Section S - Supplier Volume Allocation Simple Guide

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Section S – Supplier Volume Allocation

Simple Guide


Section S and its associated Annexes set out the rules by which Primary Supplier BM Unit Metered Volumes are determined from a combination of Half Hourly (HH) and Non Half Hourly (NHH) Metering Systems. It describes the obligations on Suppliers to provide data and to ensure that Supplier Agents (i.e. certain Party Agents - principally Meter Operator Agents (MOAs), Half Hourly Data Collectors (HHDCs), Half Hourly Data Aggregators (HHDAs), Non Half Hourly Data Collectors (NHHDCs) and Non Half Hourly Data Aggregators (NHHDAs)) undertake the requirements defined for them.

Section S also sets out the rules and provisions by which Suppliers, Virtual Lead Parties (VLPs) and Asset Metering Virtual Lead Parties (AMVLP), shall notify to the Supplier Volume Allocation Agent (SVAA) which Metering Systems should be treated as belonging to a Secondary BM Unit, with regards to VLPs and AMVLP’s, or a Primary Additional BM Unit, with regards to Suppliers, for the purposes of providing TERRE or BM Balancing Services.

Section S: Annex S-2 defines the detailed Supplier Volume Allocation (SVA) Rules for determining Primary Supplier BM Unit Metered Volumes, and Section S: Annex 1 defines Performance Levels with which Suppliers and their Supplier Agents must comply, together with a Menu of Supplier Charges (also known as Liquidated Damages within the Code Subsidiary Documents) in the event that they do not.

Supplier ID

A Supplier ID is a reference by which a Supplier is uniquely identified, for SVA purposes, in the Central Switching Service (CSS) under the Retail Energy Code (REC) and the relevant Supplier Meter Registration Service (SMRS) under the BSC1. A Supplier may hold no more than three Supplier IDs unless the additional Supplier IDs are held pursuant to a transfer or a request for additional Supplier IDs is granted by the Panel. The responsibilities of Suppliers and Supplier Agents, Primary Supplier BM Units, Supplier Volume Allocation rules apply separately to each Supplier ID.

Supplier IDs can be transferred between Suppliers. The Supplier transferring the Supplier Id must give notice in writing to Elexon. The notification includes information concerning the transfer and must be signed by both Suppliers. Requests received before 12:00 can take effect (at the earliest) from the following day (effective at midnight, start of day), whilst requests received after 12:00 can take effect (at the earliest) from the day after the following day. Elexon sends a copy of this notice to the Authority, each Party and the Central Registration Agent (CRA).

From the time and date the ID transfer is to take place the ID Transferee becomes responsible (and the ID Transferor ceases to be responsible) for all Imports and Exports for the relevant Primary BM Units, the registration of all relevant Metering Systems, Plant and Apparatus, the associated Supplier Agent appointments and the Trading Charges and BSCCo Charges. The ID Transfer’s obligations and liabilities in respect of dates before the transfer date (e.g. from Reconciliation Runs) remain unchanged. The ID transferral shall not affect Energy Contract Volume Notifications (ECVNs), Metered Volume Reallocation Notifications (MVRNs) or the contractual arrangements between the Transferor/Transferee and their Party Agents.

Following the transfer of Supplier ID, the CRA shall establish a Transferee Primary BM Unit for each Relevant Primary BM Unit with the same attributes (e.g. Demand Capacity/Generation Capacity and Production/Consumption Status). This will be as if it was registered by the ID Transferee on the ID Transfer Date and the corresponding Primary BM Unit cancelled by the ID Transferor on that date. The Primary BM Unit Metered Volumes shall be transferred between the Primary BM Units as long as they were submitted before the ID Transfer Date. Data and rights relating to the Relevant Primary BM Units automatically are reassigned from the ID Transfer Date provided this is legally possible.

The ID Transferee shall have a right to access records, information and data as required and the ID Transferor shall take all reasonable steps to cooperate. With regards to transfer of Plant or Apparatus, which are subject to Shared SVA Meter Arrangement, the ID Transferee shall be bound by the Allocation Schedule and status prior to the transfer.

