CONTROL UNIT FOR AN ENERGY FEED UNIT, ENERGY FEED UNIT, ENERGY FEED SYSTEM AND GRID INFRASTRUCTURE

Description

TECHNICAL AREA

[0001] The present disclosure relates generally to the technical field of feeding electrical energy into an electrical supply network. In particular, the present disclosure relates to a control unit for an energy feed-in unit, an energy feed-in unit for feeding electrical energy into an electrical supply network, an energy feed-in system comprising a control unit, an energy feed-in unit and an energy generator, and a network infrastructure comprising an energy feed-in system and an external energy consumer connected to it via an electrical supply network. BACKGROUND

[0002] Private and public buildings are increasingly being equipped with a renewable energy source, such as a photovoltaic system. Such a system typically comprises numerous photovoltaic modules on the roof or facade of the building, an inverter to convert the direct current generated by the photovoltaic modules into alternating current, a battery to temporarily store generated but not immediately needed energy, a charge controller to charge the battery and prevent excessively high or low charging voltages, and a grid connection unit to feed the electrical energy generated by the photovoltaic modules into the public power grid.

[0003] When there is sufficient sunlight, the photovoltaic system generates electricity, which is fed into the home's electrical grid and used by the building's appliances (such as refrigerators, televisions, washing machines, etc.). If the electricity generated by the photovoltaic modules is insufficient to cover the building's own energy consumption, electricity is purchased from a grid operator. If the photovoltaic modules generate more electricity than needed, the battery is charged. Once the battery is fully charged, and the photovoltaic modules continue to generate more electricity than required, this excess electricity is fed into the public grid under the control of the energy feed-in unit. In such cases of surplus feed-in, the grid operator to whose network the photovoltaic system is connected typically bills the owner for the energy supplied. The owner of the photovoltaic system has a feed-in tariff agreement with the grid operator for this purpose.

[0004] The publication DE 10 2011 085 676 A1 concerns an energy feed-in unit for a building, which selectively controls a grid feed-in taking into account active and reactive power occurring at the feed-in point, the building's own demand and a permissible feed-in power.

[0005] Publication US 2018 / 287388 A1 concerns a technique for the controlled distribution of integrated power supplies for electrical loads.

[0006] Document US 2013 / 113413 A1 concerns a grid-connected solar battery charger for energy management of a house and a vehicle.

[0007] The expansion of renewable energy generation in homes and buildings is leading to an increasing number of connections to the electrical transmission and distribution networks operating in bidirectional mode. This results in the supply and receipt of electricity at numerous points within the transmission and distribution networks. A major challenge for network operators is ensuring grid stability, i.e., guaranteeing a stable and uninterrupted power supply. Grid stability can only be maintained if the amount of electricity fed into the grid at any given time equals the amount consumed. Maintaining grid stability is achieved through both a stable grid voltage and a consistent grid frequency. If electrical power consumption is lower than production, the grid frequency is higher. If consumption exceeds production, the grid frequency is lower. If the grid voltage or frequency fluctuates, the grid can become unstable.If the mains frequency falls outside its tolerance range, devices connected to the power grid can be damaged. In the worst case, the power supply will fail completely.

[0008] Network operators are responsible for security of supply and grid stability and procure measures to ensure grid stability, known as ancillary services, from other users of the electrical supply network. These ancillary services include reactive power, which enables a stable grid voltage, and the provision of balancing power, which guarantees a consistent grid frequency.

[0009] To ensure grid stability, it can be beneficial to feed electricity generated by a local energy producer, such as a photovoltaic system, into the electrical grid. However, it is up to the local energy producer, for example, the operator of the photovoltaic system, to decide whether to feed the electricity they generate into the public grid. Furthermore, the local energy producer typically has no information as to whether, at a given time, feeding their generated electricity into the grid is desired to ensure grid stability. In particular, there is no communication or direct exchange of information between the local energy producer and the grid operator or the external energy consumer. BRIEF SUMMARY

[0010] The present disclosure is based on the task of providing a control unit for an energy feed-in unit, an energy feed-in unit for feeding electrical energy into an electrical supply network, an energy feed-in system and a network infrastructure, which contribute to increased network stability of an electrical supply network.

[0011] This task is solved by the control unit according to claim 1.

