Energy production and storage system

Abstract

An energy production and storage system comprising an electrical power input connection (10) for a renewable energy source (2); an electrolysis device (16) for electrolysis of water to produce oxygen, hydrogen and heat; an electrical energy storage device (14); a bidirectional grid connection (12) coupled to an external electrical grid (4); and a controller (8). The controller (8) is configured to: (i) receive information relating to actual or potential energy production of the renewable energy source (2), reserve energy in the electrical energy storage device (14) and balancing demand of the external electrical grid (4); (ii) use energy of the renewable energy source (2) to power the electrolysis device (16) and / or store in the energy storage device (14); and (iii) based on the received information, operate the energy production and storage system as a balancing service provider by either of: drawing electrical power from the grid (4) to supply the electrolysis device (16), or supplying electrical power from the electrical energy storage device (14) to the grid (4), thereby acting as a switch to assist in balancing the external electrical grid (4).

Description

[0001] This invention relates to energy production and storage systems, and more specifically, to systems that utilize energy from renewable energy sources and produce hydrogen, oxygen, and heat through the electrolysis of water. The invention also relates to methods for energy production control, such as methods related to grid balancing and energy storage.

[0002] There are many known systems for producing energy, especially electricity. Recently, increasing energy production from renewable energy sources has become increasingly attractive, for example, due to environmental, economic, and political reasons. However, problems arise for many renewable energy sources due to significant variations in energy production under different weather conditions or other external factors. This leads to a supply-demand mismatch. This is typically addressed by connecting to the grid to provide “supplementary” power when renewable energy cannot meet all instantaneous demand. When there is a power surplus, either the “free” energy from renewable energy sources is not used, or in some cases, the system is configured to allow bidirectional grid connections so that energy can be sold back to the grid when local energy production exceeds local energy demand.

[0003] Recently, there have been proposals to combine renewable energy production with local energy storage systems, particularly the ability to produce hydrogen and other substances using electricity in chemical processes. This approach allows for a more efficient match between local energy production and consumption. For example, US2011081586 discloses a separate system combining renewable energy production with the electrolysis production of hydrogen / oxygen and the storage of hydrogen as an energy carrier. For instance, when renewable energy cannot meet local energy demand, the stored hydrogen can be used as a fuel cell to increase power output. This eliminates dependence on grid connections. WO2022014766 also discloses the combination of renewable energy and electrolysis, in this case, with aquaculture, where the oxygen produced by electrolysis is used for fish farming. Hydrogen is produced and stored locally, then used locally as a fuel cell to generate electricity. This electricity, along with electricity from other sources such as solar energy, is used for temperature control in the fish farm.

[0004] From a first aspect, the present invention provides an energy production and storage system, comprising: - Power input connection for receiving electricity from renewable energy sources; - Electrolysis device, used to electrolyze water to produce oxygen, hydrogen and heat; - Energy storage devices; - Power grid connection, configured for bidirectional connection to receive power from and supply power to an external power grid; and - A controller that communicates with the power input, electrolysis unit, energy storage device, and power grid, wherein the controller is configured to: (i) Receive information relating to: actual or potential energy production from renewable energy sources, energy reserves in energy storage devices, and the balance demand of the external power grid; (ii) Using energy from renewable energy sources to power the electrolysis unit and / or storing it in an energy storage device; and (ii) Based on the received information, the energy production and storage system is operated as a balancing service provider in either of the following ways: drawing power from the external grid to supply the electrolysis unit, or supplying power from the energy storage unit to the external grid, thereby acting as a switch to assist in balancing the external grid.

[0005] By combining the use of renewable energy and electrolysis with the ability to provide balancing services, advantages are offered in improving the efficient utilization of renewable energy in synchronous power grids. This, in turn, enhances the benefits of renewable energy. Simultaneously, the system can produce "green hydrogen," i.e., hydrogen produced 100% from renewable energy, and can also extract excess (preferably renewable) energy from the grid when needed (e.g., for balancing purposes) using an electrolysis unit. In this way, the invention can also be extended to a renewable energy system comprising the energy production and storage system of the first aspect, and renewable energy (or multiple renewable energy sources) and / or one or two external power grids configured to supply renewable energy. This will distinguish it from non-renewable energy from the external grid, i.e., preferably a grid capable of distributing electrical energy from renewable energy for use by the energy production and storage system of the first aspect.

[0006] Therefore, in addition to all the advantages of existing technology systems combining renewable energy and electrolysis, there is an additional benefit of providing switching effects to aid external grid balancing, such as grid balancing related to automatic or manual frequency reserve capacity (e.g., Frequency Restoration Reserve (FRR) or Fast Frequency Reserve (FFR) systems), especially for balancing renewable energy resources on the grid. The switching effect depends on the size of the electrolysis unit and the associated size of the energy storage unit. The storage capacity and discharge rate of the energy storage unit enable it to provide peak power at least equal to the power required to operate the electrolysis unit, or its peak power may be one-half, one-quarter, or one-tenth of the power required to operate the electrolysis unit. If the energy storage unit can provide a load equivalent to that provided by the electrolysis unit (e.g., x With a power output of MW, the switching effect can be ± x MW, of which, xTypically, the value can range from 1MW to 150MW or higher. For example, for an electrolysis unit (or unit group) that requires 5MW and an energy storage unit that can provide 5MW (usually only for short bursts to balance the grid), the switching effect will be ±5MW, that is, providing a bidirectional switching effect, in which 5MW can be drawn from the grid or 5MW can be supplied to the grid.

