and placed in close proximity to each other to keep the lengths of electrical power lines short. In particular, photovoltaic modules and electrolysis units are arranged side by side at the power generation node, while some wind turbines associated with the node may be positioned somewhat further apart in order to reduce mutual interference between adjacent wind turbines and to be able to select optimal locations for each wind turbine with respect to the terrain topography.

According to the invention, the connection of the power generating upstream nodes to each other as well as to at least one power utilization node is not necessarily established via a high-voltage AC electrical line, but primarily via a connecting line comprising at least one hydrogen pipeline. Thus, the energy generated at an upstream node is not, or at least not only, transported in the form of electrical energy, but primarily in the form of hydrogen gas.

The connecting pipelines between several upstream nodes and at least one energy-consuming downstream node form an interconnection network, which is basically a pipeline network for transporting hydrogen and which can be equipped with other lines running in parallel along the same route.

As a first important advantage, the construction of such an interconnection network with at least one hydrogen pipeline over long distances is cheaper and more scalable compared to a high-capacity electrical overhead line. A hydrogen pipeline is usually built on stilts in sparsely populated areas on a route that is needed for a connecting road anyway. The better scalability of a gas interconnector results from the fact that the intended production and storage pressure can be easily increased by simply increasing the wall thickness, with the cost of increased pipe wall thickness being low compared to the construction of the route for the pipeline, which is needed to access the nodes anyway. If there is a future need for increased pumping capacity, another pipeline can be added along the same route. Downstream sections of the interconnected network can be designed for greater capacity than upstream sections, whereas overhead power lines would have to be designed for maximum transmittable power over their entire length, and increased capacity would only be possible by pulling more cables into the existing poles or even by building a parallel second line.

Power for ancillary equipment such as compressors located along the interconnector can be provided much more easily by installing a valve on the pipeline to draw some hydrogen from the pipeline for a fuel cell, which is much less expensive than a transformer unit attached to a high-voltage power line.

Remote inspection and maintenance of long gas pipelines, e.g., by pigging, is well established and can be automated, making it much less expensive than inspecting a high-voltage power line, which requires, among other things, visual inspection, and maintenance by helicopter.

Another advantage of the internal connection between the nodes by means of a pipeline network rather than an electrical line is that a fresh water pipeline can also be laid in the interconnection route, although in this case the direction of flow is reversed, i.e. towards the upstream nodes. The fresh water supply is needed for hydrogen production by electrolysis and for cooling the produced gas, compressors, etc. As a side effect, the water pipelines can also be used to supply inhabited farm buildings at the nodes and small settlements and agricultural areas along the route.

In this context, it may be advantageous to provide a third pipeline to transport the water heated by the electrolysis process away from the nodes. This is an option if the system is located in sunny and windy but cool regions. The heat can be used for heating nearby settlements and agricultural facilities, especially greenhouses. In addition, excess heat can be used for de-icing pumps, pipelines, etc. A particular advantage of the network topography according to the invention is that the pipeline itself can be used as a storage and buffer. In periods when both wind and solar energy are available, the hydrogen produced at each node can be stored by simply increasing the pressure in the pipeline. During periods of low hydrogen production, the stored hydrogen gas can be used to feed the hydrogen processing equipment at a constant volume flow and at a minimum pressure, e.g., to produce ammonia from the hydrogen in an energy utilization node, since ammonia is easier to liquefy and therefore easier to transport by ship or rail.

A coordinated operation of the hydrogen production in the multiple power generation nodes by a superordinate system controller is possible, but not necessary according to the invention since the pipeline connection between the multiple nodes via a hydrogen line compensates local pressure fluctuations or even temporary production failures of individual nodes.