[0012] According to a first aspect, a control unit for an energy feed-in unit for feeding electrical energy into an electrical supply network is provided, wherein the energy feed-in unit is electrically connected to the electrical supply network and an energy generator, and the control unit has a first communication interface which is set up to receive a first value from an external energy consumer which is connected to the energy feed-in unit via a communication network and a first data storage unit which is set up to store a second value, wherein the control unit is set up to compare the first value with the second value and, depending on the comparison result, to control the feed-in of electrical energy into the electrical supply network.

[0013] The electrical supply network, also commonly called the power grid, is an electrical network for the transmission and distribution of electrical energy. It includes lines such as overhead lines and underground cables, and associated facilities like switching stations and transformer substations. The energy generator can be any type of energy producer, particularly a producer of renewable energy, such as a photovoltaic system, a wind turbine, or a heat pump. The external energy consumer can be any type of energy user connected to the energy supply unit via the electrical supply network. Examples of external energy consumers include municipal utilities, power plant operators, grid operators, electricity traders, or nearby buildings or businesses.A large number of external energy consumers can also be connected to the energy feed-in unit via the electrical supply network.

[0014] The first data storage unit can be any type of data storage unit that allows data to be read and written. Cloud-based data storage is also conceivable. The first communication interface can be any type of communication interface, such as an internet, mobile network, LAN, or WLAN interface, that enables communication with an external energy consumer (e.g., a network operator). Accordingly, the communication network can be a data network (internet, 5G network, etc.) configured to enable communication via the respective first communication interface.Since the control unit can be installed in basement rooms, the first communication interface for a wireless connection to the Internet preferably operates according to the 3GPP Narrowband Internet of Things (NB-IoT) or Long Range Wide Area Network (LoRaWAN) standard.

[0015] The first value is preferably an electricity price, e.g., a price per kilowatt-hour (kWh), which is received from the external energy consumer via the first communication interface. The second value can also be an electricity price. It is important that the first and second values ​​are assigned the same unit so that they are comparable.

[0016] The control unit compares the first value with the second value. Specifically, the control unit determines whether the electricity price offered by the external energy consumer is acceptable and, based on the comparison result, decides whether the electrical energy generated by the energy producer is fed into the electrical grid. For example, if the received first value is higher than the stored second value, the offer from the external energy consumer is accepted. However, if the received first value is lower than or equal to the stored second value, the offer from the external energy consumer is not accepted.

[0017] Since the initial price is provided by the external energy consumer, this consumer can incentivize the energy producer to feed the generated energy into the electrical grid. For example, if additional energy needs to be fed into the grid to ensure grid stability, the external energy consumer can offer the energy producer a relatively high price above the initial price, increasing the likelihood that the producer will accept the offer and feed the generated energy into the grid. Consequently, the external energy consumer has an indirect means of influencing (via a higher offer) the demand for additional energy feed-in to ensure grid stability.

[0018] According to one embodiment, the energy input unit is connected to a battery configured to temporarily store energy generated by the power generator, and the control unit is configured to manage the feed-in of electrical energy into the electrical grid even when the battery is not fully charged. In this case, even if the electrical energy generated by the power generator could still be used to charge the battery, the generated electrical energy is fed into the electrical grid. The stability of the electrical grid takes precedence over the temporary storage of electrical energy in the battery. For this purpose, the control unit can be supplied with information regarding the battery's state of charge by the battery or a charge controller.In particular, it can be stipulated that electrical energy generated by the power generator is fed into the electrical grid until the battery reaches a predetermined minimum charge level. However, it is also possible for the electrical energy generated by the power generator to be fed into the electrical grid when the battery is completely discharged. Furthermore, the control unit can accept a relatively low initial value if the battery is already almost fully charged, i.e., has reached a predetermined minimum charge level. In this case, different initial values ​​are stored in the first data storage unit for different battery charge levels.

[0019] The energy feed-in unit can also be electrically connected to a consumer (for example, a refrigerator, a washing machine, a light, etc.). In this case, the control unit can be configured to manage the feed-in of electrical energy into the power grid even when the consumer can use the energy generated by the power generator. This means that, to increase the stability of the power grid, energy generated by the power generator is fed into the grid even when it could be used by the consumer. Thus, it is conceivable that consumers are prioritized, i.e.,Certain consumers in a house or building are still supplied with energy generated by the energy producer, but other consumers do not receive energy from the energy producer and this additional energy is fed into the electrical supply network.