[0007] Referring to (iii) above, to provide enhanced balancing capability, the controller can also be configured to: store electricity from the grid in an energy storage device to increase the peak power drawn from the grid; and / or supply power to the grid from a renewable energy storage device to increase the peak power supplied to the grid. Advantageously, the stored electricity from the grid is drawn from renewable energy sources. Therefore, for example, if the output of the renewable energy source is at least equal to the power output capacity of the energy storage device, the switching effect can be greater than ± x MW (for example, can be at least ±2) x (MW). It should also be understood that the controller can be configured to change the flow of (renewable) electricity to or from the grid, thereby allowing for finer control over the balancing effect.

[0008] The controller can be configured to receive power supply condition information related to grid capacity. This could include, for example, the cost of grid power supply. Renewable energy and / or energy storage devices can be used to supply / input electricity to the grid, not only for reasons related to grid balance but also based on considerations such as grid electricity trading prices. In this regard, trading prices reflect not only commercial considerations but also technical information, such as the relative availability of renewable electricity as weather conditions change. The grid can provide renewable energy, i.e., renewable energy from other parts of the grid. The controller's considerations could include assessing the relative pricing of renewable energy from the grid versus non-renewable energy from the grid, and, for example, the controller could be designed to help achieve target prices and / or availability of renewable energy on the external grid, regardless of the price / availability of non-renewable energy, for example, by increasing energy storage in energy production and storage systems when renewable energy production is high / electricity demand is low, and / or supplying renewable energy to the grid when renewable energy production is low / grid electricity demand is high. In this way, decisions about how to power electrolysis devices or how to charge energy storage devices (e.g., batteries) can be based on environmental factors (e.g., environmental "costs") as well as financial factors. If locally available renewable energy from renewable sources is insufficient, the power grid can be used in addition to that energy, or if locally available renewable energy is unavailable, the power grid can be used as the sole energy source.

[0009] The controller may be provided as part of a power switching system that receives electrical energy from various sources and supplies it to various electricity consumers. Sources may include power input connections from renewable energy sources, grid connections, and energy storage devices. Consumers may include electrolysis units, grid connections, and energy storage devices. The power switching system may also supply electricity to other local consumers, such as industrial or agricultural consumers, who may also utilize other products from the system, such as fish farms or other aquaculture systems. The controller may receive data from renewable energy sources and / or from the grid connected to the grid connection. For example, the power input connection and grid connection may be configured to transmit both power and data simultaneously. This may also apply to other connections to the controller and / or the power switching system, such as connections to energy storage devices and / or electrolysis units.

[0010] A controller is typically a computer-implemented control system and may include suitable hardware and / or software elements. In some examples, the controller incorporates machine learning algorithms (e.g., artificial neural networks) to process data received, such as (i), and determine how to control the energy production and storage system for one or more of (ii) and / or (iii), or other control processes. The controller may be configured (e.g., using machine learning algorithms) to track and predict (e.g., regarding one or more of the following) trends: actual or potential energy production from renewable energy sources, energy reserves in energy storage devices, balancing demand from the external grid, and / or the impact of the energy production and storage system operating as a balancing service provider on the grid. The controller may additionally or alternatively be configured to track external events (e.g., weather patterns) and take this into account when controlling the system. The controller may also be configured to identify patterns and utilize the identified patterns to control the system to optimize energy efficiency and / or optimize the production and use of renewable energy sources, whether for local consumption or external transmission to the grid. System control may include considering predictions of future trends when deciding to increase or decrease one or more of the following: the energy stored in the energy storage device, the energy use of the electrolyzer, the power drawn from or supplied to the external grid. Therefore, a controller implemented using a machine learning system can effectively predict and prepare for future events.

[0011] Power grid systems face challenges in balancing supply and demand fluctuations. To ensure consistent balance, reserve capacity is necessary. Different regions utilize different types of reserves based on the characteristics of the power system. Commonly used reserves include primary reserves, secondary reserves, tertiary reserves, and fast reserves. These reserves have different purposes, response times, and characteristics.

[0012] Frequency stability of a power system typically depends on the rotating mass / rotational energy / rotational inertia of the synchronous motors connected to the grid. The majority of the rotating mass is present in hydroelectric and thermal power plants (e.g., fossil fuel power plants), with a smaller portion present on the consumer side. The energy production and storage system of the first aspect advantageously contributes to frequency stability without including the type of rotating mass commonly found in synchronous motors. In some embodiments, renewable energy sources may also not include any rotating mass that contributes to grid stability. For example, there may be no generator with synchronous connection. In exemplary embodiments, the energy production and storage system of the first aspect does not include any form of thermal power plant; for example, it may not have any form of steam turbine and / or gas turbine. Omitting such a power plant also avoids the environmental impact of the energy production and storage system. Since this advantage can be extended by avoiding or minimizing the use of gas-phase combustion (even if this can use “green” hydrogen), in some examples, the energy production and storage system does not include any gas-phase combustion of hydrogen, or alternatively, there is no gas-phase combustion of any fuel. Therefore, hydrogen consumption in the energy production and storage system of the first aspect can be limited to non-gas-phase combustion and may include, for example, fuel cells and / or catalytic combustors.