Due to the electrical independence of an upstream node from other nodes in the surrounding area, an on-site electrical network can be established at each energy production node, in which voltage, frequency and current are optimized only locally to operate the node's electrolysis units with the highest possible hydrogen yield. It is therefore no longer necessary to convert the direct current generated by photovoltaic modules or wind turbines into AC with the usual grid frequencies of 50 Hz or 60 Hz. Much higher frequencies such as 400 Hz or even 1000 Hz can be used for AC power within each node. The cost and weight of standard components required in the internal grid, especially transformers, can be reduced,

Since electrolysis takes place directly in the upstream nodes, there are no power losses due to transformation and frequency conversion. As a result, no complex electrical equipment is required in an upstream node. At the node, transformers and inverters are provided only for low power to power motors, controls, pumps, and lighting within the node. Generated electrical power can be used directly for hydrogen generation in an upstream node, according to the invention, photovoltaic modules are preferably positioned directly adjacent to the electrolysis equipment, and the size of a node is such that the distance between the associated wind turbines and the electrolysis equipment is less than 20 km. Thus, the generated electricity can be transmitted to the electrolyzer with reasonable cable crosssections.

Another particular advantage is that the interconnection via hydrogen transport interconnectors does not only work downstream, i.e. , on the way from the upstream hydrogen generating nodes to at least one downstream plant. The interconnection also allows individual nodes to be supplied upstream, so that hydrogen can be drawn from the interconnection network to provide an emergency power supply to an upstream node, e.g., via a fuel cell.

The interconnection of nodes by means of a wide-area interconnection network, in which hydrogen gas flows instead of electricity, thus allows the operation of additional equipment in the course of the interconnections, such as compressors, which may be required outside the boundaries of the upstream nodes along pipeline sections. Such compressor units can be operated by drawing hydrogen locally from the pipeline and thus providing the electrical energy required to operate pumps and compressors by a locally installed fuel cell.

The invention will be explained in more detail below with reference to the exemplary embodiment shown in the drawings. The figures show in detail:

Fig. 1 a first example of a topography of a green hydrogen production system;

Fig. 2 a second example of a topography of a green hydrogen production system;

Fig. 3 an exemplary power generation node in plan view; Fig. 4 an exemplary energy utilization node in plan view;

Fig. 5 a functional diagram of a green hydrogen production system according to a first embodiment;

Fig. 6 a functional diagram of a green hydrogen production system according to a second embodiment; and

Fig. 7 a diagram with different parameters plotted over time

Figure 1 shows a first example of a green hydrogen production system 100, which is distributed over a coastal region 1 of a country. In the example, the maximum extension in the north-south direction is about 50 km and in the east-west direction about 250 km. The power generation system 100 comprises a total of 24 upstream power generation power generating nodes 10.1 , ..., 10.24 and one power utilization node 30 located downstream, at a sea 2 or lake. The lines between the power generation nodes 10.1 , ..., 10.24 indicate area boundaries of each node. The dots within the boundaries each represent a wind turbine 11 , each of which is electrically connected to the respective adjacent power generation node in the area.

The power generation nodes 10.1 ,10.24 and the power utilization node 30 are interconnected by a network of an interconnector 20 comprising at least one hydrogen pipeline. At the same time, especially in previously undeveloped parts of the region 1 , the route built for the interconnector 20 can be used to construct a parallel roadway.

A main line of an interconnector 20 extends from the far north-east power generation node 10.1 , ... , 10.24 to the power utilization node 30. The connection of the individual power generation nodes 10.1 , ...,10.24 to the interconnector 20 can be made in various ways:

- The easternmost power generation nodes 10.1 , 10.2, 10.3, 10.4 are connected directly to the main line of the interconnector 20. - Some power generation nodes, such as the westernmost power generation nodes 10.21 , 10.22, 10.23, 10.24, are interconnected in a group of four by a branch interconnector 29.1 running in a north-south direction. At a crossing point, the branch line is connected to the main line. In addition, another group of four nodes is connected by a branch interconnector 29.2 running in a north-south direction.

- At the power generation nodes 10.9, ...,10.12 a Y-shaped branch interconnector is provided. The power generation nodes 10.9, 10.10 are connected to the power generation node 10.11 , from which the branch interconnector extends to the power generation node 10.12. At the intersection of the branch interconnector 29.4 with the main line of the interconnector 20, the connection is made.

Figure 2 shows a second, smaller and simplified example of a power generation facility serving as a green hydrogen production system 100' which is also established in the coastal region 1 of the country located near the sea 2. It consists of ten power generation nodes 10.T, ..., 10.10’. Each power generation node 10. T , ... , 10.10’ is associated with an area of about 20 km x 20 km. A plurality of wind turbines 11 , each represented by a dot, are arranged in the area of the nodes 10. T, ..., 10.10’ and are electrically connected to their associated power generating upstream node. In this example, each power generation upstream node 10.T, ...,10.10' is connected via its own spur line to a main line of an interconnector 20' extending from east to west to a power utilization node 30 at sea 2.