[0020] The control unit may also include an authentication unit configured to verify whether the initial value originates from the external energy consumer. Since feeding electrical energy into the power grid can affect grid stability, it must be ensured that the control unit does not mistake falsified initial values ​​for genuine ones. For example, imagine that a large number of falsified initial values ​​with a high initial value are sent to a large number of control units, and that these control units, based on the high initial value, decide to feed electrical energy into the power grid simultaneously. In this case, there is a risk that the multiple grid injections will destabilize the power grid.

[0021] The control unit may also include a second data storage unit configured to store a certificate for authenticating the external energy consumer and / or an internet address for sending confirmation of the received initial value via the first communication interface. For example, it may be stipulated that an acceptance of an offer must be sent to a specific internet address so that the recipient can determine if a fraudulent offer has been accepted and react accordingly, or inform the authorities. The control unit can also use the certificate to verify that the received initial value actually originates from the specified external energy consumer. Such security measures ensure that a forged initial value is not considered valid by the energy producer, thereby further guaranteeing grid stability.Furthermore, the energy producer is protected from feeding the energy he has generated into the electrical supply network without being billed for it and receiving no money.

[0022] The second data storage unit can be a read-only storage device (read-only storage), and / or the data stored in the second data storage unit can be password-protected and / or encrypted. These security measures prevent, for example, the certificate or the internet address from being easily changed, which in turn reduces security against external manipulation and contributes to network stability. The second data storage unit can also be configured as a Trusted Platform Module (TPM). Furthermore, it is possible to authenticate the data exchanged via the first communication interface using a blockchain. In this case, both the control unit and the external energy consumer have access to a distributed ledger and its immutable transaction record, in which the initial value is stored.

[0023] The first communication interface can also be configured to receive initial values ​​from a multitude of external energy consumers via the communication network. This enables the energy producer to supply the electricity it generates to various external energy consumers. If, for example, the initial value is an electricity price, then an external energy consumer with a high energy demand at a given time to ensure grid stability can increase their likelihood of being awarded the contract to supply the electricity generated by the energy producer by sending a relatively high initial value to the first communication interface.

[0024] In the control unit, the first data storage unit can be configured to store a multitude of second values, each together with a battery charge level and / or a time value. The control unit can also be configured to control the feed-in of electrical energy into the electrical grid depending on the battery charge level and / or the time value. In this embodiment, the first data storage unit stores direct mappings between second values ​​and the battery charge level and / or time. This allows the energy producer to decide individually, depending on the battery charge level or a specific time, whether it makes sense to feed electrical energy into the electrical grid.For example, the energy producer can take into account that they typically have a high energy demand at a certain time, such as in the morning, and thus set the second value higher for that time. They will only agree to feed electrical energy into the grid if the first value is also higher. It is then up to the external energy consumer to decide how much they are willing to pay for the electrical energy generated by the energy producer. The second values ​​can be entered into the first data storage unit manually via a control unit connected to the energy feed-in unit or via the first communication interface.

[0025] In the control unit, the first data storage unit can be configured to store different second values ​​for different external energy consumers. The first communication interface can be configured to receive the first value along with information about the corresponding energy consumer from the external energy consumer. The control unit can then compare the first value with the second value for each external energy consumer and control the feed-in of electrical energy into the electrical supply network based on these comparison results. In this embodiment, the first communication interface receives data pairs consisting of the first value and the energy consumer or the energy consumer's identifier. Correspondingly, the first data storage unit stores data pairs consisting of the second value and the energy consumer or the energy consumer's identifier.This allows the energy producer to prioritize external energy consumers. For example, the energy producer can favor an external energy consumer to whose supply network the energy feed-in unit is connected. This means the second bid value for such an external energy consumer can be set lower relative to the second bid value for another external energy consumer, so that the latter is preferentially awarded the contract in the event of simultaneous bids. Furthermore, it can be stipulated that a specific external energy consumer is only prioritized for certain periods.

