EP4302101A1

EP4302101A1 - Method for determining an electrical transfer energy flow into or out of a reserve unit, use of the result of this method, and control system for carrying out the method

Info

Publication number: EP4302101A1
Application number: EP22716318.5A
Authority: EP
Inventors: Bastian Hackenberg; Jakob Giza
Original assignee: Sonnen GmbH
Current assignee: Sonnen GmbH
Priority date: 2021-03-05
Filing date: 2022-03-07
Publication date: 2024-01-10
Also published as: US20240063639A1; WO2022184212A1; DE102021105425B3

Abstract

The invention relates to a method for determining an electrical transfer energy flow (E) into or out of a reserve unit (RE) comprising: • an electrical consumer group (D), • an electrical energy storage system (ESS) comprising an electrical energy store (B) and • an electrical energy generation apparatus (PV), wherein the reserve unit (RE) is connected to an electrical transmission network (G) via a first electrical counter device (Z1) for ascertaining the network energy flows between the transmission network (G) and the reserve unit (RE). According to the invention, the method comprises the steps of: • ascertaining an energy consumption flow (Ed) of the electrical consumer group (D) per unit of time; • ascertaining a network energy flow (Eg2re) from the electrical transmission network (G) into the reserve unit (RE) per unit of time; • ascertaining a generator energy flow of the electrical energy generator apparatus (PV) per unit of time; • ascertaining a store energy flow (Ebe) between the electrical energy store (B) and the electrical consumer group (D) and/or the electrical transmission network (G) per unit of time; and • determining the transfer energy flow (E) in the unit of time using the energy conversion law, wherein additional electrical energy flows are ascertained within the reserve unit (RE) by additional counter devices (Z2, Z3) such that, for different scenarios and boundary conditions, the transfer energy flow (E) is present as a measured value of a single of the first or one of the additional electrical counter devices (Z1, Z2, Z3). The invention also relates to the use of the result of this method and to a control device (SE) configured and designed to carry out this method or to the use of the method results.

Description

Method of determining an electrical transfer energy flow into or out of a reserve unit, use of the result of this method and control system for carrying out the method

Private and commercial operators of electrical energy generation devices, for example photovoltaic systems, wind turbines, biomass systems and combined heat and power plants, are currently feeding some of the self-generated electrical energy in the form of electricity into electrical transmission networks. In many countries there are systems in place that pay the operator feed-in tariffs for the delivery of electrical energy generated from renewable sources into the transmission grid. The level of feed-in tariffs has fallen significantly in recent years, particularly in Germany. Therefore, self-consumption of self-generated electrical energy by operators' own electrical consumer groups connected to the transmission network has become more and more economically interesting for the operators of the energy generating devices. The quantity of the operator's electrical consumers, forming an electrical consumer group, is defined via a common grid connection point.

Within the scope of this patent application, the electrical energy generated by the private or commercial operator of the energy generating device himself in the form of electrical, so-called green electricity, is referred to as “green energy”. In contrast, the electrical power drawn from the transmission grid is referred to as gray power, which is referred to as "grey energy" in the following. The term gray energy is used regardless of how the gray energy was generated. The term gray energy is therefore also used within the scope of the present invention for energy generated in a climate-neutral manner, which is supplied from the transmission network to the electrical consumer groups of the operators.

Coupling an electrical energy storage system to the consumer group connected to the transmission grid is a suitable way of increasing the proportion of self-consumption on the part of the operator. Such an electrical energy Storage system has an electrical energy store, preferably in the form of a chargeable and dischargeable battery device. At times when the electrical power requirement of the electrical consumer group is greater than the electrical power provided by its own energy generating device, the missing electrical power can be made available from the battery device. However, it is illegal for regulations to store gray energy from the transmission grid in the battery system and feed it into the transmission grid at a later point in time as supposed green energy. Since the metrological infrastructure currently does not make it possible to clearly determine whether green energy or gray energy from the battery facility is being fed into the transmission grid or is being consumed by the consumer group via the battery facility, the combined storage of green energy and gray energy in one and the same battery facility is not possible. Installing two separate battery devices, each of which is only charged with green energy or only with gray energy, is uneconomical and does not conserve resources.

However, the operators of the transmission grids and the electricity traders have a great interest in being able to use privately or commercially installed energy storage systems to serve the grid or energy trading. The operator of the energy storage systems receives remuneration for such uses. It is therefore necessary to determine the energy flows referred to as transfer energy flows in this patent application in such a way that this balance is suitable for a reimbursement statement to the operator of the energy storage systems.

From the point of view of the transmission system operators, so-called reserve units, which were formerly also referred to as technical units, usually have such a performance potential for the provision of electrical control reserve that this negative and/or positive control reserve in the form of primary control reserve is now referred to as FCR (Frequency Containment Reserve). , or secondary control power, now referred to as aFRR (automated Frequency Restoration Reserve), in the range of many megawatts. Classically, these are, for example, individual water or gas power plants for generating electrical energy with a power range of many megawatts, these power plants being ramped up or throttled accordingly to provide the desired positive or negative electrical control power.

In the context of the present invention, however, the technical term “reserve unit” is defined much smaller than is customary in the art. This means that a reserve unit within the meaning of the invention is already present, for example, in the form of a system that has an individual electrical energy store coupled to an individual, defined electrical consumer group. Specifically, the reserve unit is defined as the sum of all electrical power units whose electrical power flows between this sum of power units and an external transmission network can be recorded via a common network connection point with a usually calibrated electrical meter device. The electrical power units are designed:

- purely for absorbing electrical energy, for example all the usual electrical consumers in a building network,

- Energy storage as a combination unit for both receiving and delivering electrical energy, such as a trained as a battery building, or

- Purely for the delivery of electrical energy, for example a photovoltaic system mounted on or on the building.

In the context of the present invention, the term “purely for absorption” means that it is not technically possible for the electrical power unit to deliver electrical energy or only to an insignificant extent of less than 10% compared to the electrical energy consumption. The correspondingly reversed definition applies to the term "purely for sale".

According to this far-reaching definition, a reserve unit that is preferred in the context of this invention has: - an electrical consumer group defined via a grid connection point consisting of electrical power units purely for the consumption of electrical energy

- An electrical energy generating device as an electrical power unit purely for the delivery of electrical energy and

- An electrical energy storage system as an electrical power unit for both receiving and delivering electrical energy.

