Hydropower plant and storage facility

Abstract

Hydropower plant (1) comprising a power generation unit (8) and a storage unit (4, 12) for energy in a storable form, wherein the power generation unit (8) in the hydropower plant (1) converts the kinetic energy of the water into electrical energy corresponding to the energy content of the continuously available quantity of water, taking into account an efficiency of the power generation unit (8), characterized in that the storage unit (12) is designed as a battery (12) which receives electrical energy generated in the power generation unit (8) during a charging phase and releases it from the battery (12) during a discharging phase, wherein the electrical power of the power generation unit (8) is less than the electrical power that the battery (12) is capable of delivering, and wherein the charging phase is longer than the discharging phase, wherein the charging phase is dimensioned to be long enoughthat the entire supply of kinetic energy is utilized in the power generation unit (8) and the release of electrical energy from the battery (12) for temporary demand-dependent feed-in at maximum power into a power grid (14) during the discharge phase, wherein the discharge phase is dimensioned to be long enough to free up storage capacity of the battery (12) for the renewed absorption of generated electrical energy.

Description

[0001] The invention relates to a hydropower plant comprising a power generation device and a storage device for energy in a storable form, wherein the power generation device in the hydropower plant converts the kinetic energy of the water into electrical energy, which corresponds to the energy content of the continuously available quantity of water, taking into account an efficiency of the power generation device.

[0002] Under the heading of electricity market flexibility, the aim is to achieve demand- and yield-oriented electricity production, which requires shifting the feed-in of electricity to times when electricity is needed, while storing excess electricity when it is not required. This oversupply results in negative or very low electricity prices. In recent years, therefore, the focus has shifted to preparing existing and new generation facilities for the open energy market and, in accordance with applicable legal requirements, making the supply of electricity more flexible based on demand and yield. This primarily means creating the technical prerequisites to be able to supply different amounts of electricity at different times.Specifically, this means not feeding energy into the grid during periods of low (or negative) electricity prices, and instead feeding in the maximum possible output and the amount of energy available at that time during periods of high electricity prices. Furthermore, feeding in electricity during periods of surplus will increasingly be prohibited and prevented by technical means in the interest of grid stability. In the hydropower sector, this problem is traditionally solved by dams or pumped-storage power plants. However, their construction is complex, time-consuming, and involves significant environmental impacts.

[0003] Document DE 10 2007 016 280 A1 addresses an energy storage technology, specifically an energy storage system designed for storing energy from renewable energy sources. The aim is to ensure reliable and efficient energy storage to compensate for fluctuations in the energy supply. The document explains how the system can contribute to maximizing the efficiency of energy sources such as wind and solar power by storing excess energy and releasing it when needed. Particular attention is paid to optimizing the storage technology to ensure a long service life and high performance.

[0004] Document DE 10 2007 016 281 A1 describes an energy storage system as part of a hybrid system specifically designed for renewable energy sources. However, at least one additional renewable energy source is required. The goal is to compensate for fluctuations in the energy supply and to ensure efficient and reliable energy storage. The system consists of numerous storage units with a modular design, allowing for easy scalability as needed. Each storage unit contains battery cells housed in special enclosures to ensure mechanical protection and thermal stability. An energy management system (EMS) continuously monitors the charge and discharge status of the batteries, ensuring efficient energy storage and release when required.

[0005] No solution is currently known for feeding electricity from hydropower plants into the grid at short notice in response to fluctuating demand. The object of the invention is therefore to offer a solution that addresses this issue and enables demand-driven feed-in of electricity from hydropower plants with minimal technical and organizational effort.

[0006] The problem is solved by a hydropower plant comprising a power generation unit and an energy storage unit. The power generation unit converts the kinetic energy of the water into electrical energy, which corresponds to the energy content of the continuously available water flow, taking into account the efficiency of the power generation unit. The power generation unit achieves a power output that is at least equal to the energy content of the average continuous supply of kinetic energy, again considering the efficiency of the power generation unit. If the power generation output is too low, the available hydropower cannot be fully utilized.