Responsibilities of Suppliers and Supplier Agents

The Supplier must appoint Supplier Agents in accordance with Section J and, for SVA MOAs, the REC. The Supplier will be responsible for all actions taken or not taken by the Supplier Agents it appoints, in relation to Metering Systems for which that agent is appointed. Each Supplier must record the Supplier Agents appointed to each SVA Metering System in the relevant SMRS.

For NHH Systems that are compliant with the Smart Metering Equipment Technical Specifications (SMETS), the Supplier shall establish and maintain and provide Meter Technical Details (MTDs) to enable the NHHDC to process data in accordance with SVA Rules. On registering a Smart compliant meter, the Supplier shall provide the meter configuration details to the MOA, who will then provide additional asset specific details and forward the full MTDs to the NHHDC.

HHDCs are responsible principally for collecting and validating Metered Data and providing SVA Metering System data to the relevant Data Aggregators. NHHDCs are additionally responsible for calculating and providing Annualised Advance (AA) and Estimated Annual Consumption (EAC) data using Daily Profile Coefficients provided by the SVAA. When a Supplier appoints a Data Collector for a Metering System for which it is responsible, it must send the Data Collector information concerning the Metering System, which is registered in the relevant SMRS. The Supplier should also send any Customer-own reads to the Data Collector, except where the Supplier has good reason to believe that it is invalid.

HHDAs are responsible for calculating and providing to the SVAA SVA Metering System data, for each Supplier that appointed it, aggregated by GSP Group and Consumption Component Class2, and also any Additional BM Unit data and for receiving Line Loss Factors from the BSC Website and applying them. Where applicable, HHDAs must provide metered data to an EMR Settlement Services Provider.

NHHDAs are responsible for providing to the SVAA, for each Supplier that appointed it, AA and EAC data aggregated by GSP Group, Profile Class3, Standard Settlement Configuration4 and Line Loss Factor Class. For all Metering System for which they are responsible, Suppliers must send the relevant Data Aggregator information held in the relevant SMRS concerning the Metering System. HHDAs and NHHDAs are also responsible for maintaining standing data.

NHHDAs may be required to provide the relevant Licensed Distribution System Operator (LDSO) with EAC data and Metering System details in accordance with Section S: Annex S-2.

Meter Administrators, also appointed by Suppliers, are responsible for calculating deemed metered volumes for HH Unmetered Supplies and providing that data to the relevant HHDC.

Supplier Obligations

When a Supplier registers a new Metering System in CSS it must allocate the Metering System to a Profile Class and Standard Settlement Configuration in SMRS, in accordance with BSCP501. For existing Metering Systems it must ensure that the Metering System continues to be allocated to the correct Profile Class. Suppliers are required to co-operate with the Profile Administrator in the provision of customers to contribute to the load research sample.

With respect to SVA and SMETS compliant NHH Metering Systems, Suppliers are obliged to hold the MTDs and, in the case of NHH Metering Systems, the valid Metered Data obtained during the preceding 40 months for each relevant Settlement Register. In addition, the Supplier shall hold the latest values of the EAC and the AA.

Long Term Vacant Sites

A Supplier who treats a NHH Metering System as Long Term Vacant must keep auditable records of its compliance and provide the Metering System details to the LDSO as requested.

Provision of Data to a CM Settlement Services Provider

Suppliers shall ensure that, if requested to do so by a Customer or generator with Capacity Market (CM) assets subject to Capacity Agreement, its HHDA provides metered data relating to that SVA Metering System to the CM Settlement Services Provider.


The performance of Suppliers and Supplier Agents in respect of the requirements of Section S affects the allocation of volumes for all Suppliers. Accordingly Suppliers are obliged to ensure that they and their Supplier Agents meet certain Performance Levels. The Supplier is required to provide information to the Performance Assurance Board (PAB) to demonstrate that it and each of its Supplier Agents are discharging their responsibilities to the Performance Levels, as defined in Section S: Annex S-1.