[0013] Because no generators are in use, or generators are not synchronized with the grid, renewable energy sources such as solar and wind power do not contribute to stability through rotational mass. Therefore, the need for frequency balancing becomes greater under conditions of low load and low power generation, combined with a high proportion of renewable energy input into the grid.

[0014] Instantaneous response to changes / interruptions in power generation or consumption is achieved by converting the rotating mass (rotational energy) in the power system into electrical energy. Accordingly, the frequency will change, activating the primary reserve, which is typically divided into normal operation reserve (FCR-N) and disturbance reserve (FCR-D).

[0015] The secondary standby (automatic frequency restoration reserve, aFRR, sometimes also called load frequency control) is activated to bring the frequency back to 50.00 Hz, thereby releasing the activated primary standby to make it available for handling new faults and imbalances.

[0016] After the secondary reserve restores the frequency to the normal range, the tertiary reserve is activated to maintain system balance until the energy market reaches a new equilibrium. In addition to this frequency regulation, the tertiary reserve is also used to manage regional congestion and unbalanced flows.

[0017] Fast Frequency Reserves (FFR) are activated very quickly to prevent the frequency from dropping below 49.0 Hz in the event of a major power system fault or disturbance. The FFR is activated in approximately one second when the system frequency drops below a certain level. Different activation frequencies are possible, typically ranging from 49.5 Hz to 49.7 Hz. When a lower activation frequency is selected, the response must be delivered more quickly to achieve the desired effect.

[0018] The system in the first aspect can be configured to operate as a secondary standby (i.e., aFRR) or as a fast frequency standby (FFR). It should be understood that the switching required to release power from energy storage devices (such as batteries) can be completed rapidly within the time frame required by the FFR. Similarly, increasing the response time of the grid load by operating an electrolytic device can be quick because it can be kept in standby mode, thus enabling rapid startup.

[0019] An input power connection is used to receive electricity from renewable energy sources, which can be provided as alternating current (AC) or direct current (DC). The input power connection can also be part of a grid connection, for example, for receiving electrical energy from the grid. In this case, there may also be an output power interface as another part of the grid connection, or the input power connection can be implemented as a combined input / output interface. The optimal implementation can be selected based on the output power from the renewable energy source, for example, whether the output is AC or DC, and whether the voltage is similar to the grid voltage. The energy production and storage system may include an AC / DC converter, for example, to convert alternating current (AC) from renewable energy sources and provide it as direct current (DC) to an energy storage device or electrolysis device. The energy production and storage system may include renewable energy sources (or multiple renewable energy sources), which can advantageously be provided by local renewable energy production facilities. Using local energy sources improves efficiency.

[0020] For example, renewable energy can include one or more of solar, wind, hydropower, tidal, and / or wave energy.

[0021] Renewable energy sources can supply energy to the electrolysis unit directly or indirectly, for example, through grid-connected components and / or through energy storage devices. In some examples, the energy storage device can serve as the main power source for the electrolysis unit, while electrical energy from external sources is supplied through the energy storage device. Therefore, renewable energy can be used to charge the energy storage device, and the power used for the electrolysis unit can be obtained from the energy storage device. If energy input from the grid is required, the grid connection can be made via an AC / DC converter and charger to charge the energy storage device. The energy storage device can then power the electrolyzer via a DC / DC converter. Advantageously, supplying power indirectly through the energy storage device allows the use of existing AC / DC and / or DC / DC conversion systems within the system. Energy stored in the energy storage device can also be redirected to the grid. Direct current can be supplied directly from the energy storage device to the electrolysis unit via a control unit, which has the advantage of avoiding the need to integrate a rectifier into the electrolysis system.

[0022] The energy storage device must be able to provide peak power at least equivalent to the power required to operate the electrolysis unit, based on its storage capacity and discharge rate. Therefore, the energy storage device should be able to discharge to the grid at a level equal to or higher than the power drawn by the electrolysis unit (e.g., for balancing) for at least a short period (e.g., at least 5 minutes, at least 10 minutes, or at least 15 minutes). Advantageously, the energy storage device can have a sufficiently large capacity to power the electrolysis unit, for example, to assist in maintaining continuous power supply during a switch from renewable energy to the grid, or to allow the energy storage device to serve as an independent power source for the electrolysis unit. This facilitates the use of stored renewable energy for “green” hydrogen production when renewable energy production is unavailable (e.g., due to weather conditions). This can involve the full capacity of the energy storage device being able to power the electrolysis unit for a minimum period (e.g., 5 minutes, 15 minutes, at least one hour, or at least two hours, or in some cases at least five hours). This allows the energy storage device to be used to smooth variable electricity production from renewable energy sources by storing electricity (when renewable energy provides more power than the electrolysis unit requires) and discharging it (when renewable energy provides less power than the electrolysis unit requires).

[0023] Energy storage devices can also be used to reduce the cost of powering electrolysis production, for example, by storing energy from the grid and / or renewable energy sources when electricity prices are low, and drawing power from the energy storage device when grid-supplied electricity prices are high.