[0026] The control unit further comprises a synchronized clock which is configured to synchronize with a central clock via the first communication interface, wherein the first communication interface is configured to receive the first value together with a time validity of the first value from the external energy consumer, and the control unit is configured to check the time validity of the first value with the aid of the synchronized clock and only if the first value is time valid to control the feed-in of electrical energy into the electrical supply network.

[0027] Since grid load is constantly changing, it can be advantageous for external energy consumers to feed additional electrical energy into the grid only for a specific period. To avoid having to revoke the validity of the initial value through a further communication, it is helpful to assign a validity period to the initial value. Only during the validity period of the initial value does the control unit activate the energy feed-in unit to feed the generated electrical energy into the grid; that is, when the validity period of the initial value expires, the feed-in is also stopped. Using a synchronized clock, the control unit can then easily determine whether the initial value is still valid. Consequently, the synchronized clock simplifies communication and reduces the load on the communication network.The central clock, with which the synchronized clock synchronizes, can be provided, for example, by a network operator, municipal utility, or energy supplier. It is also conceivable that the central clock is provided by an institute, such as the German National Metrology Institute (PTB). In this way, the synchronized clock can be synchronized once or several times a day using the central clock via the first communication interface. The sender of the first value is also synchronized via the central clock.

[0028] The first communication interface can further be configured to receive the initial value along with an energy quantity from the external energy consumer, and the control unit can be configured to control the feed-in of electrical energy into the electrical grid depending on the received energy quantity. According to this embodiment, the control unit terminates the feed-in of electrical energy into the electrical grid when the requested energy quantity has been fed into the grid. This can be advantageous for precisely increasing grid stability, as only a specific amount of energy necessary to ensure grid stability is fed into the electrical grid.

[0029] The present disclosure further relates to a power feed-in unit with an inverter, wherein the power feed-in unit is configured to be connected to a control unit as described above. According to this embodiment, the control unit controls the inverter to feed the direct current generated by the power generator as alternating current into the electrical supply network.

[0030] The present disclosure further relates to an energy feed-in system comprising an energy feed-in unit, a control unit, and an energy generator as described above. The energy generator may be, for example, a photovoltaic system, a wind turbine, a heat pump, or any other type of energy generator.

[0031] The energy feed-in system can further include a battery for temporarily storing energy generated by the energy producer and means for determining the battery's state of charge. The energy feed-in unit is configured to control the feed-in of the electrical energy generated by the energy producer into the electrical grid depending on the battery's state of charge. The battery can be any type of energy storage device, in particular a lithium-ion battery, which enables the temporary storage of electrical energy and its subsequent delivery to a consumer. The means for determining the battery's state of charge can be, for example, a multimeter or a charge controller, which transmits the battery's state of charge to the control unit.In particular, it can be provided that, up to a certain minimum charge level of the battery, electrical energy generated by the energy producer can be fed into the electrical supply network even if the battery is not fully charged, which on the one hand can contribute to an increase in the grid stability of the electrical supply network, but on the other hand also ensures the security of supply in the event of a failure at the energy producer through the at least partially charged battery.

[0032] Another aspect of the present disclosure relates to a network infrastructure comprising a power supply system described above, an electrical supply network to which the power supply system is electrically connected, means for determining the network stability of the electrical supply network, and an external energy consumer with a second communication interface configured to send the first value to the first communication interface depending on the determined network stability of the electrical supply network. The network infrastructure may also be a virtual power plant, i.e., an interconnection of distributed power generation units into a network.

[0033] The means for determining the grid stability of the electrical supply network could, for example, consist of a large number of phasor (pulsed high-amplitude sinusoidal electromagnetic radiation) measuring devices that measure the current flow and the line status of the electrical supply network in real time. If the external energy consumer, using the means for determining grid stability, detects that additional balancing power is needed to maintain grid stability, it can send a relatively high initial value to the first communication interface via the second communication interface. This incentivizes the energy producer to feed its generated electrical energy into the electrical supply network. Consequently, the external energy consumer has an indirect means of controlling the increase in energy feed-in, i.e., increasing grid stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further advantages, details and features of the devices and systems described here will become apparent from the following description of exemplary embodiments and from the figures. Fig. 1 shows a schematic view of an embodiment of a network infrastructure with a power supply unit and a control unit in a power supply system, which is connected to an external energy consumer via an electrical supply network; and Fig. 2 shows a schematic view of a control unit. DETAILED DESCRIPTION