In the event of any failure to comply with the Performance Levels, Section S: Annex S-1 also sets out a Menu of Supplier Charges for which the Supplier is liable. A number of events of Supplier Force Majeure are defined, which exempt the Supplier from the liability to pay charges.

Functions of BSC Agents in relation to Supplier Volume Allocation

The SVAA must (in accordance with the relevant provisions of the BSC and Code Subsidiary Documents (including BSCP508)) provide a supplier volume allocation service in accordance with the SVA Rules contained in Section S: Annex S-2, provide a daily profile production service and provide a Market Domain Data (MDD) service to the electricity market. MDD comprises information required by Suppliers and Supplier Agents, and includes information necessary for the SVA Rules, such as details of GSP Groups, Profile Classes, Standard Settlement Class Configurations and Time Pattern Regimes.

The SVAA should provide data to the NETSO and Distribution System Operators for the purposes of calculating transmission and distribution use of system charges respectively, and to the SAA for the provision of Relevant EMR Settlement Data to an EMR Settlement Services Provider. Additionally the SVAA must perform related services if requested by the Panel, including the provision of a contingency plan and disaster recovery service, and the provision of a helpdesk service.

The Profile Administrator creates and maintains a load research sample, provides Regression Coefficients and Group Average Annual Consumptions for a number of Profile Classes to Parties, the SVAA, Supplier Agents and to Elexon. In the event that Elexon provides the Profile Administration Services usually provided by the Profile Administrator, as provided for in Section C of the Code, references to the Profile Administrator should be construed as references to Elexon.

The Teleswitch Agent monitors radio messages sent to teleswitched SVA Metering Systems and provides data on switching times to the SVAA. The Teleswitch Agent must also report to the SVAA any known or suspected failures in the monitoring and provision of messages.

Functions of Other Agents in relation to Supplier Volume Allocation

Each LDSO, in its capacity as a Supplier Meter Registration Agent (SMRA), is responsible for establishing, operating and maintaining (either directly or by procuring) a Supplier Meter Registration Service (SMRS) for SVA Metering Systems and associated data, in accordance with the REC, Section K, (including Annex K-1) the Supplier Volume Allocation Rules and BSCP501.

Each SMRA shall ensure that the data it is responsible for is accurate and complete, and that its SMRS enables only one Supplier to be registered as responsible for Imports at a Metering System for a particular Settlement Day.

Primary Supplier BM Units

HHDAs must be Qualified, as covered in Section J. HHDAs may be Qualified to aggregate data from Metering Systems provided by HHDCs to provide metered consumption values (known as BM Unit's Metered Consumption) for one or more Primary Supplier BM Units (i.e. a Primary Base BM Unit and Primary Additional BM Units) in each GSP Group. However, HHDAs can be Qualified to provide only metered consumption values (known as Supplier's Metered Consumption) for only one Primary Supplier BM Unit totalled for the Supplier (i.e. a Primary Base BM Unit only) in each GSP Group.

This provides compatibility for systems of HHDAs that complied with the Pooling & Settlement Agreement but which do not have the functionality to allocate consumption into Primary Additional BM Units as well as Primary Base BM Units.

Where a Supplier registers a Primary Additional BM Unit (in accordance with Section K), the Primary Additional BM Unit may comprise one or more HH Metering Systems and/or one or more sets of NHH Metering Systems in the same GSP Group, each set comprising all the NHH Metering Systems registered to that Supplier having the same Profile Class and Standard Settlement Configuration. The Supplier must inform the relevant HHDAs and NHHDAs accordingly.

Supplier Volume Allocation Rules

All clauses in Section S: Annex S-2 are treated as being part of Section S and have effect, even if not specifically referenced by Section S or any other section of the BSC. Suppliers and Supplier Agents are required to provide data to the SVAA in accordance with the SVA Rules and BSCP508. The SVA Rules set out in Section S: Annex S-2 provide for:

(a) the provision of SVA Metering System information from the relevant SMRS to Suppliers and Supplier Agents;

(b) provision of standing data to the SVAA by Suppliers, Supplier Agents, LDSOs and others;

(c) provision of periodic data to the SVAA by Data Aggregators, the Temperature Provider and the Teleswitch Agent;

(d) the calculations performed by Data Collectors and Data Aggregators on behalf of Suppliers;

(e) the principal functions of the SVAA, including deriving profile data, distributing Daily Profile Coefficients to NHHDCs; determining uncorrected import and export volumes; applying GSP Group Correction Factors; and determining the half hourly energy volumes for each Supplier BM Unit and providing these to the Settlement Administration Agent (SAA).