[0024] For example, an electrolysis unit may require 1 MW or higher, such as 2 MW or higher, optionally 15 MW or higher. Therefore, it can be a relatively large unit. Electrolysis units can be supplied by multiple units connected in parallel, such as multiple 5 MW units, which together require a higher combined power input. In some examples, electrolysis units may require up to 100 MW, and in some cases even higher. As mentioned above, energy storage devices can have storage capacity that allows for power supply to the electrolysis unit for at least 5 minutes, 15 minutes, at least 30 minutes, one hour or more, or several hours. Therefore, for example, in the case of an electrolysis unit with a power supply requirement of 1 MW or 50 MW, the energy storage device can have a total storage capacity of 2 MWh or 100 MWh or higher, allowing the electrolysis unit to operate for two hours. Energy storage devices are typically capable of discharging at approximately half their storage capacity; for example, at peak discharge rates, it may take two hours to fully discharge.

[0025] In addition to overall storage capacity requirements, energy storage devices can achieve high discharge rates as described above, for example, at least one-tenth, one-quarter, or one-half of the power demand of the electrolysis device, or in some cases, even higher.

[0026] An energy storage device may include one or more batteries, for example, using lithium-based chemicals such as lithium ions or any other chemicals that reflect desired characteristics such as charging and discharging. An energy storage device may be configured with multiple batteries or battery cells connected in series and / or in parallel as needed to provide the necessary voltage and power output.

[0027] Electrical energy storage devices can be battery energy storage systems, which may include batteries, control electronics, power conversion systems, and / or interface devices. Such interface devices are designed to provide protection for the interface system. Batteries store electrical energy through an electrochemical process that converts electrical energy into chemical energy and converts it back into electrical energy when needed. The electrical energy used in batteries is direct current (DC) rather than alternating current (AC). Depending on the application and its surrounding environment, different chemical substances may be used, including nickel, lithium, vanadium, graphite, magnesium, cobalt, silicon, cadmium, carbon black, lead, polyvinylidene fluoride (PVDF), and others. Significant efforts have been invested in battery technology development, including the search for / development of alternative sustainable chemical substances and the necessary materials.

[0028] The chemical energy stored in the batteries of an energy storage device can be converted into alternating current via a DC / DC transformer or a DC / AC converter. High-capacity or high-energy batteries are designed to store and deliver large amounts of energy and are commonly used in consumer electronics and electric vehicles. Currently, a typical single-cell battery has a voltage of 3.2VDC and a maximum continuous charge / discharge rate of 1C (meaning a fully charged battery with a rated capacity of 1Ah should provide 1Ah of energy for one hour). Batteries consist of cells that are typically connected in series, but can also be connected in parallel depending on the required final voltage and current. Typical battery module / pile voltages can range from 500VDC to 1500VDC.

[0029] Energy storage in batteries can be configured to meet various industrial or grid standards / requirements and can include DC / DC to DC / AC interfaces ranging from 400VAC to 33 / 132kV using transformers. The available energy storage capacity in a battery is typically higher than its power supply rate. For example, a 2.7MWh battery can have an output capacity of 1.5MW. This can be paired, for example, with an electrolysis unit rated at 3.2MW, and typically uses a power input lower than its rated power (e.g., 2MW).

[0030] Electrolysis units can be powered directly by renewable energy sources or the power grid, which can also provide renewable energy through energy storage devices (such as batteries). Electrolysis unit suppliers provide complete systems, including all necessary subsystems to ensure safe and reliable electrolysis operation throughout the entire process. These typically include a water treatment system to ensure the water used is suitable; a cooling system to ensure the maximum permissible battery stack temperature is not exceeded; a control system to monitor performance and report any issues requiring attention; and a power supply system to ensure sufficient and correct power is provided. Since electrolysis uses direct current (DC), the power supply system assumes power is drawn from the grid and therefore uses one or more rectifiers to convert alternating current (AC) to DC. Introducing energy storage devices (such as batteries) simplifies the electrolysis unit when battery power is already DC. This brings the advantage of indirectly powering the electrolysis unit using energy storage devices.

[0031] Renewable energy sources can be equipped with an average energy production capacity similar to, or even higher than, the power requirements of the electrolysis unit, so that the peak power generation capacity of the renewable energy source will exceed the power requirements of the electrolysis unit. For example, using wind power as a renewable energy source, although its average power generation capacity can be 2MW or 50MW to match the power supply requirements of the electrolysis unit (2MW or 50MW), its rated power generation capacity may be twice that value, and the peak power generation capacity may be even higher. The capacity of renewable energy sources can also be lower than the requirements of the electrolysis unit. In this case, the power input connection system must have the capacity to input the required additional capacity from the grid to power the electrolysis unit. Because the energy production and storage system includes energy storage devices, excess power production is not wasted, and energy is not wasted if the electrolysis unit does not need to operate or must be shut down for any reason (e.g., maintenance).

[0032] The grid connection is configured for bidirectional connection to an external power grid and advantageously capable of receiving and supplying power from the external grid at a suitably high rate, thereby providing at least 100% of the electrolysis unit's power requirements, or extracting an equivalent amount of power from an energy storage device. The grid connection can be, for example, a three-phase configuration, which is further adapted to connect to the electrolysis unit, the energy storage device, and optional renewable energy sources. These connections can take the forms known in the art.

[0033] The controller can receive information and control the current flowing into and out of the power grid using conventional methods. This can include information about electricity costs, which can be used to improve efficiency by referencing market forces that influence supply and demand, such as optimizing the use of energy storage devices from a cost perspective and / or optimizing hydrogen production. The controller can include independent hardware / software modules for performing different functions, and / or it can be distributed across multiple processors or sub-controllers in different parts of the system. For example, there could be an energy storage management system at the energy storage device, and / or a local control system for renewable energy.