Figure 3 shows an example of a single power generating upstream node 10 in plan view. This is designed such that several central units are placed within an arrangement of four rectangular arrays of photovoltaic modules 12. The central units include an electrolyzer 13, a battery module 16, and a central station 19 in which controls and accommodations for personnel, among other things, are located. The photovoltaic modules 12 are electrically connected to each other and to the central units by an on-site electrical distribution network. The wind turbines 11 associated with the power generation node 10 are also electrically connected thereto; the electrical connection lines extending from the wind turbines 11 to the central units are shown as dashed lines in Fig. 3.

The central units are positioned along an interconnector 20 that includes a hydrogen pipeline 22 shown as a dotted line, a freshwater pipeline 21 shown as a dash-dotted line, and a high voltage electrical power line 23 shown as a solid line. A roadway 24 shown as a double line is located along the interconnector 20.

Figure 4 shows an example of a downstream energy utilization node 30 in plan view. It is a complex of facilities built near the sea 2. The energy utilization node 30 includes a port 31 , a seawater desalination plant 32, and an ammonia plant 33. In addition, other facilities are located in a central station 35. The energy utilization node 30 is connected to the network of interconnectors 20 and parallel roads 24. Hydrogen produced in the upstream power generation nodes 10 is pumped through the hydrogen pipeline 22 to the ammonia plant 33. The liquid ammonia produced there is loaded onto ships at the port 31 . The seawater desalination unit 32 obtains seawater from the sea 2 via a tap line 36. The fresh water obtained from this is, on the one hand, supplied to the ammonia plant 33 as cooling water and, on the other hand, pumped upstream via the fresh water pipeline 22 within the connecting line 20 to supply the electrolysis plants in the upstream nodes 10.

Without reference to any possible topography, Figure 5 shows a functional diagram of a simple form of power generation plant 100', such as that shown in Figure 2. Two functionally identical power generating upstream nodes 10' are shown in the left panel, each comprising:

- a plurality of wind turbines 11 ;

- a plurality of photovoltaic modules 12;

- an electrolyzer 13; and - an on-site electrical distribution network 14 through which the wind turbines 11 , photovoltaic modules 12, and electrolyzer 13 are connected within the node.

For example, each upstream node 10 is configured such that the connected wind turbines 11 and photovoltaic modules 12 generate 1 GW of power at peak, with most of the power being used in the electrolysis process. In an exemplary configuration, the total renewable power generation is divided into similar upstream nodes 10 of 1 GW each. Each upstream node 10 is consists of the following elements:

- - 500 MW wind,

- - 500 MW solar,

- - 650 MW of water electrolysis co-located with the arrays of photovoltaic modules 12.

The power generating upstream nodes 10' are each connected to a connecting pipeline 20', which includes a hydrogen pipeline 22'. Through this pipeline, the hydrogen extracted from the electrolyzer 13 of the upstream node is delivered downstream. It can be used:

- to produce hot briquetted iron (HBI) from iron ore 40 in an HBI plant 34,

- to produce ammonia in an ammonia plant 33, which can be liquefied and easily transported by ship through a port 31.

- to be stored in tanks 37 or to be directly liquefied and transported by ship.

Also associated with the energy utilization node 30 is the seawater desalination unit 32, through which fresh water is pumped upstream through the freshwater pipeline 21 to the node 10.

Hydrogen consuming units may be installed along the interconnector 20 or are centralized in the downstream node 30. For example, to operate a seawater desalination unit 32 operating on the principle of reverse osmosis, engines fed with hydrogen or ammonia can be used. In the embodiment of a simple green hydrogen production system 100' shown in Fig. 5, the interconnector 20’ does not include a high voltage electrical line. Thus, the energy produced in the upstream nodes 10’ is only conducted through the hydrogen pipeline 22’ in the form of the locally produced hydrogen. The only electrical connections in this green hydrogen production system are provided by the on-site electrical distribution network 14 which is spanned within each of the power generating upstream nodes 10.

