Hydrogen production plant comprising photovoltaic panels

Abstract

The hydrogen production plant (100) comprises: - a field (4) of photovoltaic panels (6); - at least one electrolyser (8) located in the field and configured to produce hydrogen and to be supplied with electrical current by the photovoltaic panels; and - a device (10) for treating hydrogen, the device being located at a distance from the field less than or equal to a largest dimension (D) of the field.

Description

[0001] Hydrogen production facility including photovoltaic panels

[0002] FIELD OF THE INVENTION

[0003] The invention relates to the production of hydrogen using electrolysers supplied with electric current by photovoltaic panels.

[0004] STATE OF THE ART

[0005] Hydrogen can be produced by electrolysis of water using electrolyzers powered by photovoltaic panels. This is one of the means of producing so-called "green" hydrogen, given the use of a renewable energy source to supply the electricity. The photovoltaic fields are connected to an electricity transmission network, to which the electrolyzers producing the hydrogen are also connected. The transition from direct current electricity at the panel level to alternating current electricity (transformation, network) leads to the use of power electronics equipment such as inverters (DC / AC).

[0006] However, the cost price of this green hydrogen is high. We are currently seeking to lower it to a level between €1.5 and €2.5 / kg and even between €0.7 and €1.5 / kg. To achieve this, we are seeking to reduce the cost of the necessary investments, which constitute a major part of the calculation of the price of hydrogen, and also to improve the efficiency of the overall system.

[0007] One aim of the invention is therefore to reduce the cost of producing hydrogen.

[0008] STATEMENT OF THE INVENTION

[0009] For this purpose, the invention provides a hydrogen production installation comprising:

[0010] - a field of photovoltaic panels; and

[0011] - at least one electrolyser located in the field and configured to produce hydrogen and to be supplied with electric current by the photovoltaic panels. Thus, thanks to the reduced distance between the electrolyser and the panels, a high level of integration of the photovoltaic system and the electrolysis system is achieved and significant cost savings are obtained. In particular, the invention makes it possible to reduce the lengths of the electric cables. Better efficiency is also obtained by reducing the Joule effect losses with equal copper cross-section

[0012] The invention notably allows the development of giga photovoltaic fields supplying electrolysers in order to produce green hydrogen (for example several hundred tonnes per day) to meet demand from local industries wishing to decarbonise, particularly steelworks. These developments are conditioned, for example, by a target hydrogen price of around 1.5 euros per kilo or even less than 1 € per kilo. The invention makes it possible to achieve such an ambitious target.

[0013] It also allows the development of smaller photovoltaic fields, of the order of several tens of megawatts supplying electrolysers of the same order of power to produce several tens of tonnes of green hydrogen per day.

[0014] On the electrolysis side, electrolyzer suppliers are considering unit stack power (a stack being a stack of anodes and cathodes to produce the electrochemical reaction of water electrolysis) of up to ten megawatts of power in the medium term. An electrolyzer can include several stacks associated with one or more separators, all controlled by a control system integrating the electrical part, the process part (water, hydrogen and oxygen) and the interfaces with the support functions (air, nitrogen, cooling network, etc.).

[0015] The invention notably allows for a scale effect on the systems connected to the electrolyser (called Balance of Plant (BOP) in English). Upstream, this concerns the power supply and the demineralized water supply. Downstream, this concerns hydrogen treatments such as deoxygenation, dehydration and compression, and also functions such as the electrolyser cooling system. The invention is particularly applicable for the conversion of existing photovoltaic fields whose electricity purchase contract is expiring and must be renegotiated. For example, centralized hydrogen production to meet a need for clean mobility with associated charging stations could prove economically more attractive than selling kilowatt-hours on the network in competition with other energy suppliers seeking to sell it at the same time, provided that they also have photovoltaic energy.

[0016] The invention is applicable in areas with high levels of sunshine, for example in Spain. It concerns power levels ranging from 5 MW to several hundred, this power being that of the panels and / or electrolysers.

[0017] In the context of the invention, one or more electrolysers are located in the field, but it is possible that the installation also includes one or more other electrolysers connected to the panels and located outside the field. They will then, for example, be located at a distance from the latter less than a larger dimension of the field.

