DH-500 Distribution system operator’s imbalance settlement
- 1 Initial data for balance settlement
- 2 Virtual production units
- 3 Imbalance settlement calculations and calculated data
- 4 Information exchange in imbalance settlement
- 5 Data reported to eSett
- 6 Supplier’s imbalance settlement data
- 7 Distribution system operator’s imbalance settlement data
- 8 Imbalance settlement calculations outside the balance window
This chapter describes the DSO’s imbalance settlement calculations performed in Datahub and imbalance settlement data notifications to eSett and market parties. Datahub handles imbalance settlement reporting of all data to eSett on behalf of the DSO. Datahub provides a user interface for maintenance of so-called structural information. The user interface enables the parties to maintain information that has no defined messaging processes. Datahub also sends the DSO data about metering grid area imbalance and MGA exchange confirmations calculated by eSett.
The DSO is responsible for reporting settlement data required to calculate the imbalance settlement described in this section to Datahub in accordance with the agreed rules and deadlines. Datahub is responsible for performing the imbalance settlement calculations and sending these to eSett in compliance with the rules of the Nordic balance settlement model (NBS). The rules of the NBS model are described in a handbook released by eSett. Imbalance settlement data can also be retrieved from Datahub by parties entitled to this data.
The most important tasks in the daily imbalance settlement process are executing the imbalance settlement calculations based on structural information and metering data, and information exchange of balance settlement data. Imbalance settlement calculations depend on DH-120, DH-200, DH-300 and DH-400 processes, and on structural information, which is maintained via the user interface. The information, which is handled in balance settlement and exchanged between parties, is described in more detail later in this chapter.
Initial data for balance settlement
Imbalance settlement data consists of structural information and metering/time series data. Structural information defines to which party’s balance and to which metering grid area each metering point’s metering data (metered consumption or production) is calculated in balance settlement calculations executed by Datahub.
According to the Nordic Balance Settlement model, an imbalance statement by a DSO is calculated by metering grid area. DSOs can divide their grids into one or more metering grid areas. However, DSOs usually have only one metering grid area. The figure below presents the data used as the basis for imbalance settlement calculations in Datahub. With the exception of electricity sales agreement information, the DSO is responsible for maintaining this data. Technically, however, the Datahub operator will maintain metering grid area data, because this data significantly and widely affects other processes and data in Datahub, for example, imbalance settlement calculations and accounting point data. The goal of this procedure is to ensure that all necessary changes, like terminating and adding metering grid areas, are done in a controlled manner taking all viewpoints into consideration.
Relations marked with blue have a time when they are valid. This means that for example the loss supplier of a metering grid area may change with time and the system must be able to handle these changes so that the history data is maintained. When interpreting the figure, one must take into account that for some of these relations only one relation at a time can be valid, even though the relation is marked with “1..*”. Accurate relation definitions can be found in the Datahub data standard. Validity of the relations related to balance information is based on the validity of the balance information. Datahub also handles market balance area information, although Finland has only one market balance area. This ensures that Datahub supports the structure of the electricity market for possible future demands.
The foundation for imbalance settlement calculations is the metering data from the metering points: accounting points, exchange points and production units. Metering points always belong to one metering grid area at a time. However, the system must be able to handle situations where metering points move to another metering grid area at a defined time. These situations may occur when metering grid areas unite or divide into a larger number of metering grid areas. These situations and their management are described in more detail in section Structural changes to a metering grid area. Datahub must include the possibility to define to which market balance area each metering grid area belongs to at a given time so that it supports the general structure of the electricity market.
The DSO maintains accounting point information by means of the accounting point information maintenance events (DH-120). The exchange point and production unit information is maintained via the Datahub interface. This information must be created via the interface before the metering data for the metering points in question is reported. The DSO also maintains information about the production unit supplier. The metering data of all metering points is reported in accordance with event DH-211 reporting metering data. The DSO must also use the interface to maintain information on the suppliers responsible for the open supplier and loss supplier roles for the metering grid area at a given time (imbalance). In the user interface, there is a report for DSOs where the structural information depicted above is available, excluding the accounting point specific settlement data,
Using the user interface, the DSO may use delegation to authorize other parties to exchange point and production unit metering data. For exchange points, only the DSO of the metered data responsible MGA can issue the delegation. In that case, the metering data of these metering points will automatically be forwarded to the authorized parties. By default, exchange point metering data will always be forwarded also to the DSO of the exchange point’s other metering grid area when both metering grid areas of the exchange point do not belong to the same DSO. Information about the electric station and its field, to which an exchange point is connected, is available in Datahub to make information processing easier in the market parties’ own processes and in Datahub.