[0034] Electrolysis units are used to electrolyze water to produce hydrogen, oxygen, and heat, all of which can be captured for storage and / or use. Hydrogen can be stored for later use. The hydrogen produced by the electrolysis unit is a commercially available product that can be used locally or remotely as fuel / energy after being transported to other systems. Because it can be stored under pressure in an energy production and storage system, the system can include hydrogen storage devices, such as storage tanks. Hydrogen production and / or storage can be carried out according to parameters (i.e., temperature, pressure) configured for subsequent transportation and / or use as fuel. For example, hydrogen can be output from the electrolysis unit at 5 to 90°C and 1 to 5 MPa and stored at ambient temperatures to 80°C and 1 to 90 MPa. The energy production and storage system can include a compressor for compressing the hydrogen before storage. The generated hydrogen can also be stored via solid-state diffusion using metal oxides, or as liquid hydrogen. Alternatively, it can be converted and stored in a carrier, such as ammonia or a liquid organic hydrogen carrier (LOHC), which can absorb or release hydrogen through chemical reactions.

[0035] To utilize hydrogen locally, for example, to further improve the efficiency of local energy systems, energy production and storage systems may include fuel cells and / or catalytic burners to utilize hydrogen to meet local electricity and / or heating needs. As mentioned above, preferably, the energy production and storage system does not include any gas-phase combustion of hydrogen. It is also possible that no type of gas-phase combustion exists.

[0036] Hydrogen (preferably green hydrogen produced by electrolysis powered by renewable energy) is particularly suitable as an energy carrier for thermal / heating applications due to its high gravimetric energy density and reactivity. Another way to utilize hydrogen for energy storage is to include a system that includes a heater configured to generate heat from hydrogen through, for example, catalytic combustion, and store the heat in a thermal storage device, such as a geothermal well.

[0037] In hydrogen electrolysis, for every 1 kg of hydrogen produced, 8 kg of oxygen is generated. The oxygen accumulated during electrolysis can be stored and / or used on-site, for example, in aquaculture facilities on land or at sea, or for other purposes. Therefore, the system may include oxygen storage devices (e.g., tanks), and / or oxygen outlets for delivering oxygen to consumers. Compared to applications such as medical use, the purity requirements for oxygen in aquaculture are relatively low, which avoids the need for additional purification treatment of the oxygen produced by the electrolysis unit, and / or allows for the use of less complex or more energy-efficient electrolysis units. The energy production and storage system may include a dryer for removing moisture / humidity from the oxygen, and / or a compressor for compressing the oxygen before storage.

[0038] Another use of the oxygen accumulated during electrolysis can be for oxy-fuel combustion to simplify carbon capture when burning fossil fuels. Therefore, energy production and storage systems can include oxy-fuel burners that receive oxygen directly or indirectly from the electrolysis unit. In this way, energy production and storage systems can be integrated or connected to industrial processes that use or require oxy-fuel burners, or the oxygen produced by the electrolysis unit can be delivered to the oxy-fuel combustion site. While gas-phase combustion has some disadvantages, these disadvantages can be mitigated by using oxy-fuel consumption. Therefore, energy production and storage systems can effectively avoid the combustion of hydrogen fuel gas while using oxygen for oxy-fuel combustion to reduce the adverse effects of industrial processes that rely on combustion as a necessary component. In some examples, energy production and storage systems may not include gas-phase combustion in addition to oxy-fuel combustion. Oxy-fuel combustion provides oxygen or a mixture of oxygen and recirculated flue gas to the combustion process, rather than air. This avoids large amounts of nitrogen, and the resulting combustion can be more efficient and / or produce fewer pollutants. In oxy-fuel combustion, processes associated with large amounts of nitrogen in the air are avoided because air is primarily replaced by oxygen. The resulting combustion products can contain up to approximately 90% CO2 (dry basis). Flue gas impurities (mainly O2, N2, and Ar) can be removed by reducing the flue gas (at moderate pressure) to a temperature at which CO2 condenses but the impurities do not.

[0039] Oxygen fuel combustion can be used for solid fuels (such as coal, petroleum coke, and biomass), as well as liquid and gaseous fuels.

[0040] The heat generated by electrolysis (which may be 20-30% of the energy input to the electrolysis unit) can be considered waste heat in some cases. However, in this system, it is considered a beneficial product of the electrolysis unit. This heat can be captured and stored (e.g., in geothermal wells / thermal batteries) or used on-site for district heating and / or industrial or agricultural needs, such as heating water for fish farming or other aquaculture systems. The electrolysis unit can generate heat at a temperature of approximately 40-80°C, for example in the form of a heated fluid (such as hot water), which can be a heated fluid flowing through the electrolysis unit (i.e., coolant) or a heated fluid exchanging heat with the coolant circuit of the electrolysis unit. The heated fluid can be used directly at the temperature discharged from the electrolysis unit, or stored at that temperature, or it can be heated / cooled to obtain a specific temperature required for a particular application. Hydrogen from the electrolysis unit can be used as fuel to increase the temperature of the heated fluid, for example, through a catalytic burner. As mentioned above, in some embodiments, there is no gas-phase combustion of hydrogen. Heat can be stored in geothermal wells / thermal batteries or other types of thermal storage devices, enabling energy production and storage systems to store thermal energy as well as electrical energy, and also to store hydrogen as an energy carrier. For example, heat can be stored in phase change materials, geothermal storage devices, or sand batteries.