Figure 6 is a functional diagram of a more complex green hydrogen production system 100 with a higher level of equipment. Two functionally identical power generating upstream nodes 10 are shown in the left panel, each of which includes:

- multiple wind turbines 11 ;

- multiple arrays of photovoltaic modules 12;

- an electrolyzer 13;

- an on-site electrical distribution network 14 connected via a transformer 15 to a high-voltage electrical power line 23 as part of the wide area network provided by the interconnector 20;

- a flow battery 16 for long-term buffering of any of the units conected to the internal electrical distribution network 14;

- a lithium-ion battery 17 for short-term buffering and/or stabilization of the on-site electrical distribution network 14;

- a rotor inertia storage unit 18 for stabilizing the frequency of the on-site electrical distribution network 14.

With such a configuration the operation of the power generating upstream node 10 can be extended to periods of both low wind speed and low solar energy and is more failure safe hence. Reserve capacities of electrical power and hydrogen gas are stored with in the node and can be used to continuously operate all control systems, the substation, the compressors, and the cooling equipment for the electrolyzer and the compressors. Eventually the stored power can also be used to maintain the electrolysis process running at low level, too.

A rotor inertia storage unit 18 provides stability within the on-site electrical distribution network 14 during short periods of approximately 1-3 minutes of interruption of power generation.

The power generating upstream nodes 10 are each connected to the interconnector 20, which includes the fresh water pipeline 21 , the hydrogen pipeline 22, and a high-voltage electric line 23. Via the hydrogen pipeline 22, the hydrogen obtained from the electrolysis unit 13 of the node is supplied to the energy utilization node 30, where it can be utilized in the same manner as previously described with reference to Fig. 5.

An excess of electrical power which cannot be processed on-site at the electrolyzer 13 of the power generating upstream node 10 can be supplied to the electrical high voltage network to be consumed at any energy consuming downstream node 30. Still, the on-site generation of hydrogen and the control of the system of the green hydrogen production system 10 via hydrogen gas delivery retains priority over electrical power generation to be distributed over long distance lines.

The objective of a preferred method of operating the green hydrogen production system 100 is to provide stable conditions for operating a hydrogen consuming unit at the downstream node such as the ammonia plant.

Figure 7 is a diagram in which various parameters are plotted over a 24-hour period. All parameters are scaled to percentage values. A dotted line 5 represents the solar energy that is collected by arrays of photovoltaic modules 12 on a cloudless day. A dotted line 3 represents the wind energy harvested by wind turbines 11 during the day. Both energy sources together result in the production of a quantity of hydrogen by electrolysis. The pressure in the hydrogen pipeline is illustrated as a continuous line 6. Since the pipeline serves as a storage unit low hydrogen production e. g. during the night can be compensated by increased production during the middle of the day.

A dot-dashed line 4 refers to the pressure at an outlet of the ammonia processing unit 33. The normal ammonia output is 80% of the maximum pressure output. The curve 4 representing the ammonia output is constant over the entire 24-hour period because the hydrogen pipeline grid being part of the interconnector 20 is used as a buffer which levels the fluctuating volume of hydrogen produced.

Reference signs:

1 coastal region

2 sea

3 diagram line referring to wind energy harvest

4 diagram line referring to ammonia output

5 diagram line referring to solar power

6 diagram line referring to hydrogen pressure in the pipeline

100; 100’ green hydrogen production system

10; 10.1 , ..., 10.24; upstream nodes

10’, 10.1’,... ,10.10’

11 wind turbines

12 photovoltaic modules

13 electrolyzers

14 on-site electrical distribution networks

15 transformer

16 battery module

17 lithium-ion battery

18 rotor inertia storage unit

19 central station

20; 20’ interconnector

21 fresh water line

22 hydrogen pipeline

23 electrical high voltage power line

24 roadway

25’ compressor unit

29.1 , 29.2, 29.4 branch interconnector

30; 30’ power utilization node

31 port

32 water desalination unit

33 ammonia processing unit

34 HBI plant

35 substation

36 tap line

37 tank

40 iron ore

Claims

1 . Large-scale green hydrogen production system (100; 100’) for producing hydrogen, ammonia and/or other potential hydrogen derivatives, comprising at least: a plurality of wind turbines (11 ) and a plurality of photovoltaic modules (12) for generating electrical power; an electrolyzer (13) for generating hydrogen from the electrical power; an interconnector for interconnecting the wind turbines (11 ) and photovoltaic panels (12) with the electrolyzer (13); a control system for controlling the wind turbines (11 ), the photovoltaic modules (12) and the electrolyzer (13); characterized in that:

- the green hydrogen production system (100; 100’) has at least one wide area network comprising a plurality of energy generating upstream nodes (10, 10.1 , 10.2, ... , 10.24; 10’, 10.1 ’, ... ,10.10’)

- each upstream node (10, 10.1 , 10.2, ... , 10.24; 10’, 10.1’, ... ,10.10’) comprises at least one wind turbine (11) and one photovoltaic module (12) and one electrolyzer unit (13) wherein the wind turbine(s) (11 ), the photovoltaic module(s) (12) and the electrolyzer unit(s) (13) are electrically interconnected by an on-site electrical distribution network (14) spanned within the node (10, 10.1 , 10.2, ... , 10.24; 10’, 10. T, ... ,10.10’);

- the upstream nodes (10, 10.1 , 10.2, ... , 10.24; 10’, 10. T, ... , 10.10’) are linked via interconnectors (20; 20’) which each comprise a hydrogen transport pipeline (22) to a downstream power utilization node (30) and/or a hydrogen storage facility and/or a hydrogen shipping facility (port 31 ) and/or a hydrogen processing unit. 2. The green hydrogen production system (100; 100’) of claim 1 , wherein at least one upstream node (10, 10.1 , 10.

2, ... , 10.24; 10’, 10. T, ... ,10.10’) comprises a battery module (16) connected to the on-site electrical distribution network (14) and/or a rotor inertia storage unit (18)

3. The green hydrogen production system (100; 100’) of claim 1 or 2, wherein at least some upstream nodes (10, 10.1 , 10.2, ... , 10.24; 10’, 10.T, ... ,10.10’) comprise an electrical transformer (15) by means of which the on-site electrical distribution networks (14) of the upstream nodes (10, 10.1 , 10.2, ... , 10.24; 10’, 10.T, ... ,10.10’) are interconnected by a high voltage electrical power line (23).

4. The green hydrogen production system (100; 100’) of claim 3, wherein the high voltage electrical power line (23) is connected to the downstream node (30).

5. The green hydrogen production system (100; 100’) of any of the preceding claims, wherein the hydrogen processing unit in the downstream node (30) is an ammonia processing unit (33) and/or a Hot Briquetted Iron (HBI) plant (34).

6. The green hydrogen production system (100; 100’) of any of the preceding claims, wherein the downstream node (30) comprises a seawater desalination unit (32) which is connected to the water pipeline (21 ), to a seawater intake and to a salt brine disposal unit.

7. The green hydrogen production system (100; 100’) of any of the preceding claims, wherein the distance between adjacent upstream nodes (10, 10.1 , 10.2, ... , 10.24; 10’, 10. T, ... ,10.10’) or between an upstream node (10, 10.1 , 10.2, ... , 10.24; 10’, 10. T, ... , 10.10’) and the downstream node (30) is larger than 10 km.

8. The green hydrogen production system (100; 100’) of any of the preceding claims, wherein at least one upstream node (10, 10.1 , 10.2, ... ,

10.24; 10’, 10.1’, ... ,10.10’) comprises a water supply unit for cooling the electrolyzer (13).

9. The green hydrogen production system (100; 100’) of any of the preceding claims, wherein a hydrogen storage and/or buffer is provided by the hydrogen transport pipeline (22).

10. The green hydrogen production system (100; 100’) of any of the preceding claims, wherein the interconnector (20; 20’) comprises the hydrogen pipeline (22) and a freshwater pipeline (21) which connects a seawater desalination unit (32) located in the energy utilization node (30) with at least one upstream node (10, 10.1 , 10.2, ... , 10.24; 10’, 10. T, ... ,10.10’).

11 . The green hydrogen production system (100; 100’) pursuant to claim 10, wherein the interconnector (20; 20’) comprises a high voltage electrical power line (23).