This combination of electrical power units is already found in many private and/or commercial buildings that are connected to a transmission network via a network connection point. This network connection point has a preferably calibrated, first electrical meter device that records the electrical energy flow between the connected transmission network and the reserve unit. This first electrical meter device determines a measured value Z1d as the network energy flow from the transmission network into the reserve unit. Furthermore, the first electrical meter device determines a measured value Z1u as the network energy flow from the reserve unit out into the electrical transmission network. The first electrical counter device is therefore preferably designed as a bidirectional counter.

In the context of this invention, electrical energy flows are to be understood as amounts of electrical energy that flow between defined connection points. By considering defined electrical energy flows at defined time intervals, the electrical energy flow becomes an electrical power flow. In the following, however, electrical energy flows are primarily discussed, because the associated time intervals are not important.

DE 10 2017 121 457 A1 discloses a system and a method for measuring electrical power, which solves the problem of the precise balancing of separate recording of green electricity and gray electricity and thus the desired determination of the transfer energy flows through the use of additional measurement technology hardware in the area of consumer groups in the form of building networks. However, this system and method has the disadvantage that a large number of other counter devices must be installed in combination with an energy flow direction sensor in order to achieve the desired goal. The present invention is therefore based on the object of providing a method which, with less effort, enables transfer energy flows in us from a reserve unit to be determined with accurate balancing. Furthermore, it is the object of the invention to provide a use of the method results and a control system that implements this use of the method results.

This object is achieved by a method with the method steps according to claim 1, by using the results of such a method with the features according to claim 11 and by a control system with the features according to claim 19.

According to the invention, the method has the following method steps:

Determination of a recording energy flow including the electrical consumer group in a defined time interval,

Determining a network energy flow between the electrical transmission network and the reserve unit in the defined time interval, determining a generator energy flow of the electrical energy generation device in the defined time interval, determining a storage energy flow between the electrical energy storage device of the electrical energy storage system and the electrical consumer group and/or the electrical transmission network in the defined time interval and • determination of the transfer energy flow in the defined time interval using the law of conservation of energy, with further electrical energy flows within the reserve unit between at least two assemblies selected from:

- the energy storage system, - the energy generating device and

- The electrical consumer group are determined by further electrical counter devices in such a way that in a case distinction selected from the two case groups: - the energy generating device generates more electrical power than the electrical consumer group requires and

- The energy generating device generates no electrical power or the same amount or less electrical power than the electrical consumer group requires combined with a boundary condition selected from:

- the electrical energy store charges and

- The electrical energy store discharges, the transfer energy flow for the selected case group with the combined boundary condition is present as a measured value of a single one of the first or one of the further electrical meter devices.

The procedural steps of determining different energy flows in the defined time interval can be carried out directly or indirectly. Arranging and reading one of the electrical metering devices selected from the group of the first electrical metering device and the other electrical metering devices in such a way that the measured value determined by the electrical metering device directly corresponds to the energy flow to be determined is regarded as directly determining an energy flow to be determined. This applies, for example, to the network energy flow between the electrical transmission network and the reserve unit through the first electrical metering device in the area of the network connection point. As already stated, the first electrical meter device determines the flow of electrical energy from the transmission system into the reserve unit with a measured value Z1d and the flow of electrical energy from the reserve unit into the transmission system with a measured value Z1u. Indirect determination of an energy flow to be determined is the calculation of measured values from several electrical metering devices selected from the group of the first electrical metering device and the other electrical metering devices in such a way that the energy flow to be determined is calculated and thus results indirectly. This applies, for example, to the proportion of the electrical energy generated by the reserve unit with the aid of the electrical energy generation device itself, which is absorbed by the electrical consumer group. In particular, if the electrical energy generating device generates more total electrical power than is required in the electrical consumer group, part of the total power generated flows as feed power into the transmission network and/or part of the total power generated flows into the electrical energy to charge the electrical energy store -Storage system. In this case, the proportion of consumer energy flow from the electrical energy generating device's can only be determined indirectly by calculating the measured values from a number of electrical metering devices.

Even if an energy flow to be determined according to the invention only drops as a secondary result when measured values from different electrical meter devices are offset, this implements the claimed feature of determining the energy flow.

The goal according to the invention of selecting and arranging further electrical meter arrangements in the reserve unit in such a way that the transfer energy flow is ultimately available as a measured value from a single electrical meter device has the following background. In order for the determined transfer energy flow to be billable for a balance sheet, it must be available as a measured value from a calibrated electrical meter. Even if two measured values from two calibrated metering devices are used to calculate the transfer energy flow from the two measured values, the offsetting of two measured values only represents a measured variable and no longer a measured value in accordance with the regulatory provisions for the energy industry that apply in Germany. Metrics are not suitable for balance sheets. leave readings are generated exclusively via calibrated metering devices in accordance with the regulations mentioned. However, the use of a plurality of calibrated electrical counting devices is associated with significantly increased costs and increased administrative effort. It is therefore in the interest of the operator of the reserve units described to keep the number of calibrated electrical metering devices as small as possible, but at the same time to have a balance-capable determination of the transfer energy flow.

Within the scope of the present invention, however, no terminological differentiation is made between measured values and measured variables in the manner described above. Each of the electrical metering devices delivers measured values, regardless of whether they are calibrated or not. At least according to the regulations applicable in Germany, those electrical metering devices whose measured values represent the transfer energy flows for the respective case group with the combined boundary condition must be calibrated so that they can be used for business accounting.

The determination of the transfer energy flow in the scenario of the specific case group including combined boundary conditions is carried out using the law of conservation of energy. Present in a closed system

Reserve unit with a defined, own energy production including the connected transmission network, the amount of available energy must be constant. The energy represents a conserved variable. As a result, the energy flows within the reserve unit and the energy flows flowing into and out of the reserve unit can be selected and related to one another in such a way that the transfer energy flows between the reserve unit that serve the grid or trade energy are different and let the transmission network calculate it. The determination of the generator energy flow is preferably carried out as a determination of a generator-to-consumer energy flow from the electrical energy generating device into the electrical consumer group in the defined time interval. This means that the proportions of the energy generated Generation device outgoing energy flows that are fed into the transmission network and / or used to charge the electrical storage device are to be deducted from the total energy flow generated by the energy generation device. In alternative variants of the method, the entire energy flow generated by the energy generating device is determined, which is then related to the other energy flows determined in such a way that the transfer energy is calculated taking into account the law of conservation of energy.

Cumulatively or alternatively, the ascertainment of the consumption energy flow is carried out as a ascertainment of the consumption energy flow of the electrical consumer group in the defined time interval. It is exclusively about the input power required by the electrical consumer group.