[0041] For example, in energy production and storage systems with more than one heat consumer, the controller can manage the heat distribution from the electrolysis unit. Alternatively, a separate heat distribution control system can be provided.

[0042] As mentioned above, since aquaculture can be a consumer of both oxygen and heat generated by the electrolysis unit, it exhibits a specific synergistic effect with aquaculture (e.g., fish farming). Therefore, the present invention extends to combined aquaculture and energy production facilities, which include the energy production and storage systems discussed above and aquaculture facilities, such as aquaculture ponds for fish farming and / or for cultivating aquatic plants or algae. In the case of such combined aquaculture and energy production facilities, the controller can also control the aquaculture facilities, for example, by utilizing heat and oxygen from the electrolysis unit to monitor and control water temperature and / or water oxygen levels.

[0043] From a second aspect, the present invention provides a method for controlling energy production and storage using the energy production and storage system discussed above with respect to the first aspect, the method comprising: (i) Receive information relating to: actual or potential energy production from renewable energy sources, energy reserves in energy storage devices, and the balance demand of the external power grid; (ii) Utilizing energy from renewable energy sources to power the electrolysis unit and / or storing it in an energy storage device; and (iii) Based on the received information, the energy production and storage system is operated as a balancing service provider in either of the following ways: drawing power from the external grid to supply the electrolysis unit, or supplying power from the energy storage unit to the external grid, thereby acting as a switch to assist in balancing the external grid.

[0044] These steps can be performed at a controller, which can be configured as described above. The method may include receiving electricity from renewable energy sources at an electrical input connection. The method may include using a grid connection for bidirectional connection to receive and supply electricity to an external grid, for example, allowing the output of surplus energy and / or "supplementary" electricity when the electricity generated by renewable energy is insufficient to meet local demand. The method may include using renewable energy sources (only) from an external grid, for example, to ensure that the method is a method for controlling a renewable energy production and storage system to produce byproducts such as green hydrogen. Various features of the energy production and storage system may be described above in conjunction with optional features associated with the first aspect.

[0045] Some exemplary embodiments will now be described by way of example only and with reference to the accompanying drawings, wherein: Figure 1It is a schematic diagram of an energy production and storage system; and Figure 2 Variations of energy production and storage systems are shown.

[0046] like Figure 1 As shown, an energy production and storage system is provided for receiving electrical energy from one or more renewable energy sources 2 (such as wind, solar, hydro, wave, tidal, or others) and bidirectionally connecting to a power grid 4 (e.g., a national grid 4). A power switching system 6 with a controller 8 is used to control the flow of electricity. The renewable energy source is provided via an electrical input connection. The power grid 4 is connected via a grid connection 12. The power switching system 6 can also receive or supply electricity to an energy storage device 14, which is typically a rechargeable battery (e.g., a lithium-ion battery). It is understood that both the power grid 4 and the energy storage device 14 can act as a source or consumer of electricity. For example, the energy production and storage system may include a DC / DC converter or an AC / DC converter to convert AC current from the renewable energy source 2 into DC current and supply it to the energy storage device 14.

[0047] Electrolysis unit 16 electrolyzes water to produce oxygen (O2), hydrogen (H2), and heat. The electrolysis unit receives power via a power switching system 6, and a controller 8 determines whether the power is derived from the power grid 4, renewable energy source 2, or energy storage device 14. When power is derived from the power grid 4, renewable energy is preferred. Water can be sourced from rivers or lakes and appropriately filtered and purified. Alternatively, municipal water sources can be used. If necessary, the electrolysis unit may include additional water treatment. Hydrogen from electrolysis unit 16 can be delivered to hydrogen storage device 18, such as a storage tank. This hydrogen can be stored for subsequent use as fuel, either locally or after subsequent transport to other systems. The oxygen produced by the electrolysis unit can be compressed and prepared for output elsewhere, or stored and / or used locally, for example, by delivery to aquaculture facility 20. Advantageously, aquaculture and other alternative processes have relatively low oxygen purity requirements, which are well matched to the purity of the oxygen produced by electrolysis.

[0048] One approach to utilizing hydrogen locally (e.g., to further improve the efficiency of a local energy system) is to incorporate fuel cells and / or catalytic burners into energy production and storage systems to utilize hydrogen to meet local electricity and / or heating needs. In this example, there is no gas-phase combustion of hydrogen, nor any other type of gas-phase combustion.

[0049] The heat from the electrolysis unit 16 (up to 20-30% of the electrical energy input to the electrolysis unit 16) can be used locally for district heating 22 and / or to meet industrial or agricultural needs, such as heating the water for fish farming in aquaculture facility 20. Alternatively or additionally, the heat can be captured and stored in a thermal storage device 24, such as a geothermal well / thermal battery.