[0018] It can be expected that the installation includes at least two electrolysers, in particular at least two electrolysers in the field.

[0019] It can be planned that the or each electrolyser is located in a central area of ​​the field.

[0020] This area represents, for example, 50%, 25% or 10% of the field area.

[0021] Advantageously, the installation comprises at least a first electrolyser and a second electrolyser, the installation being configured so that:

[0022] - the first electrolyser is supplied with electric current by a first group of photovoltaic panels and

[0023] - the second electrolyser is supplied with electric current by a second group of photovoltaic panels.

[0024] The installation can be expected to include at least two electrolysers, with at least one of the panels being interposed between the two electrolysers. Such a decentralized architecture of the electrolysers is counterintuitive given the desired scale effect and the market. However, it does have advantages. By separating the electrolysers from the rest of the installation (balance of plant), an advantage is obtained in the conveyance of energy to the latter, for example, located in the center of the field. Indeed, when the electrolysers were centralized, the conveyance of energy within the installation was mainly done from the photovoltaic panels to the electrolysers and therefore in the form of electrical cables.In the presence of such a decentralized architecture of the electrolysers, the energy conveyance is now mainly done from the electrolysers to the hydrogen treatment device and therefore in the form of pipes for transporting this gas. This transport can take place either with the gas in its raw state as generated by the electrolyser, or after an initial treatment (this can then be improved water separation and / or deoxygenation, or even dehydration). This proves economically interesting for the investment and more efficient because there is less energy loss in the conveyance. This makes it possible to reduce the cables (length and section) by placing the consumer (the electrolyser) as close as possible to the production source (the panel).Centralization, especially for fields of 100 MW and above, now only concerns other functions such as water pretreatment, hydrogen post-treatment (deoxygenation and / or dehydration), its compression and storage. By connecting the electrolyzers to this last part by a network of pipes conveying the hydrogen and water vapor produced (there may also be traces of oxygen), the pressure losses are much lower in energy terms than losses due to the Joule effect in electrical cables. The installation becomes more efficient. Since the electrolyzers are dispersed within the field, the integration between the production and consumption of electricity is further improved.

[0025] The installation may be provided to comprise at least two electrolysers which extend at a distance from each other greater than half of a largest dimension of the field.

[0026] The electrolysers may be provided to form an assembly larger than half of a larger dimension of the field. The or each electrolyser may be provided to be connected to the panels without interposition between the electrolyser and the panels of a power electronics component.

[0027] The invention also makes it possible to avoid the use of power electronic equipment such as inverters (DC / AC), which further contributes to reducing initial investments. This also results in efficiency gains since this type of equipment consumes energy and generates losses through the Joule effect.

[0028] It is also possible to use DC / DC type power electronics equipment.

[0029] It may be provided that the installation comprises a hydrogen treatment device, the device being located at a distance from the field less than or equal to a largest dimension of the field.

[0030] The device can be predicted to be in the field.

[0031] The device can be expected to be outside the field. For example, the device may be several kilometers from the field.

[0032] For example, the function of compressing the hydrogen gas produced could be implemented at a great distance from the field while at least one post-treatment function (dehydration for example) would take place in the field or in the vicinity of the latter.

[0033] For example, the device is located in a central area of ​​the field.

[0034] In one embodiment, the installation comprises at least two electrolysers and the device is located between the two electrolysers.

[0035] The invention also provides a method for producing hydrogen in which photovoltaic panels forming a field supply electric current to at least one electrolyser producing hydrogen and located in the field.

[0036] DESCRIPTION OF THE FIGURES We will now present two embodiments of the invention as non-limiting examples in support of the drawings in which:

[0037] - figures 1 and 2 are diagrams of a first embodiment of an installation according to the invention;

[0038] - figures 3 and 4 are two views similar to figures 1 and 2 illustrating a second embodiment of the invention; and

[0039] - Figure 5 is a diagram of the hydrogen treatment device in each of these embodiments.

[0040] We will present two embodiments of the invention. These are two different architectures of photovoltaic-electrolysis integration.