If the generation energy flow is determined as determining a generator-to-consumer energy flow from the electrical energy generation device into the electrical consumer group in the defined time interval and the determination of the intake energy flow as a determination of the intake energy flow electrical consumer group in the defined time interval, the transfer energy flow is determined using the energy conservation law using the formula:

E = (Ed - Epv2d - Ebe - Eg2re) with: E transfer energy flow,

Ed absorption energy flow of electrical consumer group,

Epv2d producer-to-consumer energy flow,

Ebe storage energy flow between the electrical energy storage device and the electrical consumer group and/or the electrical transmission network and Eg2re network energy flow from the electrical transmission network into the reserve unit Also preferred is the method step of determining the generator energy flow from the electrical energy generating device to the electrical consumer group in the defined time interval with a first additional electrical counter device with a measured value Z2d for an energy flow in the direction of the electrical consumer group and/or in the direction of the electrical energy storage system and with a measured value Z2u for an energy flow oriented in the opposite direction, the electrical energy generating device being connected between the first electrical meter device and the first additional electrical meter device in such a way that electrical current generated with the electrical energy generating device can flow both via the first electrical counter device can be fed into the electrical transmission network, as well as via the first additional meter device for the electrical consumer group and/or for the el electrical energy storage system can be conducted, with the producer-to-consumer energy flow always being the smaller energy flow of the two energy flows:

- absorption energy flow and

- the entire generator energy flow is determined.

The first further counter device serves to determine further energy flows within the reserve unit. These are represented by the measured values Z2d and Z2u. When determining the transfer energy flow for the two case groups (ratio of generated electrical power to the power consumption of the electrical consumer group) combined with the two possible boundary conditions (battery is charging or battery is discharging), it then turns out that the first further meter device for the determination of the transfer energy flow is not required. The method is preferably additionally designed such that a total generator energy flow is determined by forming the difference between the energy flow measured value Z2d of the first additional meter and the measured value Z1d of the network energy flow and adding the following difference to it is: the measured value Z2u is subtracted from the measured value Z1u as the network energy flow from the reserve unit into the electrical transmission network. The entire generator energy flow includes all of the energy generating device, in particular a photovoltaic system, generated electrical energy that can flow in at least one direction, selected from the group comprising the electrical consumer group, the transmission network and the electrical energy storage of the electrical energy storage - Systems. A different arrangement of the first and second counter device results in a correspondingly different calculation of the entire generator energy flow.

Furthermore, the method is preferably designed such that a storage-to-consumer energy flow from the electrical energy storage device of the electrical energy storage system to the electrical consumer group is carried out in the defined time interval by forming a difference as follows: from the determined recording - Energy flow is deducted from the energy flow Z2d measured with the first further electrical counter device if this difference formed is greater than zero and if the difference formed is less than zero, the storage energy flow is set equal to zero. With a different arrangement of the first second metering device, there is a correspondingly different calculation of the storage-to-consumer energy flow.

A particularly preferred development of the method is characterized in that an energy flow into the electrical energy storage device is determined with a measured value Z3d and the storage energy flow from the electrical energy storage device with a measured value Z3u using a second further counter device connected upstream of the electrical energy storage device. The second further counter device is preferably designed as a two-direction counter. Furthermore, the second further counter device is preferably used in the form of a calibrated counter device. In this way, energy flows flowing into and out of the electrical energy store can be determined in a suitable manner for the balance. In a further development of the method variant with the first and second further counter device described above, it is provided that the two case groups relating to a size comparison of the intake energy flow to the total generator energy flow via the measured values of the first counter device and via the measured values of the second further counter device such as can be determined as follows: For the size comparison, the entire generator energy flow corresponds to Z1u-Z1d and the intake energy flow corresponds to Z3u-Z3d. This follows from the fact that the following equations hold:

- the total generator energy flow is equal to Z2d-Z1d + Z1u-Z2u and

- the absorption energy flow is equal to Z2d-Z3d + Z3u-Z2u, where the term Z2d-Z2u appears in both equations. Consequently, this term can be omitted when comparing the magnitudes of the two energy flows.

Also preferred for the case group is the total generator energy flow is greater than the intake energy flow:

- under the boundary condition of a charging electrical energy store, i.e. Z3d>0, the transfer energy flow is determined as the measured value Z1d,

- under the boundary condition of a discharging electrical energy storage device, i.e. Z3u>0, the transfer energy flow is determined as the measured value Z3u and for the case group the total generator energy flow is less than or equal to the receiving energy flow, including the case that the total Generator Energy Flow is 0:

- under the boundary condition of a charging electrical energy store, i.e. Z3d>0, the transfer energy flow is determined as the measured value Z3d,

- Determined under the boundary condition of a discharging electrical energy store, ie Z3u>0, the transfer energy flow as the measured value Z1u.

This follows from the fact that the amount of the transfer energy flow for the first case group (the total generator energy flow is greater than the intake energy flow) is calculated as Z3u + Z1d, with the measured value Z3u , which corresponds to a discharge current of the electrical energy store, must be zero must, and under the boundary condition of a discharging electrical energy store Z1d must be equal to zero, because the electrical energy generation device provides sufficient electrical power for the electrical consumer group, so that no energy flow from the electrical transmission network is necessary. Furthermore, for the same reason, the energy flow in the form of the discharge current of the electrical energy store cannot be intended for the electrical consumer group. The only possibility remains that the energy flow in the form of the discharge current of the electrical energy store flows as a transfer energy flow into the electrical transmission network. Since the electrical energy store cannot discharge and charge at the same time, the meter reading Z1d must be zero in this scenario.

For the second group of cases: the total generator energy flow is less than or equal to the absorption energy flow, the amount of the transfer energy flow is determined as Z3d + Z1u, where under the boundary condition of a charging electrical energy storage device the meter reading Z1u is equal to zero must be, because the entire generator energy flow flows into the electrical consumer group, so that nothing can be fed into the electrical transmission network. Furthermore, the electrical energy store charges and therefore cannot simultaneously provide an electrical energy flow that flows into the electrical transmission network. Under the boundary condition of a discharged electrical energy store, the meter reading Z3d is necessarily equal to zero and the meter reading Z1u corresponds to the transfer energy flow, which flows from the electrical energy store into the electrical transmission network, because the entire generator energy flow in the direction of the electrical consumer group drains. The same applies to the formula of the amount of the transfer energy flow Z3d + Z1u for the extreme case that the generator energy flow is zero because the electric power generation device does not generate any electric power.

The object on which the invention is based is also achieved by using the results of one of the methods described above, wherein to determine transfer energy flows between an electrical see the transmission network and a procedural reserve unit, the measured values of at least one electrical metering device are determined who have the transfer energy flow to be determined under procedurally defined case groups and boundary conditions.