SVA Metering System Balancing Services Register

Where a Supplier, VLP or AMVLP has registered one or more BM Units (in accordance with Section K) and intends to offer Balancing Services, the Lead Party of that BM Unit is obligated to notify the SVAA of the Metering Systems they intend to use in their BM Unit(s) via MSID Pair allocations.

An ‘MSID Pair’ means one Import Metering System and, where applicable, one Export Metering System situated at a single Boundary Point for the purposes of the providing Replacement Reserve (RR) or Balancing Mechanism (BM) services. To clarify a MSID Pair must contain a HH Import Metering System but does not always have to have to contain a HH Export Metering System.

Similarly an AMVLP will register it’s “behind the boundary point” metering asset(s) with the SVAA, which will in turn generate “AMSID Pairs” for valid assets. These AMSID Pairs can then be registered against Secondary BM Unit(s) for either Asset Metering or Asset Differencing. Note that a second AMVLP may allocate the same AMSID Pair to a Secondary BM Unit.

For the avoidance of doubt a HH Metering System within a MSID Pair may not be allocated to more than one MSID Pair and a MSID Pair may not be allocated to more than one BM Unit that offers Balancing Services for any given time.

To permit more accurate Settlement of Bid Offer Acceptances, particularly where a BM Unit contains MSID Pairs (or AMSID Pairs) for which it is difficult for the Lead Party to forecast the baseline metered volume accurately, Lead Parties can register a BM Unit as a Baselined BM Unit and classify MSID/AMSID Pairs as Baselined, along with the Baselining Methodology that applies.

Once MSID Pair Allocation is received, the SVAA shall validate and notify the Lead Party whether the allocation was successful or not. Where it confirms the relevant allocation (in accordance with Section S), the SVAA shall record the relevant data in the SVA Metering System Balancing Services Register. If the HH Metering System is already allocated to another BM Unit that offers Balancing Services, the SVAA will confirm the most recent allocation and notify the previous SVA Metering System Balancing Service Register registrant of the loss of MSID Pair Allocation.

In respect of a Primary BM Unit, upon being informed that a HH Metering System will no longer be allocated to that Primary BM Unit for the purposes of providing Balancing Services in Settlement, it is the responsibility of the Supplier of that Primary BM Unit to ensure that such HH Metering System is not subsequently used for any inappropriate Balancing Services activity.

Where the SVAA confirms a VLP MSID Pair or a AMVLP Pair, allocation for a Secondary BM Unit it shall:

(a) procure MSID Standing Data in accordance with Annex S-2; and

(b) store MSID Standing Data in the SVA Metering System Balancing Services Register.

MSID Standing Data means in relation to each Metering System:

(a) the GSP Group in which the Metering System is located;

(b) the Supplier ID of the Supplier that has registered the Metering System in CSS (in accordance with Section K); and

(c) the HHDA appointed in relation to that Metering System.

Baselined BM Units and Submitted Expected Volumes

Where a Lead Party has registered a BM Unit as a Baselined BM Unit (pursuant to Section K), the Lead Party shall provide the Submitted Expected Volume to the SVAA in accordance with BSCP602 and ensure the accuracy of this value is in line with Good Industry Practice. The SVAA will validate and notify the Lead Party of received Submitted Expected Volumes, and the confirmation or rejection of these.

Where a Baselined BM Unit contains no Baselined MSID Pairs or Baselined AMSID Pairs, the Submitted Expected Volume sent to the SVAA by a Party must be the same as the Final Physical Notification.

