Shared Supplier Volume Allocation (SVA) Metering System obligations

The Trading Disputes Committee (TDC) has recently encountered a number of Trading Disputes where the root cause was determined to be issues with implementing or maintaining a Shared Supplier Volume Allocation (SVA) Metering System. We want to ensure that Parties understand their obligations and the processes they must follow to prevent future impacts to Settlement.

To help BSC Parties to understand their obligations, we have collated some key points within the process that BSC Parties and Party Agents should consider when implementing and maintaining a Shared SVA Metering System. It is not an exhaustive list and Parties responsible for Shared SVA Metering Systems should ensure they have read and understood BSCP550 in its entirety.

What is a Shared SVA Metering System?

A Shared SVA Metering System is single SVA Metering System comprising of Half Hourly Metering Equipment for Exports or Imports, which two or more Suppliers are responsible. This is facilitated by the creation of multiple Metering System Identifiers (MSIDs). This consists of a Primary MSID and one or more pseudo Secondary MSIDs. A pseudo Secondary MSID is an extra Metering System Identifier, created to split the metered volumes from an Metering System for Settlement purposes. Energy is split between the various MSIDs through a specific splitting method.

In the Shared SVA Metering System, the Primary Supplier is responsible for the Primary MSID, and one or more Secondary Suppliers are responsible for the relevant pseudo Secondary MSIDs.

What obligations do I have?

In order to avoid future Trading Disputes and ensure the smooth running of Shared SVA Metering Systems, there are actions that Parties must take.

These obligations include the following:

Suppliers associated with a Shared SVA Metering System must have an agreement between themselves that allows fast and co-operative communication. The Suppliers must agree between themselves who will act as the Primary Supplier and the pseudo Secondary Supplier. In addition to this, if the splitting method used is a Fixed Block or a Multiple Fixed Block then the associated Suppliers should determine who is the Fixed Supplier and who the Variable Supplier.

The Primary Supplier is responsible for the Primary MSID and for the associated new pseudo Secondary MSID(s) until the change of Supplier process is completed. Each Secondary Supplier will take subsequent responsibility for a pseudo Secondary MSID.

Each Supplier is responsible for appointing a SVA Meter Operator Agent (MOA), Half Hourly Data Collectors (HHDC) and Half Hourly Data Aggregator (HHDA) for their respective Shared SVA MSID and for maintaining its own registration details in Supplier Meter Registration Service (SMRS). In respect of the SVA MOA and HHDC appointments, all Suppliers shall appoint the same Party Agents.

The Licensed Distribution System Operator (LDSO) is responsible for maintaining a record of the Primary and pseudo Secondary MSIDs it has issued, together with the association between them . For example, that there is only one physical Metering System (MS), and ensuring no duplicates are created. For this reason it is important that the Primary Supplier communicates with the LDSO at the registration stage to ensure that pseudo Secondary MSIDs are identified when registered.

The determination of Measurement Class for the Import Site requires special processing by Suppliers. Suppliers therefore have a choice of:

  • Calculating the Measurement Class based on the total consumption at the Site
  • Registering the Site as Measurement Class ‘C’, and thereby treating it as above 100kW for performance assurance purposes

When the Primary Supplier completes the registration of the pseudo Secondary MSID(s) for a new connection (3.1) or change of Supplier (3.2), the Supply Start Date (SSD) specified shall be sufficiently in advance of the required contract SSD. This is to enable the Secondary Supplier(s) to undertake the change of Supplier process by the contracted SSD, taking into account the 10-day lockout period. The pseudo Secondary MSID(s) shall be registered as de-energised during this interim period to avoid erroneous metering data being passed into Settlement.

The Primary MSID is the enduring MSID for any changes between single and Shared SVA Meter Arrangements and shall have the Meter Technical Details (MTD) for the physical MS assigned to it. The pseudo Secondary MSID(s) shall only exist whilst there is Shared SVA Meter Arrangement. The MTD for pseudo Secondary MSID(s) shall be amended so that the Meter Multiplier and Pulse Multiplier are set to zero to minimise the risk of duplicate metering data entering the Settlement process. It is crucial that the MTDs associated with the pseudo Secondary MSIDs have the Meter Multiplier and Pulse Multiplier set to zero as this is the main mitigation against double counting in Settlement. The HHDC should validate pseudo Secondary MSIDs to highlight where a Shared SVA Metering System has MTDs related to pseudo Secondary MSIDs where the multipliers are not set to zero.

The method and proportion of the split for a Shared SVA Metering System is communicated to the HHDC via an Allocation Schedule (sent via the Primary Supplier). For full rules on Allocation Schedules see Section 4.3.1 (Allocation Schedules related to full Settlement Days) or Section 4.3.2 (Allocation Schedules for part Settlement Days) of BSCP550.

Suppliers will ensure the Allocation Schedule for splitting the Half Hourly Active Energy data between them complies with the requirements set out in the relevant Appendices and is provided to the HHDC by Gate Closure. If the Allocation Schedule is received after Gate Closure for the start of the Settlement Day to which it is related, then that Allocation Schedule will not be used by the HHDC, and the existing one will be used instead.

Where the splitting is achieved via the Non Settlement Meter method, the Suppliers must agree (in advance of Gate Closure, and as part of the Allocation Schedule if appropriate) how Active Energy should be apportioned in the event that Meter readings from one or more of the non-Settlement Meters are unavailable. For example, the Allocation Schedule could include a default allocation to be used in the event of non-Settlement metering faults.

It is possible for a Shared SVA Metering System to also be subject to a Complex Site agreement. The SVA MOA should refer the Retail Energy Code (REC) for details regarding the D0268 `Half Hourly Meter Technical Details’ dataflow and the `Complex Site Supplementary Information Form’.


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