Accounting point metering data is linked to a supplier in balance settlement calculations using so called balance information. If an accounting point does not have a valid balance information, the possible production and consumption of the accounting point are calculated into the losses of the metering grid area, in other words to the balance of the DSO. Most of the time the validity of the balance information is similar to the start and end dates of the accounting point’s sales agreement reported by the supplier. However, balance information may change when sales agreements are cancelled or retroactively corrected, or during connection and disconnection processes initiated by the supplier. Balance information changes related to cancelling sales agreements and error corrections are described in section Retroactive error correction. If a supplier requests disconnection of an accounting point within agreed time limits, but the DSO for some reason cannot disconnect the accounting point, the consumption/production of the accounting point is calculated into the losses of the metering grid area according to the industry convention. Because of this, the balance responsibility is transferred to the DSO (supplier’s balance information is updated) starting the day after the requested disconnection date in the supplier’s disconnection request. Balance responsibility is transferred back to the supplier (new balance information is created) based on the connection time reported by the DSO.
Virtual production units
Small-scale production per metering grid area and supplier, i.e., production related to an accounting point with a type production, is handled in NBS by creating a virtual production unit. The small-scale production total per metering grid are and supplier is calculated into the production of the virtual production unit. Because of this, there must always be a virtual production unit per supplier, metering grid area and NBS production type in the system when a supplier has balance information for an accounting point with the accounting point type ‘production’. Virtual production units are handled in Datahub in such a manner that adding, removing or updating the validity of virtual production units does not require specific actions from the user.
Virtual production units are handled in the NBS model as any other production units. Thus, virtual production units must have identification, name, NBS production type and capacity recorded in the system. Maintaining capacity, for example, by adding the powers of production devices is not worthwhile, because this might mean calculating new capacity daily. Because of this, it must be possible to define the capacity with a predetermined value. The name of the virtual production unit is generated automatically, for example, based on identifications of metering grid area and supplier and the production type. The system creates an identification for the virtual production unit based on the identification system which is in use at the time of creation. The system updates the validity of the relation between virtual production unit and supplier so that the relation is valid exactly when the supplier has at least one balance information for an accounting point in the metering grid area and the production type of the accounting point corresponds the NBS production type of the virtual production unit. The validity in question may consist of one or more time periods.
The production type of the virtual production unit depends on the production devices reported for the accounting point. NBS production types differ from the production types defined for Datahub production devices. The relations between the production types are presented in the table below. If the production accounting point has no reported production devices or the production accounting point has several production devices with different production types, the production type of the virtual production unit is ‘other production’. If the production accounting point has one or more production devices of the same type, the NBS production type of the production unit will be determined based on the production devices of the accounting point according to the table.
Cross-tabulation of the site’s production type with NBS production types:
Accounting point production type | NBS production type |
Solar power | Solar |
Gas turbine | Thermal |
Combined production | Thermal |
Wave power | Other production |
Bioenergy | Other production |
Diesel engine | Other production |
Other production | Other production |
Wind onshore | Wind onshore |
Wind offshore | Wind offshore |
Hydropower | Hydro |
Nuclear power | Nuclear |
Energy storage | Energy storage |
The table below presents a condensed version of the rules according to which the system generates a new virtual production unit or updates its information.
Defining the data of a virtual production unit:
Attribute/relation of the virtual production unit | Basis for determination |
Production unit – Metering time series | Metering time series of the virtual production unit is the resulting time series ‘Supplier’s small-scale production’ in the balance settlement. |
Capacity | Predetermined value, which is used for all new virtual production units. |
Name | Name generated by the system, such as <supplier_id>_ <metering grid area id>_<NBS production type>. |
(NBS) Production type | Determined by the system based on production types of the accounting point’s production devices. |
Production unit identification | The system generates a new identification according to the requirements of the data standard. |
Production unit – Metering grid area | Metering grid area for the virtual production unit. Validity is not updated, instead a new virtual production unit is created if necessary. |
Production unit – Supplier | Validity is determined based on the validity of balance information so that the relation is always valid when the supplier has at least one balance information for an accounting point, which is related to a corresponding metering grid area and which has a production type that corresponds the production type of the production unit. The relation may have several time periods, if necessary. |
Imbalance settlement calculations and calculated data
Datahub calculates the imbalance settlement time series (imbalance settlement resulting time series) based on structural information and metering data until the closing of the balance window. The figure below presents the general structure of imbalance settlement time series based on NBS model and from the Datahub point of view. The actual imbalance settlement time series are described later in this chapter.