The concept of the reserve unit according to the method and the case groups and boundary conditions according to the method fully includes the previous statements made on the method according to the invention. This term was chosen to avoid repetition in this reference.

The method according to the invention must go through the method steps at least once to determine further electrical energy flows in such a way that, using the case distinction with the case groups including boundary conditions, the desired result is the transfer energy flow to be determined as a measured value of a single one of the first or one of the further electrical counts learning facilities are available. Once this goal has been achieved for a reserve unit together with its electrical counter devices, the method result obtained is used repeatedly in order to carry out the desired determination of the transfer energy flow as often as desired.

If no change is made to the structure of the reserve unit components, it also remains the case with the help of which measured values of the electrical counter devices for which case group boundary condition constellations the transfer energy flow can be determined as a simple measured value. The transfer energy flow is determined in defined procedural steps, which, however, can only be defined if the results of the method described above are available. The use of these process results is therefore available in the form of an independent process.

The use described above is preferably developed in such a way that system-maintaining intake energy flows into the electrical energy storage system that are not influenced by the intake energy flow of the electrical user group are included, are determined and balanced against the specific electrical transfer energy flow.

The system-maintaining energy flows include in particular the following energy flows:

• an energy flow caused by a standby power consumption of an inverter installed in the energy storage system when the electrical energy storage device is empty and cannot guarantee the standby power consumption,

• an energy flow caused by a trickle charge of the electrical energy store belonging to the electrical energy store system and

• an energy flow caused by a cyclical full charge of the electrical energy store belonging to the electrical energy store system.

What all system-maintaining intake energy flows have in common is that they cause an energy exchange between the electrical transmission network and the electrical energy store of the electrical energy storage system. These energy flows are included in the determination of the transfer energy flow. This falsifies the result of the transfer energy flow because it is an energy consumption in the reserve unit and not the storage of gray current in the electrical storage device.

The standby power consumption of the inverter usually amounts to a characteristic value of a few watts, which is drawn from the electrical transmission network in emergency operation, if the electrical energy store is so empty that the power supply to the inverter cannot be provided by the electrical energy store. In this scenario, the reserve unit has an absorption-transfer energy flow of a few watts. However, this is not an energy flow that serves the grid or the energy market, but a system-preserving energy flow that must be taken into account in a billing-relevant balancing of the transfer energy flow.

The situation is similar with the flow of energy from the electrical transmission network into the electrical energy store caused by the trickle charge of the electrical energy store. For a sustainable use of the electrical energy store, it is necessary that this is protected from a so-called deep discharge. This applies in particular when the electrical energy store is a chargeable battery. For this purpose, the electrical energy store is controlled, if required, in such a way that it is charged up to a defined charge level by means of an electrical energy flow from the electrical transmission network. This is also an emergency solution in the event that the electrical energy generating device cannot provide any or too little energy. This system-maintaining energy flow also appears as part of the specific transfer energy flow, but is neither useful for the grid nor for the energy market. Consequently, this energy flow must also be taken into account in a billing-relevant balancing of the transfer energy flow.

It is also necessary for sustainable use of the electrical energy store that it has to be fully charged once within a defined time window. If this cannot be guaranteed by the electrical energy generating device in the required time window, the required energy flow is obtained from the electrical energy transmission network as an emergency solution. The usual electrical power for this corresponds regularly to the maximum possible electrical input power of the inverter, which ensures the conversion of alternating current from the electrical transmission network into the direct current required for charging the electrical energy storage device.

All of the system-maintaining energy flows mentioned can be identified using characteristic values in the transfer energy flow. The recognition is simplified by the fact that the boundary conditions mentioned: - Electrical energy generating device provides no or too little energy

- The state of charge of the electrical energy store is correspondingly small and - The full charge cycle is achieved without the electrical energy store being fully charged once in this full charge cycle. registered by the tax system. This information makes it easier to calculate the system-maintaining energy flows from the determined transfer energy flows.

Furthermore, preferred for all the above-described uses of method results, these are further developed in such a way that they can be used in real time during defined time intervals in the range from 10 seconds to 15 minutes, preferably in the range from 30 seconds to 10 minutes and particularly preferably in the range of one minute up to five minutes is carried out. The defined time windows may vary. For example, a significant status change can result in the time window ending prematurely and a new one beginning. This applies, for example, whenever the power of the electrical energy generating device exceeds or falls below the requirement on the part of the electrical consumer group. The occurrence of the case groups described above with the respective boundary conditions represent, for example, such significant status changes. Independent of the defined time interval, balancing periods can be selected and defined within which the determined transfer energy flows are balanced and thus become relevant for billing for the operator of the reserve unit.

As an alternative to evaluation in real time, the transfer energy flows can also be determined subsequently using stored energy flow data sets. The same statements made above regarding the length of the time intervals and the additional definable balancing periods apply. One of the above-described methods or one of the above-described use of method-related results is preferably carried out in a control unit of the electrical energy storage system. This means that the entire logic of the required algorithm is located in a decentralized manner within the reserve unit. Alternatively, it is also possible for the method or the use of results according to the method to run in an evaluation unit arranged outside of the reserve unit. For this variant it is therefore necessary for the data to be measured in the reserve unit, in particular relating to the energy flows prevailing there, to be transmitted to the evaluation unit.

Finally, the present invention relates to a control system designed and set up to carry out one of the methods described above or designed and set up to use results according to the method as described above. For this purpose, the control system can be completely decentralized, for example embodied within the reserve unit. Alternatively, some or all of the system components can be positioned elsewhere than in the decentralized reserve unit.

Purely by way of example, an exemplary embodiment of the invention is explained in more detail below with reference to the figures.

Show it:

FIG. 1 shows a schematic representation of a reserve unit RE connected to an electrical transmission network G with an electrical energy generation device PV with an electrical energy storage system ESS having an electrical energy storage device B;

FIG. 2 Energy flows that can occur between the interacting system components shown in FIG. 1; FIG. 3a Energy flows between the system components from FIGS. 1 and 2 for a first case group Epv<=Ed with the boundary condition of a discharging electrical energy store B;

FIG. 3b energy flows between the system components from FIGS. 1 and 2 for the first case group Epv<=Ed with the boundary condition of a charging electrical energy store B;

FIG. 4a Energy flows between the system components from FIGS. 1 and 2 for the first case group Epv=0<Ed for the special case Epv=0 and with the boundary condition of a discharging electrical energy store B;

FIG. 4b energy flows between the system components from FIGS. 1 and 2 for the first case group Epv=0<Ed for the special case Epv=0 with the boundary condition of a charging electrical energy store B; FIG. 5a Energy flows between the system components from FIGS. 1 and 2 for a second case group Epv>Ed with the boundary condition of a discharging electrical energy store B;

FIG. 5b Energy flows between the system components from FIGS. 1 and 2 for the second case group Epv>Ed with the boundary condition of a charging electrical energy store B and

FIG. 6 shows a flow chart to clarify the use of method results for determining the transfer energy flow.