[0050] The controller 8 and the power switching system communicate with the power input connection 10, the electrolysis unit 16, the energy storage unit 14, and the grid connection 12. The controller 8 can receive information from the grid 4 (i.e., from the operator of the grid 4), renewable energy sources (e.g., from their control / monitoring systems), and the energy storage unit 14 via these connections. Therefore, the controller 8 can receive information regarding the actual or potential energy production of the renewable energy source 2, the energy stored in the energy storage unit 14, the power demand of the electrolysis unit (including its subsystems), and the balancing demand of the external grid 4. The controller 8 can also receive information about the electricity market in the external grid 4, such as variable costs / prices as a reflection of supply and demand.

[0051] This means that, in addition to controlling the energy supplied to the electrolysis unit 16 and the local distribution of electricity from the renewable energy source 2, the controller 8 can also operate the energy production and storage system as a balancing service provider for the power grid 4. Therefore, the controller 8 can increase the grid load by drawing power from the grid to supply electricity to the electrolysis unit 16 and operating the energy production and storage system. Alternatively, the controller 8 can supply power to the grid from the energy storage unit 14, thereby reducing the grid load. The controller 8 can also turn the electrolysis unit 16 on / off, producing another switching effect even without supplying power to the power grid 4. Furthermore, the controller 8 can divert electricity from the renewable energy source 2 to the grid or use electricity from the grid to charge the energy storage unit 14. Therefore, the load on the power grid 4 exhibits easily controllable variations that can be used to help meet the balancing needs of external power grid 4 operators.

[0052] The storage capacity and discharge rate of the energy storage device 14 should preferably enable the electrolysis device 16 to operate for 5 minutes, 15 minutes, or 30 minutes, for example, to help maintain a continuous power supply when switching between renewable energy and grid power. In some embodiments, the capacity of the energy storage device 14 is sufficient to enable the electrolysis device 16 to operate for at least one hour or several hours, such as two hours or five hours. This allows the system to cope with gaps in the power production of renewable energy 2 without continuously drawing power from the grid 4. When the power provided by renewable energy 2 exceeds the needs of the electrolysis device 16, the controller 8 can operate the system to store power in the energy storage device 14. When the power provided by renewable energy 2 is less than the needs of the electrolysis device 16, it can also operate the system to release power from the energy storage device 14. For example, the electrolysis device 16 may require 1MW, 50MW, or up to 100MW of power, in which case the energy storage device 14 may have a capacity of 2MWh, 100MWh, or 200MWh or greater, enabling it to power the electrolysis device for two hours. Alternatively, the energy storage device 14 can have a smaller capacity so that it is primarily used for balancing purposes, such as using stored renewable energy, without a secondary function of powering the electrolysis device 16. In one exemplary embodiment, the energy storage device has a capacity of 2.7 MWh and a discharge rate of 1.5 MW, while the electrolysis device consumes 3.2 MW when operating at full power. This allows for a switching / balancing effect of -3.2 MW to +1.5 MW.

[0053] Renewable energy source 2 can be a combination of different energy sources, or it can be just one type of energy source, such as a wind turbine array or a solar panel area. Renewable energy source 2 can be equipped with an average energy production capacity similar to the power requirements of electrolysis unit 16, such that, over a given period of time, sufficient renewable energy is generated on average to operate electrolysis unit 16, thereby meeting the production requirements of hydrogen, heat, and oxygen. The energy storage device 14 and the ability to draw electricity from the grid 4 allow for fluctuations in renewable energy production. For example, for a wind power facility, the average generating capacity could be 100MW to match the 100MW power supply demand of electrolysis unit 16, but the rated generating capacity of renewable energy source 2 could be twice that, and the peak generating capacity could be even higher. Any excess renewable energy can be sold back to the grid. In some cases, average energy production can be lower than the power supply demand of electrolysis. Any energy shortfall can be supplemented from the grid 4, preferably from renewable energy sources on the grid 4.

[0054] In some cases, controller 8 can assess the relative pricing of renewable energy from grid 4 compared to non-renewable energy from grid 4, and the controller can be designed to help achieve target prices and / or availability of renewable energy on external grid 4, thereby maximizing the use / availability of renewable energy. In this way, decisions about how to power electrolysis unit 16 or how to charge energy storage unit 14 can be based on environmental factors (e.g., environmental “costs”) as well as financial factors.

[0055] Because aquaculture can be a consumer of the oxygen and heat generated by the electrolysis device, combining electrolysis with aquaculture (such as fish farming) has particular advantages. Figure 1 The system can also be viewed as a combined aquaculture and energy production facility, comprising the energy production and storage system discussed above, and an aquaculture facility 20. This facility can be a complete aquaculture farm, including one or more aquaculture ponds for fish farming and / or for cultivating aquatic plants or algae. Typically, suitable locations for terrestrial fish farming also have a water source for electrolysis and are suitable for installing renewable energy sources such as solar parks or wind farms. In the case of such a combined aquaculture and energy production facility, the controller 8 can also control the heat and oxygen distribution and electricity of the aquaculture facility.

[0056] In another example, such as Figure 2 As shown, oxygen from electrolysis unit 16 can be used (or stored and transported) on-site as oxygen fuel for oxy-fuel burner 26. Other parts of the system can be as described above regarding... Figure 1 As discussed. Alternatively (or additionally), it can be used for other aerobic processes and / or combinations of these processes (e.g., in a system having both an oxygen fuel burner 26 and an aquaculture facility 20). When oxygen fuel combustion is used, it is advantageous that no other gas-phase combustion occurs within the system, in particular, hydrogen from the electrolysis unit 16 can not be used as fuel for gas-phase combustion (e.g., it can be consumed by a fuel cell or catalytic burner).