The imbalance settlement time series are the basis of imbalance settlement performed by eSett. In Datahub, the balance settlement type defines the purpose of the imbalance settlement time series in balance settlement. The imbalance settlement method indicates whether the time series data is based on data that is metered or specified in some other manner, in other words, profiled data. All metering data related to an accounting point with a metering method of ‘reading metering’ or ‘unmetered’ is profiled metering data in Datahub. In practice, the metering method of an accounting point may change several times, and these changes and their validity must be taken into account in balance settlement calculations. For example, consumption is calculated into supplier’s profiled sum delivery only from time periods when the metering method of the accounting point is ‘reading metering’ or ‘unmetered’.
Not all balance settlement method and type combinations are in use. For example, the NBS model allows for both metered and profiled (grid) losses, although only metered losses are used in Finland. Profiled balance settlement data is used only for sum deliveries and production units’ own consumption in Finland. The metering method of the accounting point defines the balance settlement method the consumption/production of the accounting point is calculated into.
The balance settlement connection is Datahub’s equivalent to the MEC (Market Entity Connection) defined by eSett. Datahub’s balance settlement connection is a construct that defines balance settlement method and type related to imbalance settlement time series, as well as connects time series to market parties and on behalf of production data to (virtual or actual) production units. Datahub maintains balance settlement connections automatically based on initial data for balance settlement. Although there can be more than one balance settlement connection in Datahub with the same combination of balance settlement type, balance settlement method, supplier, metering grid area and production unit, only one of them can be valid at a time. The balance settlement structural information eSett reports to Datahub is mostly based on balance settlement connections.
Imbalance settlement is done per metering grid area and per supplier, i.e., there must be a supplier for all production and consumption. All consumption and production without a defined supplier is calculated, according to calculation rules, into the metering grid losses and to the balance of the metering grid area loss supplier. Only metering grid area sum level imbalance settlement time series do not have a related supplier. These time series are not used in imbalance settlement or reported to eSett, they are only used for statistical and analytical purposes.
Out of the imbalance settlement time series in Datahub, metering grid area imbalances and MGA exchange confirmations are calculated in eSett’s system. Imbalance is a tool for handling situations where, due to various rounding, calculation and information exchange errors, the metering grid area’s exchange point sum does not match the sum of metering grid area’s productions, suppliers’ deliveries and losses. In these cases the calculated imbalance is recorded as a delivery of the metering grid area imbalance open supplier. Imbalance is calculated as the sum of the calculations 1–7 in the table below, considering the signs. Because the metering grid area losses (calculation 7) is calculated as the sum of calculations 1–6, the calculated imbalance should always be zero under normal circumstances. eSett separately reports MGA imbalance as an intermediate report from the open balance window and as a final report from the closed day of the balance window.
According to the NBS rules, Datahub classifies the supplier and metering grid area specific sum information it reports according to balance settlement type and method. The table below presents the metering grid area-specific sum calculations calculated by Datahub, which are used in Finnish imbalance settlement. The data with gray background is reported to eSett for imbalance settlement. The principle in calculating the metering grid area losses is that the losses are calculated based on information that is reported to eSett, not based on metering grid area sum calculations. The losses are calculated, for example, based on individual exchange point sums instead of metering grid area total exchange point sum to avoid possible rounding errors. Rounding errors could cause unnecessary imbalance in eSett calculations.
With the transition to 15-minute imbalance settlement, Datahub calculates the aggregated balance settlement data in 15-minute intervals. For hourly measurements, the balance settlement calculation first aggregates the hourly series into their own sum series. These hourly sum series are then divided by four and added to the 15-minute sum series.