[0007] According to the invention, the storage device is designed as a battery that absorbs electrical energy and releases it as needed, e.g., a lithium battery or a lead-acid battery. The electrical energy generated during a charging phase in the power generation unit, whose installed capacity essentially corresponds to the power generation capacity, is stored at least partially, but predominantly, in the battery. Preferably, the generated electrical energy is stored completely in the battery. An exception is the power required for the operation of the plant or the business premises, which is consumed directly.

[0008] During a discharge phase, electrical energy is supplied either from the battery alone or, preferably, simultaneously from the battery and the hydropower plant or its power generation unit, whereby the feed-in power can be measured independently of the electrical output of the power generation unit. The feed-in power can be several times the installed capacity of the power generation unit.

[0009] Within the scope of the invention, storage and release from the battery for the purpose of grid feed-in are considered, and the typically present internal consumption is disregarded for the sake of simplicity. The total installed electrical power corresponds to the maximum electrical power that can be fed into the grid. The total electrical power is matched to the amount of kinetic energy in such a way that essentially uninterrupted, continuous operation of the power generation device occurs throughout the charging phase. During the charging phase, the storage of surplus electricity from the public grid can also be utilized at times of negative or slightly positive electricity prices.

[0010] The electricity generated is primarily fed into the public grid, but also supplied to consumers in the vicinity of the plant, particularly to the business to which the plant belongs. The advantages of the invention are realized when feeding electricity into the grid because, on the one hand, there are economic, grid-related, and temporal constraints, especially if revenue is to be generated through electricity sales, and on the other hand, there is a high absorption capacity, provided the grid is capable of accepting the electricity during the period corresponding to the discharge phase. Furthermore, high revenues can be generated during periods of high electricity costs, which coincide with the discharge phase according to the invention.

[0011] It is preferably intended that the charging and discharging phases fall within a single day, with the charging phase essentially encompassing the entire day and the discharging phase essentially encompassing the part of the day in which there is a demand for electricity from consumers, but especially in the power grid. The charging phase can also be shorter if there is already an over-provision of capacity, for example, by doubling the capacity of the power generation facility (single over-provision), in which case the charging phase is reduced to 12 hours. During the times outside the discharging phase, feed-in will be technically prevented because the power grid is unable to absorb it due to oversupply, and no further feed-in is permitted in the interest of grid stability. Furthermore, it is not economically viable and does not generate any operational profit.

[0012] It has proven advantageous to have a charging phase long enough to convert all available kinetic energy into electricity. The power generation unit therefore typically runs for 24 hours (provided there is no overcapacity), all day long, continuously generating electricity. The electricity is stored and, optionally, fed directly into the grid at certain times. Conversely, the discharging phase is long enough to free up a storage capacity in the battery, hereinafter also referred to as battery capacity, for the next generation of electricity.

[0013] Advantageously, the battery capacity is dimensioned to be at least large enough to fully absorb the electrical energy generated during the charging phase, preferably for at least 12 hours, but also up to 24 hours, when electrical energy is supplied exclusively from the battery. Alternatively, the battery's storage capacity is dimensioned to be at least large enough to fully absorb the electrical energy generated in the power generation unit during the time difference between the charging and discharging phases. This applies in the case where electrical energy is supplied from both the power generation unit and the battery simultaneously, e.g., to the power grid.

[0014] According to the invention, the battery's output power is dimensioned to be at least high enough to fully release the electrical energy stored during the charging phase. This release must occur within a few hours of the day. Particular attention must be paid to the shortest possible discharge phase, especially if, for example, it is to be optimized for a limited period with the highest compensation for economic reasons. The output power must be significantly higher. This is reflected in a diagram showing the daily fluctuations as a "double peak" in the morning and evening.

[0015] In an advantageous design, the battery also absorbs electricity from other fluctuating energy sources (e.g., solar, bioenergy, or wind power) during the charging phase and releases it again at a later time during the discharge phase. Alternatively or additionally, it is also possible for the battery to absorb electricity from the public grid, especially when prices are negative or very low, store it temporarily, and feed it back into the grid at a later time. This can relieve the strain on the electricity grid and generate additional economic benefits.