[0035] The Fig. 1Figure 1 shows a schematic view of a network infrastructure 200 with an energy feed-in system 100, which is connected via an electrical supply network 20 to an external energy consumer 80, for example, a network operator. The energy feed-in system 100 is located in a building 150 and comprises an energy feed-in unit 15, photovoltaic modules 30 mounted on the roof of the building 150, and a battery 40 for intermediate storage of electrical energy generated by the photovoltaic modules 30. The energy feed-in unit 15, the photovoltaic modules 30, and the battery 40 are electrically connected to each other within the building 150 via cabling 16. The cabling 16 consists of direct current (DC) lines. The energy feed-in unit 15 includes an inverter 17 for converting the DC generated by the photovoltaic modules 30 into alternating current (AC). The photovoltaic modules 30 can be connected to the inverter 17 in series or in parallel.The energy feed-in unit 15 is connected to the electrical supply network 20 via a house connection 19.

[0036] The energy feed-in unit 15 can also include other components besides the inverter 17. Fig. 1 Electrical components not shown, such as power status recording devices for phase-selective recording of active and reactive power occurring at the feed-in point, self-consumption recording devices for phase-selective recording of existing self-consumption and grid feed-in specification devices for phase-selective specification of a permissible grid feed-in power.

[0037] Between energy feed-in unit 15 and house connection 19, at least one electrical consumer 45 (for example, a refrigerator, a washing machine or a lamp) is connected, which is designed to consume energy generated by the photovoltaic modules 30, energy temporarily stored in the battery 40 or energy provided via the electrical supply network 20.

[0038] A control unit 10 is provided to control the feed-in of the energy generated by the photovoltaic modules 30 into the electrical supply network 20. The control unit 10 controls the energy feed-in unit 15 to start and stop the feed-in of the energy generated by the photovoltaic modules 30. Although the control unit 10 and the energy feed-in unit 15 are located in the Fig. 1Although the two units are depicted as separate entities, it is conceivable that they are configured as a single unit. The control unit 10 is connected to a battery charge level meter 47, which is configured to measure the state of charge of the battery 40 and transmit this information to the control unit 10. For example, the battery charge level meter 47 can transmit a value of electrical charge in ampere-hours (Ah) or a charge percentage to the control unit 10. The control unit 10 is also connected to the internet 60.

[0039] In the Fig. 1 In the illustrated embodiment, battery 40 is a DC-coupled battery storage device connected via a DC converter with charge controller (in Fig. 1(not shown) is connected to the photovoltaic modules 30 via the wiring 16. In particular, the battery 40 is designed as a lithium-ion battery. Alternatively, it is possible to use an AC-coupled battery storage system, in which the battery 40, similar to the consumer 45, is located between the energy feed-in unit 15 and the house connection 19. In this case, the battery 40 is connected to the energy feed-in unit 15 via a battery inverter with charge controller.

[0040] The energy feed-in system 100 is connected to the external energy consumer 80 via the electrical supply network 20. The external energy consumer 80 has a second communication interface 85, which is connected to the internet 60, so that the control unit 10 can communicate with the second communication interface 85 via the internet 60.

[0041] Furthermore, equipment 90 is provided for determining the grid stability of the electrical supply network. This equipment is designed to perform measurements regarding the stability of the electrical supply network 20. The grid frequency is automatically measured at several points in the electrical supply network 20 using digital measuring technology and electronic frequency meters. The equipment 90 for determining the grid stability of the electrical supply network is connected to the internet 60, and the measurement results are forwarded to the external energy consumer 80. This allows the external energy consumer 80 to receive real-time information regarding the stability of the electrical supply network 20 and to react accordingly, e.g., by requesting balancing power.

[0042] The Fig. 2Figure 1 shows a schematic view of an embodiment of a control unit 10, which is configured to be connected to a power supply unit 15. Preferably, the control unit 10 is the one described in the Fig. 1 Control unit 10 shown.

[0043] The control unit 10 comprises a first communication interface 50, a first data storage unit 55, a control unit 60, an authentication unit 65, a second data storage unit 70, a synchronized clock 75 and an operating unit 77.