Metering grid area-specific sum calculations calculated by Datahub:
# | Data to be calculated | Description |
1 | Supplier’s metered sum delivery | The supplier’s calculated sum, in accordance with the official imbalance settlement period, of metering time series of fifteen minute and hourly-metered consumption accounting points in the metering grid area. |
2 | Supplier’s profiled sum delivery | The supplier’s calculated sum, in accordance with the official imbalance settlement period, of metering time series of profiled (reading metered or unmetered) consumption accounting points in the metering grid area. |
3 | Supplier’s small-scale production sum (per production type) | The supplier’s calculated sum, in accordance with the official imbalance settlement period, of metering time series of small-scale production accounting points in the metering grid area, per production type |
4 | Supplier’s metered own consumption sum | The supplier’s calculated sum, in accordance with the official imbalance settlement period, of production unit’s own consumption accounting points’ metered metering time series in the metering grid area. |
5 | Supplier’s profiled own consumption sum | The supplier’s calculated sum, in accordance with the official imbalance settlement period, of production unit’s own consumption accounting points’ profiled metering time series in the metering grid area. |
6 | Exchange point sum | The exchange point sum between two metering grid areas calculated from exchange point metering. |
7 | Metering grid area losses | Calculated based on sections 1–6 production unit productions using formula
|
8 | Supplier’s total small-scale production sum | Sum of supplier’s small-scale production sums in section 3. |
9 | Metered sum delivery of the metering grid area | Sum of metering grid area’s sum deliveries in section 1. |
10 | Profiled sum delivery of the metering grid area | Sum of metering grid area’s sum deliveries in section 2. |
11 | Small-scale production sum of the metering grid area (per production type) | Sum of metering grid area’s small-scale production sums in section 3. |
12 | Metered own consumption sum of the metering grid area | Sum of metering grid area’s own consumption sums in section 4. |
13 | Profiled own consumption sum of the metering grid area | Sum of metering grid area’s own consumption sums in section 5. |
14 | Production unit sum of the metering grid area (per production type) | Sum of all production unit meterings in the metering grid area, per production type. |
15 | Total exchange point sum of the metering grid area | Sum of exchange point sums in section 6, which are related to the metering grid area. |
16 | Total small-scale production sum of the metering grid area | Sum of metering grid area’s small-scale production sums in section 12. |
17 | Total production unit sum of the metering grid area | Sum of metering grid area’s production unit sums in section 15. |
The chart below presents a diagram of how the calculations described above are dependent on each other and on individual metering time series.
Information exchange in imbalance settlement
In addition to being used in balance settlement calculations, balance settlement structural information and time series information calculated by Datahub are exchanged between the parties in Datahub. Datahub reports the updated structural information and the calculated imbalance settlement data to eSett daily. eSett calculates the imbalances of metering grid areas based on information reported by Datahub and reports the imbalances to Datahub. Finally, Datahub reports the imbalance settlement data it has calculated and the imbalances of metering grid areas to the market parties according to their rights. In addition to the above-described daily process (DH-510), the parties can specifically request imbalance settlement data from Datahub using DH-520 events.
The diagram below presents the information exchange for imbalance settlement (Datahub events).
Data reported to eSett
This section describes how imbalance settlement data is reported from Datahub to eSett using the current interface specifications (available at NMEG ). Thus, the data exchanges presented below do not apply to DSOs, and Datahub reports this information on behalf of the DSOs. However, the DSO must for its part maintain the data described in section Initial data for balance settlement in Datahub so that this data can be compiled and reported to eSett. Datahub and eSett can also agree on information exchange that is based on interface specifications other than those outlined above.
Structural information
Datahub reports structural information to eSett separately before the metering data can be reported. Reporting structural information is mainly based on balance settlement connections described in chapter Imbalance settlement calculations and calculated data. Structural information is reported to eSett on a supplier or metering grid area level; only production unit information is reported for individual metering points. Structural information includes information about which supplier operates in a certain MGA. For example, when a new supplier is registered in Datahub, this information is reported to eSett. Technically speaking, also the small-scale production sum is processed as a so-called virtual production unit and it is separately created for each unique supplier, metering grid area and production type combination.
Datahub reports the following structural information to eSett for the DSO’s imbalance settlement:
Data | NBS Information exchange document |
Metering grid area data | Area Specification Document |
Exchange point connections (MGA–MGA relation) | Area Specification Document |
Supplier operating in the MGA | Party Master Data Document |
Production unit data | Resource Object Master Data Document |
Exchange point connections is information about which two metering grid areas have transmission between them, i.e., which two metering grid areas have at least one exchange point. For the supplier operating in the MGA, Datahub includes the following information in its notification to eSett: MGA, consumption type (BusinessTypeCode), imbalance settlement method (SettlementMethodCode) and validity data. Each balance settlement type/settlement method combination for each supplier must be reported as separate data to eSett in accordance with the table below.