[0016] The hydroelectric power plant includes a power generation facility and a storage facility for energy in a storable form, which can absorb at least part of the daily production of electricity.

[0017] According to the invention, the conversion capacity of the power generation device corresponds to the energy content of the continuously available amount of kinetic energy from hydropower. The storage device is designed as a battery, the storage capacity of which is dimensioned such that electrical energy generated in the power generation device during a charging phase is stored in the battery and released from the battery during at least one discharge phase, or alternatively, simultaneously from the battery and the power generation device. The electrical power of the power generation device is lower than the electrical power that the battery is capable of delivering, hereinafter referred to as the output power. The electrical power of the power generation device is, for example, 10% of the battery's power.This means that the battery can deliver 10 times more power than the installed power generation unit of the hydroelectric plant is capable of delivering.

[0018] The charging phase is, for example, 3 to 12 times longer, preferably 6 to 12 times longer (reserves can be built in here), than the discharging phase. Conversely, this means that the entire 24-hour electricity generation can be delivered within a few hours at a correspondingly higher output when there is sufficient demand and a correspondingly higher feed-in tariff. Instead of over-engineering, i.e., exceeding the output of the power generation unit, this can be achieved with even higher output at a lower cost using the battery.

[0019] During the extended charging phase, the electrical energy generated in the power generation unit, whose installed capacity essentially corresponds to its power generation capacity, is stored in the battery. Any self-consumption within the hydropower plant and its operational environment is to be disregarded within the scope of the present invention. Instead, the focus is on feeding electrical energy into the power grid to achieve so-called flexibility. During a shorter discharge phase, electrical energy is released from the battery or, alternatively, simultaneously with the power generation unit.

[0020] The discharge and charging phases according to the invention occur within one day (or longer in some cases), with the charging phase being long enough to allow the entire available hydropower to be used in the power generation unit and lasting at most the entire day. During the discharge phase, electrical energy is released from the battery for temporary, demand-driven feed-in at maximum power into a power grid, with the discharge phase being long enough to free up battery storage capacity for the subsequent storage of generated electrical energy.

[0021] The feed-in power can be measured independently of the power generation unit's output. Simply put, the power generation unit operates according to the operator's preference and in line with their operational concept. Feed-in is solely demand- and yield-oriented, taking into account the current availability of electricity.

[0022] Preferably, at least the battery or the battery and the power generation device are connected to a control device that controls the output, in particular the feed-in to a power grid, of electrical energy during the discharge phase depending on the electrical energy demand in the power grid.

[0023] The power generation facility comprises at least one hydroelectric plant. Its inevitably occurring daily fluctuation in energy production can also be shifted accordingly to periods of increased demand. However, the comparatively lower overall output in a facility that, for example, has roof surfaces covered with PV modules, is not a significant factor in determining the battery capacity for the solution according to the invention.

[0024] Alternatively, the battery can be installed separately from the power generation unit. For example, the battery could be located at a grid connection point to the next higher voltage level, such as 10 kV, 20 kV, or 110 kV. This has the advantage that the downstream medium-voltage level, e.g., 20 kV, only needs to transmit the relatively low continuous power output of the hydroelectric power plant, while the high power output from the battery is fed directly into the grid at the higher voltage level. This is essential if the maximum instantaneous power output exceeds the local grid capacity. Charging then takes place either via a separate line or, in a balancing manner, via the grid to which the power generation unit is connected.

[0025] Furthermore, at such a position, the battery can be very advantageously used in addition to supplying or receiving control power for the purpose of grid stabilization through positive or negative minute control power, thus achieving an additional effect completely separate from the flexibility according to the invention. Primary control power, secondary control power, minute reserve, positive control energy, negative control energy, and negative residual load (through withdrawal) can also be influenced in a manner advantageous to grid stability. The residual load is the portion of electricity consumption that is independent of the volatile energy sources wind and solar. It is therefore the remaining electricity demand that is still predominantly met by conventional sources. The invention offers a solution to change this.