Claims

1. An energy production and storage system, comprising: Power input connection for receiving electricity from renewable energy sources; An electrolysis device used to electrolyze water to produce oxygen, hydrogen, and heat; Electrical energy storage devices; The power grid connection is configured for bidirectional connection to receive power from and supply power to the external power grid. as well as The controller is connected to and communicates with the power input, the electrolysis device, the energy storage device, and the power grid, wherein the controller is configured to: (i) Receive information relating to: the actual or potential energy production from the renewable energy source, the energy stored in the energy storage device, and the balancing demand of the external power grid; (ii) Using energy from the renewable energy source to power the electrolysis device and / or storing it in the energy storage device; and (iii) Based on the received information, the energy production and storage system is operated as a balancing service provider in either of the following ways: drawing power from the external power grid to supply the electrolysis unit, or supplying power from the energy storage unit to the external power grid, thereby acting as a switch to assist in balancing the external power grid.

2. The energy production and storage system as described in claim 1, wherein, The controller is configured to: while drawing power from the external power grid to supply the electrolysis device, store the power from the external power grid in the energy storage device, thereby increasing the peak power drawn from the grid; And / or while supplying power from the energy storage device to the external grid, supplying power from the renewable energy storage device to the grid, thereby increasing the peak power supplied to the grid.

3. The energy production and storage system as described in claim 1 or 2, wherein, The controller is configured to track and predict trends, thereby predicting future events and preparing for them.

4. The energy production and storage system as described in claim 1, 2, or 3, wherein, The energy production and storage system includes a power switching system capable of receiving electrical energy from various power sources and supplying electrical energy to various electricity consumers. The controller is part of the power switching system. The power sources include a power input connection for electricity from the renewable energy source, the grid connection, and the energy storage device. The electricity consumers include the electrolysis device, the grid connection, and the energy storage device.

5. The energy production and storage system as described in any one of the preceding claims, wherein, The energy storage device has a storage capacity and discharge rate that enable it to provide peak power that is at least one-quarter of the power required to operate the electrolysis device.

6. The energy production and storage system as described in any one of the preceding claims, wherein, The energy storage device has a storage capacity and discharge rate that enable it to provide peak power at least equivalent to the power required to operate the electrolysis device, and the energy storage device is capable of supplying power to the electrolysis device for at least 5 minutes.

7. The energy production and storage system as described in any of the preceding claims, wherein, The total storage capacity of the energy storage device is at least 1 MWh, and the power supply required by the electrolysis device is at least 1 MW.

8. The energy production and storage system as described in any one of the preceding claims, wherein, The energy from the external power grid is a renewable energy source.

9. The energy production and storage system as described in any of the preceding claims, wherein, In step (ii), energy from the renewable energy source indirectly powers the electrolysis device through the energy storage device; and / or in step (iii), electrical energy from the external power grid indirectly powers the electrolysis device through the energy storage device.

10. The energy production and storage system as described in any of the preceding claims, wherein, Gas-phase combustion of hydrogen does not exist.

11. The energy production and storage system of claim 10, comprising consuming hydrogen to generate heat and / or electricity without gas-phase combustion, for example by using a fuel cell and / or a catalytic burner.

12. The energy production and storage system as claimed in any of the preceding claims, comprising a hydrogen storage device for storing hydrogen from the electrolysis unit.

13. The energy production and storage system as described in claim 12, wherein, Hydrogen production at the electrolysis unit and / or hydrogen storage at the hydrogen storage unit are carried out at an ambient temperature of -80°C and a pressure of 1 to 90 MPa.

14. The energy production and storage system as claimed in any of the preceding claims, comprising an oxygen storage device and / or an oxygen outlet for delivering oxygen to an oxygen consumer.

15. The energy production and storage system as described in any of the preceding claims, wherein, Heat from the electrolysis unit is collected and stored and / or used locally.

16. The energy production and storage system as described in claim 15, wherein, The controller is configured to control the distribution of heat from the electrolysis unit to one or more heat consumers, selected from district heating, industrial processes and / or agriculture, such as water heating for aquaculture.

17. The energy production and storage system as described in any of the preceding claims, wherein, The electrolysis device generates heat at a temperature of 40 to 80°C, and hydrogen from the electrolysis device is used as fuel to increase the temperature of the heated fluid.

18. The energy production and storage system as claimed in any of the preceding claims, comprising an oxy-fuel burner that receives oxygen from the electrolysis unit.

19. A combined aquaculture and energy production facility, comprising an energy production and storage system as described in any of the preceding claims and an aquaculture facility, wherein the aquaculture facility receives oxygen and heat from the electrolysis unit.

20. A method for controlling energy production and storage using an energy production and storage system as described in any of the preceding claims, the method comprising: (i) Receive information relating to: the actual or potential energy production from the renewable energy source, the energy stored in the energy storage device, and the balancing demand of the external power grid; (ii) Using energy from the renewable energy source to power the electrolysis device and / or storing it in the energy storage device; as well as (iii) Based on the received information, the energy production and storage system is operated as a balancing service provider in either of the following ways: drawing power from the external power grid to supply the electrolysis unit, or supplying power from the energy storage unit to the external power grid, thereby acting as a switch to assist in balancing the external power grid.

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