Time series data
Datahub reports the below-mentioned time series to eSett on a supplier- and metering grid area-specific basis:
Data | NBS Information exchange document | BusinessType | SettlementMethodCode (Settlement method) |
Metered sum delivery | Aggregated Data per MGA for Settlement Responsible from MDA | Consumption (A04) | Non profiled |
Profiled sum delivery | Aggregated Data per MGA for Settlement Responsible from MDA | Consumption (A04) | Profiled |
Metered own consumption sum | Aggregated Data per MGA for Settlement Responsible from MDA | Production Units own consumption (B36) | Non profiled |
Profiled own consumption sum | Aggregated Data per MGA for Settlement Responsible from MDA | Production Units own consumption (B36) | Profiled |
MGA losses (must be allocated to a single supplier) | Aggregated Data per MGA for Settlement Responsible from MDA | Losses (A15) | Non profiled |
In addition to the above, Datahub reports to eSett the production data for individual production units (PU), supplier-specific small-scale production sums by MGA and exchange point sums between grids. Datahub creates a virtual production unit (PU) for the supplier’s MGA small-scale production sum, for which the data is reported. When the metering grid area loss calculation produces negative values, for example, due to missing metering data, Datahub will report negative values as a part of the production of the metering grid area’s loss supplier’s virtual production unit with the production type ‘other production’. This is the course of action because eSett does not allow negative values for consumption (or production). The information exchange documents that Datahub can use to report this information to eSett are listed below.
Data | NBS Information exchange document | MeteringPointTypeCode |
Supplier’s small-scale production sum | Validated data for Aggregator from MDR | Production |
Production unit’s production | Validated data for Aggregator from MDR | Production |
Exchange point sum | Aggregated Data per neighbouring grid | Exchange |
Supplier’s imbalance settlement data
Datahub calculates imbalance settlement time series data for the supplier and the MGA. The diagram below presents the supplier’s MGA-specific imbalance settlement data. The new and changed imbalance settlement data for the duration of the balance window and for the latest day locked in the balance settlement is reported to suppliers on a daily basis. In addition to the notification, the suppliers can also retrieve this data separately from Datahub. In the figure, supplier’s small-scale production refers to small-scale production per production type, and total small-scale production sum refers to the sum of all small-scale productions. Not every supplier has all information. For example, the metering grid area losses are reported only to the supplier who is the loss supplier for the metering grid area.
Distribution system operator’s imbalance settlement data
The DSO has the right to both the above-mentioned supplier’s imbalance settlement data and the MGA imbalance settlement data. The new and changed imbalance settlement data calculated by Datahub is reported to the DSOs on a daily basis until the first day outside the balance window. In addition to the notification, the DSOs can also retrieve this data separately from Datahub. Small-scale production for metering grid areas is also reported separately both per production type and as sum of all productions.
In addition to balance settlement data, Datahub reports to the DSO when a sales agreement of an accounting point is terminated so that the DSO can disconnect the accounting point. Datahub also reports separately to DSOs if an accounting point is without a supplier and does not have a reported disconnection. In addition to the previously mentioned, Datahub provides an information request event that DSOs can use to get accounting point specific consumption/production, which are calculated into the DSO’s losses.
Imbalance settlement calculations outside the balance window
Imbalance settlement calculations are primarily calculated in Datahub for the needs of the official imbalance settlement performed by eSett. Imbalance settlement calculations do however have another use in addition to official imbalance settlement. For example, metering grid area losses are a significant cost to a grid company, and the exact amount of losses is also monitored by grid companies outside the balance window. Datahub is the primary data bank for metering and imbalance settlement data, so it is natural for all up-to-date and corrected metering data and the results calculated from them to be available in Datahub.
Official imbalance settlement always closes when the balance window closes, after which data calculated in official imbalance settlement and reported to eSett can no longer be changed. Changes in metering data outside the balance window are mainly taken into account in balance deviation calculation. Balance deviations are, however, registered neither to exchange points nor production units, nor to those accounting points at which a metering error arises more than six weeks after the period of a terminated sales agreement. The updating of the results of imbalance settlement calculations in connection with balance deviation calculation is therefore not possible. This concerns not only metering grid area losses but also other imbalance settlement aggregations.
Calculation results corresponding to the official imbalance settlement are calculated for the period outside the balance window for all metering grid areas over the past three years upon request. These results are retrievable using DH-520 data request events. In the request event, the party must state whether it is searching for official data locked in the imbalance settlement or for the results of the correction calculations described above. Correction calculations can also be performed separately for a freely specified period upon request.