1 shows a schematic representation of a reserve unit RE connected to an electrical transmission network G with an electrical energy generating device PV and an electrical energy storage system ESS having an electrical energy store B. Such reserve units RE often represent electrical building networks into which the electrical energy generating device PV and the electrical energy storage system ESS are integrated. These electrical building networks are connected to the electrical transmission network G via what is known as a network connection point NAP. To the energy flows from the electrical transmission network G in the reserve unit RE and from the reserve unit RE in the electrical transfer To balance transmission network G in a way that is relevant to billing, a usually calibrated first electrical meter device Z1 is used at this interface, preferably in the form of a two-way meter, particularly preferably a so-called smart meter. The two directions for detecting the flow of energy Z1u from the reserve unit RE into the electrical transmission system G and the flow of energy Z1d from the electrical transmission system G into the reserve unit RE are indicated by the pair of arrows pointing up and down. A first additional electrical counter device Z2 is also preferably designed as a bidirectional counter. Between the first electrical metering device Z1 and the first additional electrical metering device Z2, the electrical energy generating device PV is integrated into the reserve unit RE in a branching manner. The first further electrical meter device Z2 thus determines a meter reading Z2d for the energy flows directed downwards to an electrical consumer group D of the reserve unit RE and a meter reading Z2u for the energy flows directed upwards in the direction of the electrical transmission network G. Which ones are involved in detail is explained below in connection with FIG.

Below the first additional electrical meter device Z2 is on the one hand the already mentioned electrical consumer group D and on the other hand, in a separate electrical branch, the electrical energy storage system ESS with the chargeable and dischargeable electrical energy storage device B. The energy flows in and out the electrical energy storage system ESS can be recorded via a second additional electrical counter device Z3. The energy flows flowing in the direction of the electrical energy store B are recorded as measured values Z3d and the energy flows flowing from the electrical energy store B in the direction of the electrical transmission system G are recorded as measured values Z3u. Furthermore, the electrical energy storage system ESS also has a control device SE. This control device SE is used for the best possible control of all energy flows between the components of the overall system shown, as explained below.

FIG. 2 shows the energy flows that can occur between the interacting system components shown in FIG. 1 using the representation of the system components that is identical to that in FIG.

The sum of the energy flows that flow from the electrical transmission system G into the reserve unit RE is recorded as the measured value Z1d. Specifically, these are the following energy flows:

- Eg2d, an energy flow that reaches electrical consumer group D,

- Esys, an energy flow that serves to maintain the system in special system states and

- Er, a transfer energy flow from the electrical transmission network G to the electrical energy storage device B.

In the opposite direction, the measured value Z1u represents the sum of the energy flows that flow from the reserve unit RE into the electrical transmission network G. Specifically, these are the following energy flows:

- Epv2g, a feed-in energy flow of the electrical power generation device PV in the electrical transmission network G and

- Eh, a transfer energy flow from the electrical energy storage device B to the electrical transmission network G.

If the electrical energy store B is designed in such a way that it can only ever be either charged or discharged, there can only ever be a transfer energy flow Er into the reserve unit RE or a transfer energy flow Eh from the reserve unit RE.

The energy flows from the electrical energy generation system PV can be made up of the following components: - Epv2g, the previously mentioned feed-in energy flow of the electrical energy generating device PV into the electrical transmission grid G,

- Epv2b, an energy flow that is stored in the electrical energy storage device B to increase the self-consumption rate of the reserve unit and

- Epv2d, an energy flow, the supply device from the electrical Energieerzeu PV to the electrical consumer group D arrives. The last two of these three energy flows flow downwards through the first further electrical counter device Z2, shown schematically, and together form the measured value Z2d with Z1d=Eg2d+Esys+Er. The first energy flow Epv2g flows upwards schematically and together with Er, the transfer energy flow from the electrical transmission system G into the electrical energy store B, forms the measured value Z1u.

The energy flows Eg2d and Epv2d flow into the electrical consumer group D below the first further electrical meter device Z2. The energy flows Er, Esys and Epv2b, which are directed schematically downwards, flow Shen via the second further electrical meter device Z3 into the electrical energy store B and can be summed up in the process read Z3d as measured value. In the opposite direction, the transfer energy flow Eh flowing from the electrical energy storage device B and the energy flow portion in the form of the storage-to-consumer energy flow Eb2d remain, which also reaches the electrical consumer group D in order to meet their power requirements in the form of the collected consumers together with to cover the energy flow shares Epv2d and Eg2d. The sum of the energy flows Eb2d and Eh forms the measured value Z3u of the second additional electrical counter device Z3. The control device SE of the electrical energy storage system ESS is set up and designed in such a way that Eg2d is minimized. This energy flow control is performed by algorithms using a range of current and forecast parameters. These include in particular: - the power requirement of the electrical consumer group D,

- the amount of energy generated by the electrical energy generating device PV,

- the amount of energy stored in the electrical energy store B and - the economic relevance of transfer energy flows Eh and Er in a balancing with the energy service provider who sells electrical power to the operator of the reserve unit via the electrical transmission network G.

A determination of the transfer energy flows Eh and Er that is as simple as possible is of interest. These two energy flows are collectively referred to below as the transfer energy flow E. If one considers the reserve unit RE and the electrical transmission network G connected to it as a closed system, the following applies according to the law of conservation of energy:

E = Ed - Epv2d - Ebe - Eg2re

In this case, Ebe is the entire energy flow flowing from the electrical energy store, and Eg2re is the entire energy flow flowing between the electrical transmission network G and the reserve unit RE.

All energy flows except for the transfer energy flow E sought are shown below in a notation using the first electrical metering device Z1 and the further electrical metering devices Z2 and Z3, which we described above are arranged in the reserve unit.

From Ed = Eg2d + Epv2d + Eb2d follows with: Eg2d + Epv2d = Z2d - Z3d and Eb2d = Z3u - Z2u Ed = Z2d - Z3d + Z3u - Z2u

The energy flow Epv2d from the electrical energy generation device PV is always the minimum of two energy flows, namely the total energy flow Epv generated by the electrical energy generation device PV and the energy flow Ed required by the electrical consumer group D.