[0041] First embodiment

[0042] We will describe with reference to figures 1 and 2 a first embodiment of the installation 100 according to the invention. This mode preferably corresponds to a small photovoltaic field.

[0043] The hydrogen production facility 100 comprises a field 4 of photovoltaic panels 6. Figure 1 is a diagram of the spatial arrangement of the elements of the facility 100. The proportions of ground surface in this diagram are close to reality. Each square represents for example a portion of land of one hectare carrying photovoltaic panels 6, for example tens, hundreds or up to 3000 panels for example.

[0044] Figure 2 illustrates their electrical and fluid connections in summary form, without respect for spatial arrangement or proportions. The connections are incomplete, in particular the electrical connections. It is understood that in Figure 2 only a small number of panels 6 have been represented.

[0045] The field 4 here has a rectangular shape but multiple other geometric shapes, possibly non-planar depending on the relief of the terrain, can be envisaged: square, circular, triangular, etc. It can be a field in several disjoint portions. The field 4 has a larger geometric dimension D measured in this case along a diagonal of the rectangle. The installation also comprises several electrolysers 8 represented here in common by a block in Figures 1 and 2. Each electrolyser 8 is configured to produce hydrogen and oxygen. The installation 100 comprises for this purpose means for supplying the electrolysers with water.

[0046] As illustrated in Figure 2, the electrolysers 8 are supplied with electric current by the panels 6. The connection between the panels and the electrolysers is made by direct current. Different electrical assemblies are possible for this purpose that the person skilled in the art will be able to foresee. In particular, it can be provided that all the panels supply all the electrolysers in common or that respective separate groups of panels supply the respective electrolysers.

[0047] Figure 1 shows that the electrolysers 8 are located in the field, and in this case in a central area of ​​the field. The electrolysers 8 are therefore located between some of the panels 6. This arrangement reduces the Joule effect losses, the wiring connecting the panels 6 to the electrolysers 8 being generally shorter than in a situation in which the electrolysers 8 are located outside the field, even close to the latter, for example at a distance from the field 4 less than or equal to the largest dimension D, and even less than 50% and 80% of the latter.

[0048] It is also possible to provide, as a variant, that certain electrolysers 8 are located outside the field but close to the latter, for example at a distance from the field 4 less than or equal to the largest dimension D, and even less than 50% and 80% of the latter.

[0049] The installation 100 comprises a device 10 for processing and compressing / storing the hydrogen produced by the electrolysers 8. Such a device is conventional and will not be detailed here. Downstream of the electrolysers, the device 10, as illustrated in FIG. 5, performs the processing and compression / storage of the hydrogen by means of the following successive functions: separation with the residual water 16, deoxygenation 18, drying (dehydration) 20, compression 22, storage 24. The electrolysers 8 are connected to the central processing device 10 by one or more conduits 16 conveying untreated hydrogen to the latter. The device 10 contains at least the deoxygenation 18 and drying (dehydration) 20 functions.

[0050] The device 10 is located in this case within the sub-assembly 12 ensuring the centralized functions of the installation (balance of plant). The device 10 and the sub-assembly 12 of which it is part are also located in the field and even in the central zone, as illustrated in Figure 1.

[0051] Furthermore, the oxygen also produced by the electrolysers can be released immediately into the atmosphere or treated and stored.

[0052] The installation also includes upstream a demineralization unit (not shown) which allows to purify the water supplying each electrolyzer 8 to remain below a predetermined maximum conductivity and ion content. It also includes a cooling unit, centralized or not, which allows to extract calories from the system, mainly those generated by electrolysis. The latter is an endothermic reaction but the Joule effects are predominant. This unit allows to stabilize the temperature within the electrolyzers between 50 and 90°C, or between 80°C and 100°C, for example. In one variant, it can be provided that the cooling is provided by air exchangers on each electrolyzer. In another variant, it can be provided that the cooling is provided as close as possible to the electrolyzer(s) in the photovoltaic field and as close as possible to the hydrogen treatment and compression / storage system.

[0053] All elements of the installation, in particular the panels 6 and the electrolysers 8, can be commercially available elements.