[0026] It has also proven advantageous if the battery can provide emergency power, i.e., supply the consumers connected to the local power grid (e.g., in operation) in the event of a grid failure, effectively creating an island grid, and if it is capable of a black start. In this context, black start capability means that the system is able to start and stabilize an island grid without an external power supply. Specifically, this means: • Standalone start: The battery storage system can be activated and supply electrical energy without an existing grid connection. This is essential in situations where the power grid has completely failed (blackout). • Grid setup: The battery storage system can provide the necessary voltage and frequency to power other devices or systems, thus serving as the basis for rebuilding a local or larger power grid. • Flexibility and control: The storage system can gradually increase the power supply and synchronize it with other generators (e.g., emergency power generators or renewable energy sources) to ensure a stable grid.

[0027] This is particularly important in areas such as critical infrastructure or industrial plants, but also in agricultural operations, to ensure security of supply even after a network blackout.

[0028] The invention allows existing (and also new) systems to be equipped with a suitable battery instead of a high-capacity power generation unit, in order to enable a flexible and instantaneous power supply without having to maintain the power output of the power generation unit at such a high level.

[0029] Although the power generation facility is designed for continuous hydropower utilization, the feed-in of electricity is nevertheless solely based on demand and yield. Depending on the battery capacity, the feed-in time of the battery (and additionally the power generation facility) then decreases, for example, to 3 hours (8-fold expansion, 8 times the power compared to continuous operation) to approximately 12 hours (single expansion, twice the power compared to continuous operation).

[0030] With constant hydropower production, one or more hydropower plants continuously generate electricity, independent of electricity prices and demand, and use this energy to charge the battery. The electricity is then fed into the public grid from the battery as needed, based on demand and available power. If required, additional electricity can also be fed directly from the power generation plant during this time to further increase the output.

[0031] An alternative option is to adjust the loading phase over the course of the year.

[0032] If excess battery capacity is available due to lower hydropower supply, it can be used to store electrical energy from other sources, e.g., for excess PV power in the summer or for electricity from the grid during periods of surplus at negative or slightly positive prices.

[0033] The following example of interpretation, which is intended to illustrate the concept according to the invention in more detail, basically applies: The electrical energy is generated exclusively from hydropower at the plant and then either fed in directly or first stored in the battery storage and then fed into the public electricity grid according to demand and yield.

[0034] Design example: Existing system with an installed capacity of 500 kW el Daily electricity generation: 12,000 kWh / day Operating time of the power generation plant: 24 h / d Feed-in time of the power generation plant: 6 h / d (into the power grid) Charging time of power generation plant to battery: 18 h / d Battery charging quantity: 9,000 kWh / day Battery discharge time to the power grid: 6 h / d Battery discharge rate: 9,000 kWh / day Battery discharge power: 1.500 kW el

[0035] The invention is explained in more detail below with reference to the description of exemplary embodiments and their illustration in the accompanying drawings. The drawings show: Fig. 1: schematically a perspective view of an embodiment of a hydropower plant according to the invention as per the design example; Fig. 2: schematically a process flow for the operation of a hydropower plant according to the invention as shown in the design example.

[0036] Fig. Figure 1 schematically shows a perspective view of an embodiment of a hydropower plant 1 according to the design example. The requirement that electrical energy can only be fed into the power grid 14 during the discharge phase, i.e., during the part of the day when it is possible to feed electrical energy into the grid 14, is fulfilled according to the invention by storing electrical energy in a battery 12.

[0037] The kinetic energy of the hydropower 2 is transferred directly to the power generation unit 8, in particular the generator 8, which runs during a charging phase, preferably all day long. This allows the entire available kinetic energy to be utilized while simultaneously minimizing the power consumption of the power generation unit 8.