Shown as a formula: Epv2d = min (Epv ; Ed)

From the formula Epv = Epv2g + Epv2b + Epv2d follows with Epv2g = Z1 u - Z2u and Epv2b + Epv2d = Z2d - Z1d and Epv = Z2d - Z1d + Z1 u - Z2u

Epv2d=min (Z2d-Z1d+Z1u-Z2u; Z2d-Z3d+Z3u-Z2u) The energy flows Ebe flowing from the electrical energy store B result in meter notation as Ebe=Z3u.

The energy flows Eg2re flowing from the electrical transmission network G into the reserve unit RE result in meter notation as Eg2re=Z1d

All terms from the consideration according to the law of conservation of energy:

E = Ed - Epv2d - Ebe - Eg2re can now be resolved in counter notation:

E=Z2d-Z3d+Z3u-Z2u-min(Z2d-Z1 d+Z1 u-Z2u;Z2d-Z3d+Z3u-Z2u)-Z3u-Z1 d The underlined terms Z3u cancel, leaving the determination of the transfer energy flux E in numerator notation:

E = Z2d - Z3d - Z2u - min (Z2d - Z1d + Z1u - Z2u ; Z2d - Z3d + Z3u - Z2u) - Z1d

In order to determine the transfer energy flow E in a way that is suitable for billing purposes, six electrical counter devices would be necessary. Providing all of these as calibrated metering devices is not economical. On the part of the control of the overall system, there is the premise that the electrical energy generated by the electrical energy generating device PV primarily covers the energy requirements of the electrical consumer group D. The keyword here is the self-consumption optimization that is usually sought for economic reasons in such reserve units. Under this premise and considering various case distinctions regarding the ratio of Epv to Ed, the formula for determining the transfer energy flow is simplified considerably. 1. Case group Epv <= Ed:

Electrical energy is not generated in the reserve unit in such a way as to cover the existing power requirements of electrical consumer group D. This means that only the first term for Epv remains from the minimum function:

E = Z2d - Z3d - Z2u - (Z2d - Zld + Z1u - Z2u) - Zld

The underlined terms cancel and it remains:

E = - Z3d - Z1u and the amount of transfer energy flow is given as E = Z3d + Z1u 1. Case group special case Epv=0 -> Epv2d=0:

The electrical energy generating device does not generate any electrical energy and can therefore also not contribute to covering the electrical power requirement of the electrical consumer group; the energy flow Epv2d is equal to zero. This simplifies the consideration according to the law of conservation of energy as follows:

E = Ed- Ebe - Eg2re in numerator notation: E = Z2d - Z3d + Z3u - Z2u - Z3u - Z1d

Term Z3u cancels out: E = Z2d - Z3d - Z2u - Z1d

If Epv2d=0 it follows inevitably that Z1d=Z2d and Z1u=Z2u This simplifies E = -Z3d - Z1u and the magnitude of the transfer energy flow is found to be E = Z3d + Z1u

This corresponds to the result of the first case group. Consequently, Epv < Ed with the extreme case Epv=0 is uniformly considered as the first case group.

2. Case group Epv>Ed, i.e. Epv2d=Ed:

The electrical energy generating device PV generates so much energy that the entire power requirement of the electrical consumer group D ge can be covered. This simplifies the consideration according to the law of conservation of energy as follows:

E = Ed - Ed - Ebe - Eg2re E = -Ebe - Eg2re E = -Z3u - Z1d as absolute value: E = Z3u + Z1d

With this consideration, so-called system-maintaining energy flows are included in the determined transfer energy flow E. However, these falsify the billing-relevant result and are therefore extracted via subsequent procedural steps. System-maintaining energy flows Esys occur with characteristic measured values when, for example, the electrical energy store B is empty and the electrical energy generating device PV currently and for the foreseeable future does not generate any electrical energy, so that there is a risk of an undesirable deep discharge of the storage system. The electrical energy store B is then charged at least to a minimum state of charge using energy from the electrical transmission network G. Further examples of system-maintaining energy flows Esys are explained in the subclaims.

FIG. 3a shows the remaining energy flows between the system components from FIGS. 1 and 2 for the first case group Epv<=Ed with the further boundary condition of a discharging electrical energy storage device B. At least if the electrical energy storage device B is designed as a battery, it can only be charged or discharged. Simultaneous discharging and charging are not possible for electrophysical reasons. For such a discharged electrical energy storage device B, it follows inevitably that no energy can flow in the direction of electrical energy storage device B—Z3d must therefore be zero.

From this it follows for E = Z3d + Z1u that E = Z1u. The transfer energy flow E to be determined is therefore available as the sole measured value Z1u of the first electrical counter device Z1. Since this usually delivers calibrated measured values at the grid connection point NAP, the transfer energy flow E can be determined in this way for the first case group with the boundary condition of a discharging electrical energy storage device B in a way that is suitable for billing.

Figure 3b shows the remaining energy flows between the system components from Figures 1 and 2 for a case group Epv<=Ed with the boundary condition of a charging electrical energy storage device B. For such a charging electrical energy storage device B it follows that no energy flow occurs the electrical energy store B can be done out. Z1u must therefore be zero.

From this it follows for E = Z3d + Z1u that E = Z3d. The transfer energy flow E to be determined is therefore the only measured value Z3d of the second further electrical counter device Z3 before. If this delivers calibrated measured values, the transfer energy flow E can be determined in this way for the first case group with the boundary condition of a charging electrical energy store B in a way that is suitable for billing.

Figure 4a shows the energy flows between the system components from Figures 1 and 2 for the first case group Epv=0<Ed for the special case Epv=0 with the boundary condition of a discharging electrical energy store B.

As shown above, E = Z3d + Z1u also applies here for the transfer energy flow. Because the electrical energy store B is exclusively discharged, Z3d is equal to zero and the transfer energy flow E to be determined results as the sole measured value Z1u from the calibrated first electrical counter device Z1.

FIG. 4b shows the remaining energy flows between the system components from FIGS. 1 and 2 for the first case group Epv=0<Ed for the special case Epv=0 with the boundary condition of a charging electrical energy store B. As shown above, the same applies here for the transfer energy flow E = Z3d + Z1u. Because the electrical energy storage device B is exclusively charged, Z1u is equal to zero and the transfer energy flow E to be determined results as the sole measured value Z3d from the preferably calibrated second further electrical meter device Z3.