[0054] This installation makes it possible to implement the hydrogen production process in which the photovoltaic panels 6 forming the field 4 supply electric current to the electrolysers 8 producing hydrogen. The installation may comprise automated control means for controlling this process.

[0055] Second embodiment We will now describe, with the support of figures 3 and 4, an installation 200 forming a second embodiment. It is identical to the previous one except for the following characteristics.

[0056] This time, the electrolysers 8 are no longer in the centre but are dispersed and distributed throughout the field. As shown in Figure 3, many panels 6 are each interposed between two of the electrolysers 8. The electrolysers are here distributed throughout the field 4 so that some of them extend at a distance F from each other greater than half of the largest dimension D of the field, or even greater than 75 or 80% of the latter.

[0057] The panels 6 are connected to each other in disjoint groups. Four groups Mari are illustrated in Figure 4, more in Figure 3. The installation comprises a much higher number of groups, for example several hundred. There are as many groups as electrolysers 8 and the latter are associated with the respective groups and only one of them, therefore bijectively. Thus, a first electrolyser 8 is supplied with current by a first group of the panels 6, a second electrolyser 8 is supplied with current by a second group of the panels 6, and so on.

[0058] The electrolysers 8 are connected to the central processing device 10 by conduits 16 conveying the hydrogen (untreated, i.e. raw) to the latter. In this embodiment, in addition to the scale effects from which the functions related (drying, for example dehydration, deoxygenation, etc.) to the electrolysis can benefit, the installation provides a decentralized configuration where the electrolysers are distributed in the photovoltaic field, making it possible to convey the energy to the central zone via the network of raw hydrogen pipes 16 and not in the form of electric current. There is also, in terms of safety, a reduction in the “domino” effects compared to a solution where the electrolysers are centralized (for example under the same building). In such a case, in fact, the proximity between the electrolysers can cause an incident such as an explosion on one to spread to the neighbors. This disadvantage is avoided here by the distance between the electrolysers.

[0059] In each of these embodiments, the connection between the panels 6 and the electrolysers 8 is made without going through a regional or national electricity transmission and distribution network. Similarly, the installation is each time devoid of DC / AC power electronics.

[0060] Many modifications can be made to the invention without departing from its scope.

Claims

Demands 1. Hydrogen production facility (100; 200) comprising: - a field (4) of photovoltaic panels (6); - at least one electrolyzer (8) located in the field and configured to produce hydrogen and to be supplied with electric current by the photovoltaic panels; and - a hydrogen processing device (10), the device being located at a distance from the field less than or equal to a larger dimension (D) of the field.

2. Installation according to the preceding claim in which the electrolyzer or at least one of the electrolyzers (8) is located in a central area of ​​the field.

3. An installation according to any one of the preceding claims comprising at least one first electrolyzer (8) and a second electrolyzer (8), the installation being configured such that: - the first electrolyzer is supplied with electric current by a first group of photovoltaic panels (6) and - the second electrolyzer is supplied with electric current by a second group of photovoltaic panels (6).

4. Installation according to any one of the preceding claims comprising at least two electrolyzers (8), at least one of the panels (6) being interposed between the two electrolyzers (8).

5. Installation according to any one of the preceding claims comprising at least two electrolyzers extending at a distance (F) from each other greater than half of the largest dimension (D) of the field.

6. Installation according to any one of the preceding claims in which the electrolyzer or each electrolyzer (8) is connected to the panels (6) without interposition between the electrolyzer (8) and the panels (6) of a power electronics component.

7. Installation according to any one of the preceding claims wherein the device (10) is located in the field (4).

8. Installation according to any one of the preceding claims wherein the device (10) is located in a central area of ​​the field.

9. Installation according to any one of the preceding claims comprising at least two electrolyzers and wherein the device (10) is located between the two electrolyzers (8).

10. A process for producing hydrogen in which: - photovoltaic panels (6) forming a field (4) supply electric current to at least one electrolyzer (8) producing hydrogen and located within the field; and - a device (10) treats the hydrogen produced by the electrolyzer (8), the device being located at a distance from the field less than or equal to a larger dimension (D) of the field.

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