The Baselining Methodology Document outlines the methodologies the SVAA will use to calculate MSID Baseline Values and AMSID Baseline Values, for all Baselined MSID Pairs and Baselined AMSID Pairs, based on historical volume data.

The Lead Party can inform the SVAA of Event Days (in accordance with BSCP602) where consumption on an Event Day shall not be included in calculating MSID Baseline Values or AMSID Baseline Values (save as provided in the Baselining Methodology Document).

SVAA will aggregate the Submitted Expected Volume and all of the MSID Baseline Values to derive a Settlement Expected Volume (SEVij) (for each Baselined BM Unit and Settlement Period). SVAA will send the Settlement Expected Volume to SAA, who will use it (in place of the Final Physical Notification) to verify that the BM Unit has delivered the Bid Offer Acceptance instructed by the NETSO.

Unmetered Supplies

Each LDSO must be Qualified, as covered in Section J. Each LDSO must determine whether any supply of electricity connected to its Distribution System(s) or its Associated Distribution System(s) that does not have a SVA Metering System is to be treated as an Unmetered Supply. It will not determine that a supply could be treated as unmetered unless installing metering is either infeasible or would cost an amount disproportionate to the supply.

If the LDSO decides that a supply should be unmetered, it decides whether that supply should be either:

(a) Profiled Unmetered, in which case the supply is assigned an EAC which, in combination with the appropriate profile, is used to determine the estimated consumption of that supply; or

(b) use Equivalent Metering, where half-hourly consumption values are calculated by using a technique that complies with BSCP520 that governs such calculations.

If a supply is to be treated as unmetered, the LDSO will issue the customer with an Unmetered Supply Certificate which will state whether the Unmetered Supply to which it relates is an Equivalent Unmetered Supply or a Profiled Unmetered Supply.

An LDSO when carrying out the above functions relating to Unmetered Supply may be referred to as an Unmetered Supplies Operator (UMSO).

Demand Disconnection Events

Duties of the LDSO

The Host LDSO is required to inform any embedded LDSO when it becomes aware of a Demand Disconnection Event that affects the Embedded Distribution System.

Following the cessation of a Demand Disconnection event the impacted DSOs have to identify the affected SVA Metering Systems that were energised and registered but were not subject to a voluntary reduction in consumption as a result of the event.

The DSO then informs the appropriate Data Collectors and Data Aggregators of the identified MSIDs and the start and end times (in Co-Ordinated Universal Time (UTC)) of the disconnection event within 5 Business Days, updating this information where necessary.

Duties of the NETSO

Within 25 Business Days of the Demand Disconnection Event the NETSO has to inform the SVAA of the MSID and the estimated volume of Non-BM STOR Metering systems that were subject to an instruction. The providers of Non-BM STOR have to co-operate with the NETSO in providing this data.

Duties of the SVAA

Within one Business Day the SVAA takes the data from the NETSO (above) and provides it to the appropriate Data Collectors and Data Aggregators and provides amendments as necessary.

Need more information?

For more information, please contact the BSC Service Desk at or call 0370 010 6950.

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1 There is one SMRS per Licensed Distribution System Operator (LDSO).

2 All consumption is allocated to a Consumption Component Class. Different Consumption Component Classes may then be accorded different treatment in GSP Group Correction. The classification is defined in Section X of the BSC and uses a number of bases such as whether the quantity is import or export, measured or estimated and whether the premises are above or below 100kW. Also Consumption Component Classes are defined for the line losses associated with consumption that are separate from the Consumption Component Classes to which the basic consumption is allocated.

3 For NHH Metering Systems, the Profile Class determines which set of the coefficients provided by the Profile Administrator is used in profiling meter advance data into half hourly consumptions (based, for example, on whether the Metering System is at domestic or non-domestic premises).

4 In general, a Metering System that has a radio teleswitch or timeswitch will have more than one register for which a reading should be taken. The Standard Settlement Configuration defines which Time Pattern Regime is associated with each of the registers for all Metering Systems allocated to that Standard Settlement Configuration. The Time Pattern Regime defines the times at which a register with which it is associated will either start or stop recording consumption, or that the register is teleswitched.