Figure 5a shows the remaining energy flows between the system components from Figures 1 and 2 for the second case group Epv>Ed with the boundary condition of a discharging electrical energy store B. No energy is therefore required from the electrical transmission network G to meet the electrical power requirement of the to cover electrical consumer group D - thus Eg2d=0. As was derived above, the transfer energy flow to be determined results from E=Z3u+Z1d, with no energy flow in the opposite direction being able to flow from the electrical transmission network G into the reserve unit because of the discharging electrical energy store B. Consequently, Z1d is equal to zero and the transfer energy flow to be determined is E = Z3u. Figure 5b shows the remaining energy flows between the system components from Figures 1 and 2 for the second case group Epv>Ed with the boundary condition of a charging electrical energy store B. In this scenario, no energy is required from the electrical transmission network G to charge the electrical To cover the power requirement of the electrical consumer group D - thus Eg2d=0. As was derived above, the transfer energy flow to be determined results from E=Z3u+Z1d, with no energy flow in the opposite direction being able to flow from the electrical energy storage device B into the electrical transmission grid G because of the charging electrical energy storage device B. Consequently, Z3u is equal to zero and the transfer energy flow to be determined is E = Z1d.

As a result, the method described above makes it possible to find a meter notation based on a consideration in accordance with the law of conservation of energy, which, with differentiation using case groups combined with boundary conditions, becomes so simple that the transfer energy flow to be determined is available as a measured value from a single electrical meter device.

This goal can also be achieved for a different arrangement of the further electrical counter devices Z2 and Z3 within the reserve unit. It is also conceivable that more than a first and a second further electrical counter device Z2 and Z3 are used. Ultimately, the appropriate arrangement of the measuring points within the reserve unit in combination with suitable case groups and the associated boundary conditions are decisive in order to achieve the desired result of this procedure.

If this result is available for a defined constellation of electrical metering devices within a reserve unit RE, then this result is used below to determine the transfer energy flows in continuous operation of the reserve unit RE. It is therefore only necessary to carry out the method previously explained using an example once to the desired result. Thereafter, the sustainable benefit is drawn from the use of this method result, the transfer energy flows E between an electrical transmission network G and a reserve unit RE to be determined in a simple manner in a way that is suitable for billing.

Figure 6 shows a flow chart to illustrate such a use of the method results for determining the transfer energy flow E.

First, the absolute value ratio between the total generated energy flow Epv of the electrical energy generating device PV and the energy flow Ed required at the same time for the electrical consumer group D in the reserve unit RE is determined. There is either the first case group with the ratio Epv <= Ed including the special case Epv=0 or the second case group with Epv>Ed. Then, in a further decision, it is determined whether the boundary condition of a discharging electrical storage device Eb+ or the boundary condition of a charging electrical storage device Eb− is present. Depending on which boundary condition is combined with the respective case group, the transfer energy flow E to be determined is determined in the form of a transfer energy flow Eh flowing out of the reserve unit RE or in the form of a transfer energy flow Er flowing into the reserve unit RE. This method algorithm uses the previously obtained method results in order to ensure a billable determination of the transfer energy flows E in continuous operation of the reserve unit. The algorithm shown here looks correspondingly different for the use of other method results likewise obtained according to the invention. Such use of the method results is preferably implemented in a control unit SE, as shown schematically in FIGS. 1 to 5b. The control unit SE is designed and set up to use the method results described as part of an implemented method. However, it is also conceivable for the control device embodied in hardware and software to be fully or partially implemented in a centralized manner and thus determine the transfer energy flows for a large number of reserve units RE at different locations. Reference list:

RE reserve unit

D electrical consumer group

ESS electrical energy storage system

B electrical energy storage of the ESS

SE control unit of the electrical energy storage system ESS

PV electric power generation device

NAP grid connection point of the reserve unit

G electrical transmission network

Z1 first electrical counter device

Z2 first additional electrical counter device

Z3 second additional electrical counter device

E transfer energy flow

It transfers energy flow from the transmission network to the reserve unit

Eh Transfer- energy flow from the reserve unit to the transmission grid

Ed absorption energy flow of electrical consumer group D

Eg2re mains energy flow from the transmission network G to the reserve unit RE

Eg2d share of grid energy flow for consumer group D

Epv2d producer-to-consumer energy flow of the energy generating device

Epv total producer energy flow of the energy generating device PV

Epv2g producer energy flow as feed-in into the transmission grid G

Ebe storage energy flow from the electrical energy storage device B

Eb2d store-to-consumer energy flow from energy store B

Esy's system-preserving intake energy flow

Claims

Patent Claims:

1. Method for determining an electrical transfer energy flow (E) into or out of a reserve unit (RE), the reserve unit (RE) comprising:

• an electrical consumer group (D),

• an electrical energy storage system (ESS) with an electrical energy store (B) and

• an electrical energy generating device (PV), wherein the reserve unit (RE) is defined via a grid connection point (NAP) and is connected via this to an electrical transmission grid (G), with the grid connection point (NAP) having a first electrical meter device (Z1) is intended to determine a measured value Z1d as a network energy flow from the transmission network (G) into the reserve unit (RE) and to determine a measured value Z1u as a network energy flow from the reserve unit out into the electrical transmission network (G), the method is characterized by the following steps:

• Determination of a recording energy flow (Ed) comprising the electrical consumer group (D) in a defined time interval,

• Determination of a network energy flow (Eg2re) from the electrical transmission network (G) to the reserve unit (RE) in the defined time interval,

• Determining a generator energy flow of the electrical energy generation device (PV) in the defined time interval,

• Determining a storage energy flow (Ebe) between the electrical energy storage (B) of the electrical energy storage system (ESS) and the electrical consumer group (D) and / or the electrical transmission system (G) in the defined time interval and

• Determination of the transfer energy flow (E) in the defined time interval based on the law of conservation of energy, with further electrical energy flows within the reserve unit (RE) between at least two assemblies selected from: the energy storage system (ESS), - the power generating device (PV) and

- The electrical consumer group (D) are determined by further electrical metering devices (Z2, Z3) in such a way that in a case distinction selected from the two case groups:

- The energy generating device (PV) generates more electrical power than the electrical consumer group (D) requires and

- The energy generating device (PV) generates no or the same amount or less electrical power than the electrical consumer group (D) requires combined with a boundary condition selected from:

- The electrical energy storage device (B) charges and

- The electrical energy storage device (B) discharges, the transfer energy flow (E) for the selected case group with the combined boundary condition as a measured value of a single one of the first or one of the other electrical counter devices (Z1, Z2, Z3) is present.