[0044] Using the control unit 77, a user can enter values ​​into the first data storage unit 55. Specifically, the user can enter an electricity price in kilowatt-hours as the second value into the first data storage unit 55 via the control unit 77. Along with several other second values, the user can also enter further values ​​related to these second values ​​into the first data storage unit 55 via the control unit 77. For example, the user can enter a corresponding external energy consumer 80 and / or a battery charge level 40 into the first data storage unit 55 along with each second value.

[0045] The first communication interface 50 can receive initial values ​​from the external energy consumer 80 via the internet 60. Like the second value, the first value is an electricity price in kilowatt-hours. Along with the first value, the first communication interface 50 can receive further values ​​from the external energy consumer 80 via the internet 60. In this way, the external energy consumer 80 can additionally send an identification identifier of the sender, i.e., the external energy consumer 80, and / or the validity of the first value to the control unit 10.

[0046] After the first communication interface 50 receives the first value, the control unit 10 compares the received first value with the second value stored in the first data storage unit 55. If the received first value is higher than the stored second value, this means that the minimum price of the energy producer has been exceeded by the offer of the external energy consumer 80. In this case, the control unit 10 controls the energy feed-in unit 15 so that the energy generated by the photovoltaic modules 30 is fed into the electrical supply network 20. A settlement then takes place between the energy producer and the external energy consumer 80.

[0047] Further criteria for starting the feed-in of the energy generated by the photovoltaic modules 30 into the electrical supply network 20 may be that the first value is still valid, that the first value originates from a specific external energy consumer 80, and / or that the state of charge of the battery 40 does not fall below a predetermined minimum value. The control unit 10 checks whether these criteria are met.

[0048] To easily determine the validity of a first value received from the first communication interface 50, the control unit 10 has a synchronized clock 75, which synchronizes regularly at predetermined times with a central clock (not shown in the figures). The external energy consumer 80 is also synchronized with the central clock, so that validity information transmitted along with the first value can be easily checked for validity by the control unit 10. If a first value is no longer valid, the control unit 10 controls the energy feed-in unit 15 to stop feeding the energy generated by the photovoltaic modules 30 into the electrical supply network 20.

[0049] Normally, the energy generated by the photovoltaic modules 30 is only fed into the electrical grid 20 when the battery 40 is fully charged. However, in the present embodiment, it is possible for energy generated by the photovoltaic modules 30 to be fed into the electrical grid 20 even when the battery 40 is not fully charged. This can contribute to the stability of the electrical grid 20, particularly when the external energy consumer 80 requires balancing power in the short term. Since the battery charge level meter 47 keeps the control unit 10 informed about the state of charge of the battery 40, it is also possible to control the system in such a way that a minimum state of charge of the battery 40 is always maintained before energy is fed into the electrical grid 20.Furthermore, the control unit 10 can also control the energy feed-in unit 15 in such a way that even when the consumer 45 is consuming energy, the energy generated by the photovoltaic modules 30 is fed into the electrical supply network 20. In this case, the consumer 45 can be supplied with electricity from another energy provider.

[0050] Furthermore, the first communication interface 50 can receive an energy quantity from the external energy consumer 80 along with the first value. In this case, the control unit 10 terminates the feed-in of electrical energy by the energy feed-in unit 15 into the electrical supply network 20 when the requested energy quantity has been fed in. For this purpose, the control unit 10 can be equipped with a feed-in meter (in Fig. 1 (not shown) be connected.

[0051] Since communication between the external energy consumer 80 and the control unit 10 takes place via the public internet 60, it must be ensured that the control unit 10 detects forged initial values. Several security measures are in place for this purpose. Firstly, the control unit 10 includes an authentication unit 65, which is configured to authenticate whether the initial value originates from the external energy consumer 80. Furthermore, the control unit 10 includes a second data storage unit 70, which is configured to store a certificate for authenticating the external energy consumer 80. The second data storage unit 70 can also store an internet address to which confirmation of the received initial value must be sent. This internet address could, for example, be the internet address of the external energy consumer 80.If an incorrect initial value is received from the first communication interface 50 and a corresponding confirmation is sent to the internet address, the recipient knows that a fraud attempt has been made and can initiate appropriate countermeasures. Furthermore, it is possible that the second data storage unit 70 is configured as a read-only storage device, meaning that the certificate and / or the internet address were pre-stored in the second data storage unit 70. Additionally, the data stored in the second data storage unit 70 may be password-protected and / or encrypted.