[0038] The control unit 6 monitors the discharge phase during which electrical energy may be fed into the power grid 14. As soon as this period begins, electrical energy is fed into the power grid 14 both from the battery 12 and additionally from the power generation unit 8, which will continue to be in operation.

[0039] During the remaining time, the charging phase, battery 12 is charged without any connection to the power grid 14 from either battery 12 or the power generation unit 8. All electrical energy generated in the power generation unit 8 is therefore stored in battery 12.

[0040] Fig. Figure 2 schematically shows a process flow for operating a hydropower plant 1 according to the design example. It is checked whether sufficient hydropower is available; if so, the power generating unit 8 goes into operation and generates electrical energy.

[0041] Depending on the time period during which the electricity is generated, a decision is made regarding its use. During the charging phase, all generated electricity is stored in battery 12. However, if it is determined that the discharge phase (i.e., no longer the charging phase) has begun or is underway, the generated electricity is fed directly from the power generation unit 8 into the power grid 14. Additionally, and most importantly, battery 12 is discharged, and the extracted electricity is also fed into the power grid 14. As a result, the amount of electricity fed into the grid during the discharge phase is significantly greater than the electrical power supplied by the power generation unit 8 alone, even if it were "overbuilt" in the conventional sense. Reference symbol list 1 hydroelectric power plant 2 Hydropower 6 Control unit 8 Power generating unit, generator 12 Storage device, battery 14 Power grid QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2007 016 280 A1

[0003] DE 10 2007 016 281 A1

[0004]

Claims

[1] Hydropower plant (1) comprising a power generating unit (8) and a storage unit (4, 12) for energy in a storable form, wherein the power generating unit (8) in the hydropower plant (1) converts the kinetic energy of the water into electrical energy corresponding to the energy content of the continuously available quantity of water, taking into account an efficiency of the power generating unit (8), characterized by, that the storage device (12) is designed as a battery (12) which receives electrical energy generated in the power generation device (8) during a charging phase and releases it from the battery (12) during a discharging phase, wherein the electrical power of the power generation device (8) is less than the electrical power that the battery (12) is capable of delivering, and wherein the charging phase is longer than the discharging phase, wherein the charging phase is dimensioned to be long enough to utilize the entire supply of kinetic energy in the power generation device (8) and the release of electrical energy from the battery (12) for temporary demand-dependent feed-in at maximum power into a power grid (14) during the discharging phase, wherein the discharging phase is dimensioned to be long enough to release a storage capacity of the battery (12) for the renewed absorption of generated electrical energy. [2] Hydropower plant according to claim 1, wherein the loading phase and the unloading phase are within one day. [3] Hydropower plant according to claim 1 or 2, wherein the battery (12) also receives electricity from other fluctuating energy sources and / or from the public grid during the charging phase and releases it again during the discharging phase. [4] Hydropower plant according to one of the preceding claims, wherein at least the battery (12) and the power generation unit (8) are connected to a control unit (6) which controls the output of electrical energy during the discharge phase depending on the electrical energy demand in a power grid (14). [5] Hydropower plant according to one of the preceding claims, wherein the storage capacity of the battery (12) is dimensioned to be at least large enough to fully absorb the electrical energy generated during the charging phase when electrical energy is supplied exclusively from the battery (12). [6] Hydroelectric power plant according to one of claims 1 to 4, wherein the storage capacity of the battery (12) is dimensioned to be at least so large that at least the difference between the electrical energy generated in the charging phase and the electrical energy generated in the discharging phase can be fully absorbed when electrical energy is simultaneously supplied from the power generation device (8) and the battery (12). [7] Hydroelectric power plant according to one of the preceding claims, wherein the electrical power that the battery (12) is able to deliver is dimensioned to be at least so large that the electrical energy stored during the charging phase can be completely released during the discharging phase. [8] Hydroelectric power plant according to one of the preceding claims, wherein the battery (12) is located separately from the power generating unit (8). [9] Hydroelectric power plant according to one of the preceding claims, wherein the battery (12) can also provide emergency power and is capable of black start.

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