2. The method according to claim 1, characterized in that

• the determination of the generator energy flow as a determination of a generator-to-consumer energy flow (Epv2d) from the electrical energy generating device (PV) into the electrical consumer group (D) is carried out in the defined time interval.

3. The method according to claim 1 or 2, characterized in that

• the determination of the intake energy flow (Ed) is carried out as a determination of the intake energy flow (Ed) of the electrical consumer group (D) in the defined time interval.

4. The method according to claim 3 referring back to 2, characterized in that the transfer energy flow (E) is determined using the law of energy conservation using the formula: E=(Ed−Epv2d−Ebe−Eg2re).

5. The method according to claim 4, characterized in that the method step of determining the generator energy flow (Epv2d) from the electrical energy generating device (PV) to the electrical consumer group (D) in the defined time interval with a first further electrical counter device (Z2) with a measured value Z2d for an energy flow in the direction of the electrical consumer group (D) and/or in the direction of the electrical energy storage system (ESS) and with a measured value Z2u for an energy flow oriented in the opposite direction, with the electrical energy generating device ( PV) is connected between the first electrical meter device (Z1) and the first additional electrical meter device (Z2) in such a way that electrical current generated with the electrical energy generating device (PV) flows both via the first electrical meter device (Z1) into the electrical transmission network (G) can feed t, as well as via the first additional counter device (Z2) to the electrical consumer group (D) and/or to the electrical energy storage system (ESS), with the generator energy flow (Epv2d) always being the smaller energy flow of the two energy flows:

- absorption energy flow (Ed) and

- total generator energy flow (Epv) is determined.

6. The method according to claim 5, characterized in that a total generator energy flow (Epv) is determined by forming the difference between the energy flow measured value Z2d of the first further counter device (Z2) and the measured value Z1d of the network energy flow (Eg2re). and the following difference is added to it: the measured value Z2u is subtracted from the measured value Z1u as the network energy flow (Eg2re) from the reserve unit into the electrical transmission network.

7. The method according to claim 5 or 6, characterized in that a store-to-consumer energy flow (Eb2d) from the electrical energy store (B) of the electrical energy storage system (ESS) for electrical consumption user group (D) is carried out in the defined time interval by forming a difference as follows: the energy flow Z2d measured with the first additional electrical metering device (Z2) is subtracted from the ascertained intake energy flow (Ed), provided this formed difference is greater than zero and if the difference formed is less than zero, the store-to-consumer energy flow (Eb2d) is set equal to zero.

8. The method according to any one of claims 1 to 7, characterized in that an energy flow into the electrical energy store (B) with a measured value Z3d and the storage energy flow from the electrical energy store (B) with a measured value Z3u using the electrical Energy store (B) upstream second further counter device (Z3) are determined.

9. The method according to claim 8, characterized in that the two case groups relate to a size comparison of the intake energy flow (Ed) to the total generator energy flow (Epv) via the measured values of the first counter device (Z1) and via the measured values of the second additional Counter device (Z3) can be determined as follows:

For size comparison, Epv is Z1u-Z1d and Ed is Z3u-Z3d

10. The method according to claim 8 or 9, characterized in that for the case group the total producer energy flow (Epv) is greater than the receiving energy flow (Ed):

- under the boundary condition of a charging electrical energy store (B), i.e. Z3d>0, the transfer energy flow (E) is determined as the measured value Z1d,

- under the boundary condition of a discharging electrical energy store (B), i.e. Z3u>0, the transfer energy flow (E) is determined as the measured value Z3u and for the case group the total generator energy flow (Epv) is less than or equal to that Receiving energy flux (Ed), including the case when the total producer energy flux (Epv) is 0: - under the boundary condition of a charging electrical energy store (B), i.e. Z3d>0, the transfer energy flow (E) is determined as the measured value Z3d,

- Under the boundary condition of a discharging electrical energy store (B), ie Z3u>0, the transfer energy flow (E) is determined as the measured value Z1u.

11 . Use of the results of a method according to one of the preceding claims, characterized in that to determine transfer energy flows (E) between an electrical transmission network (G) and a procedural reserve unit (RE), the measured values of at least one electrical meter device (Z1, 12 , 13) can be determined, which have the transfer energy flow (E) to be determined under procedurally defined case groups and boundary conditions.

12. Use according to claim 11, characterized in that system-retaining recording energy flows (Esys) in the electrical energy storage system (ESS) that are not included in a specific recording energy flow (Ed) of the electrical consumer group (D). , are determined and balanced against the determined electrical transfer energy flow (E).

13. Use according to claim 12, characterized in that when determining not included in the intake energy flow (Ed), system-maintaining intake energy flows (Esys) characteristics in the specific transfer energy flow (E), caused by one or more of the system-maintaining intake Energy flows (Esys) are used to correct the determined transfer energy flow (E).

14. Use according to claim 12 or 13, characterized in that the system-maintaining energy flows (Esys) are selected from the group comprising:

• an energy flow caused by a standby power consumption of an inverter installed in an energy storage system (ESS), if an electrical energy store (B) of the energy storage system (ESS) is empty and the standby power consumption cannot be guaranteed,

• an energy flow caused by a trickle charge of the electrical energy storage system (ESS) belonging to the electrical energy storage device (B) and

• an energy flow caused by a cyclical full charging of the electrical energy store (B) belonging to the electrical energy storage system (ESS).

15. Use of the results of a method according to one of Claims 1 to 10 or according to a use according to Claims 11 to 14, characterized in that a determination of the transfer energy flow (E) is carried out in real time during defined time intervals in the range from 10 seconds to 15 minutes, preferably in the range from 30 seconds to 10 minutes and particularly preferably in the range from one minute to five minutes.

16. Use of the results of a method according to any one of claims 1 to 10 or according to a use according to claim 11 to 14, characterized in that a determination of the transfer energy flow (E) subsequently using stored data sets during defined time intervals in the range of 10 seconds to 15 minutes, preferably in the range from 30 seconds to 10 minutes and particularly preferably in the range from one minute to five minutes.

17. Use according to one of the preceding use claims 11 to 16 or use of the results of a method according to any one of claims 1 to 10, characterized in that a determination of the Trans fer energy flow (E) in a control unit (SE) of the electrical energy - Storage System (ESS) is performed.

18. Use according to any one of the preceding use claims 11 to 16 or use of the results of a method according to any one of Claims 1 to 10, that a determination of the transfer energy flow (E) in an outside of the reserve unit (RE) arranged evaluation unit is performed.

19. A control system designed and set up to carry out a method according to one of claims 1 to 10 or a control system designed and set up to use the results of the method according to one of use claims 11 to 18.