[0052] According to another embodiment, it is possible that several external energy consumers 80 (in Fig. 1(not shown) send the respective first values ​​to the energy feed-in unit 15. In this case, the control unit 10 compares this multitude of received first values ​​with the second value stored in the first data storage unit 55 and selects the offer of the external energy consumer 80 with the highest first value, provided that this value is higher than the stored second value.

[0053] The energy consumption in building 150 is billed to the external energy consumer 80. For this purpose, several electricity meters are installed in building 150 (in Fig. 1(not shown) installed. This consists of a consumption meter, which counts the electricity drawn from the electrical supply network 20; a feed-in meter, which counts the electricity fed into the electrical supply network 20; and a yield meter, which counts the total electricity generated by the photovoltaic modules 30. Self-consumption is calculated as the difference between generated and fed-in energy.

[0054] The following is an embodiment of the present disclosure from the perspective of the party involved in the Fig. 1 The external energy consumer 80 shown is described.

[0055] The external energy consumer 80 is informed via the internet 60 by the grid stability control system 90 that positive control energy is required to compensate for a low grid frequency in the electrical supply network 20. The external energy consumer 80 decides to request a portion of the required control energy from the energy supply system 100 as secondary reserve or minute reserve. To do this, the external energy consumer 80 sends an electricity price (first value) along with the validity period of the first value to the first communication interface 50 via the second communication interface 85. Based on past experience, the external energy consumer 80 has chosen the first value to be attractive to the energy supply system 100, and the energy supply system 100 is highly likely to accept the external energy consumer 80's offer.If the energy feed-in system 100 accepts the offer from the external energy consumer 80, the energy feed-in system 100 feeds energy into the electrical supply network 20. As soon as the first value is no longer valid, the energy feed-in system 100 stops feeding energy into the electrical supply network 20. Based on the feed-in and the first value, the external energy consumer 80 compensates the operator of the energy feed-in system 100.

[0056] In the following, a further embodiment of the present disclosure will be presented from the perspective of the party involved in the Figure 1 and 2 The energy feed system 100 shown is described.

[0057] With sufficient sunlight, the photovoltaic modules 30 generate direct current, which is converted into alternating current by the inverter 17 and consumed by the load 45. If the battery 40 is not fully charged, it is charged.

[0058] The control unit 10 receives an initial value, along with a time validity period for that initial value, from the external energy consumer 80 via the first communication interface 50. Using the authentication unit 65, the control unit 10 verifies the authenticity of the initial value. After successful authentication, the control unit 10 compares the initial value with the second value stored in the first data storage unit 55. Furthermore, the control unit 10 uses the synchronized clock 75 to check whether the initial value is still valid.

[0059] If the control unit 10 determines that an acceptable offer has been received from the external energy consumer 80 (the first value is greater than the stored second value) and the first value is still valid, the control unit 10 controls the energy feed-in unit 15 such that the energy generated by the photovoltaic modules 30 is fed into the electrical supply network 20. Optionally, the control unit 10 can send a message to the external energy consumer 80 that the offer from the external energy consumer 80 has been accepted. After the validity of the first value expires, the control unit 10 terminates the energy feed-in to the electrical supply network 20. Subsequently, the grid feed-in data is sent to the external energy consumer 80 via the first communication interface 50 for billing purposes.

[0060] According to a further development of the embodiment described above, a prerequisite for energy feed-in is that the battery 40 is at least 50% charged. In this case, the control unit 10 checks the state of charge of the battery 40, as transmitted by the battery charge level meter 47, before initiating energy feed-in. If the state of charge of the battery 40 is at least 50%, energy feed-in begins. If the state of charge of the battery 40 is less than 50%, no energy feed-in occurs. Optionally, the control unit 10 can inform the external energy consumer 80 that its offer has not been accepted.

[0061] In the examples presented, different features and functions of the present disclosure have been described separately as well as in specific combinations. It is understood, however, that many of these features and functions can be freely combined with one another, unless explicitly excluded.

Claims

1. Control unit (10) for an energy feed-in unit (15) for feeding electrical energy into an electrical supply grid (20), wherein the energy feed-in unit (15) is electrically connected to the electrical supply grid (20) and an energy generator (30), and the control unit (10) comprises: a first communication interface (50), which is configured to receive, via a communication network (60), a first value from an external energy consumer (80), which is connected to the energy feed-in unit (15) via the electrical supply grid (20), a first data storage unit (55), which is configured to store a second value and a synchronized clock (75), which is configured to synchronize with a central clock via the first communication interface (50), wherein the control unit (10) is configured to compare the first value with the second value and to control the feeding-in of the electrical energy into the electrical supply grid (20) depending on the comparison result, characterized in that the first communication interface (50) is configured to receive the first value together with a temporal validity of the first value from the external energy consumer (80) and the control unit (10) is configured to check the temporal validity of the first value with the aid of the synchronized clock (75) and to control the feeding-in of the electrical energy into the electrical supply grid (20) only in the case of a temporal validity of the first value.

2. Control unit (10) according to claim 1, further comprising an authentication unit (65), which is configured to authenticate whether the first value originates from the external energy consumer (80).

3. Control unit (10) according to claim 2, further comprising a second data storage unit (70), which is configured to store a certificate for authentication of the external energy consumer (80) and / or an Internet address for sending a confirmation of the received first value via the first communication interface (50).

4. Control unit (10) according to claim 3, wherein the second data storage unit (70) is a read-only memory, and / or the data stored in the second data storage unit (70) are stored password-protected and / or encoded.

5. Control unit (10) according to one of the preceding claims, wherein the first communication interface (50) is configured to receive, via the communication network (60), respective first values from a plurality of external energy consumers (80).

6. Control unit (10) according to one of the preceding claims, wherein the first data storage unit (55) is configured to store a plurality of second values each together with a battery charge state and / or a time indication and the control unit (10) is configured to control the feeding-in of the electrical energy into the electrical supply grid (20) depending on the battery charge state and / or the time indication.

7. Control unit (10) according to claim 5, wherein the first data storage unit (55) is configured to store different second values for different external energy consumers (80), the first communication interface (50) is configured to receive the first value together with an indication of an associated external energy consumer (80) from the external energy consumer (80) and the control unit (10) is configured to compare, for each external energy consumer (80), the first value with the second value and to control the feeding-in of the electrical energy into the electrical supply grid (20) depending on these comparison results.

8. Control unit (10) according to one of the preceding claims, wherein the first communication interface (50) is configured to receive the first value together with an amount of energy from the external energy consumer (80) and the control unit (10) is configured to control the feeding-in of the electrical energy into the electrical supply grid (20) depending on the received amount of energy.

9. Energy feed-in system (100) comprising the control unit (10) according to one of claims 1 to 8 and an energy feed-in unit (15) having an inverter (17), wherein the energy feed-in unit (15) is connected to the control unit (10).

10. Energy feed-in system (100) according to claim 9, further comprising a battery (40) for intermediate storage of energy generated by the energy generator (30) and means (47) for determining the charge state of the battery, wherein the control unit (10) is configured to control the feeding-in of the electrical energy generated by the energy generator (30) into the electrical supply grid (20) depending on the charge state of the battery (40).

11. Energy feed-in system (100) according to claim 9, further comprising a battery (40) for intermediate storage of energy generated by the energy generator (30), wherein the control unit (10) is configured to control the feeding-in of the electrical energy into the electrical supply grid (20) even when the battery (40) is not fully charged.

12. Energy feed-in system (100) according to one of claims 9 to 11, wherein the energy feed-in unit (15) is configured to be electrically connected to a load (45) and the control unit (10) is configured to control the feeding-in of the electrical energy into the electrical supply grid (20) even when the load (45) can consume energy generated by the energy generator (30).

13. Grid infrastructure (200) comprising the energy feed-in system (100) according to one of claims 9 to 12, an electrical supply grid (20), to which the energy feed-in system (100) is electrically connected, means (90) for determining the grid stability of the electrical supply grid and an external energy consumer (80) having a second communication interface (85), which is configured to send, depending on the determined grid stability of the electrical supply grid (20), the first value to the first communication interface (50).