Primary BM Units are the units used under the Balancing and Settlement Code (BSC) to account for all energy that flows on or off the Total System (the Transmission System and each Distribution System combined). A Primary BM Unit is the smallest grouping of generation and / or demand equipment that can be independently metered for Settlement and all generation and demand equipment must be captured in a Primary BM Unit.

Secondary BM Units can be registered by Virtual Lead Parties (VLPs). Supplier Volume Allocation (SVA) Half Hourly (HH) metered generation and / or demand equipment within a single Grid Supply Point (GSP) Group can be allocated to a Secondary BM Unit for the purpose of providing Trans-European Replacement Reserves Exchange (TERRE) Balancing Services to the National Electricity Transmission System Operator (NETSO). This equipment will also be registered in a Primary BM Unit.

Where equipment is in both a Primary and Secondary BM Unit, the Supplier is responsible for balancing the Primary BM Unit and should contract for all the energy required to balance that BM Unit. If the equipment is also in a Secondary BM Unit and is called upon by the NETSO for Balancing Services, Settlements will adjust the Primary BM Unit so that the Supplier is not affected.

Note that an SVA Metering System must only be providing Balancing Services through one BM Unit (Primary or Secondary) at any particular time to prevent double counting in Settlement.

BSCP15: BM Unit Registration tells you how to register Primary and Secondary BM Units. BM Units can also be registered on the Self-Service Gateway (Elexon Kinnect Customer Solution).

Types of BM Units

There are several types of BM Unit, each representing different aspects of the system. Each type is marked with prefixes in their IDs, as given below. Each type is described separately in the following sections, along with an overview of the registration process and what you need to do.

If you are only interested in a particular type of BM Unit, refer to the relevant section. The list below describes each type:

BM Unit Type	Prefix	Overview
Directly Connected	T_	Primary BM Units directly connected to the Transmission System.
Embedded	E_	Primary BM Units embedded within a Distribution System.
Interconnector	I_	Primary BM Units related to an Interconnector.
Supplier	2_	Primary BM Units covering Supply. These contain all of a particular Supplier’s Meters for a given Grid Supply Point (GSP) Group in either a Base or Additional Supplier Primary BM Unit.
Supplier	C_	These Additional Supplier Primary BM Units are registered solely for the purpose of allocating Contracts for Difference (CfD) Assets.
Secondary	V_	Secondary BM Units may be registered by a Virtual Lead Party to provide TERRE Balancing Services to the NETSO.
Miscellaneous	M_	Other types of Primary BM Units that don’t fit the above categories. This prefix does not apply to newly registered Primary BM Units.

Primary BM Units submit Physical Notifications (PNs) to the NETSO if their Generation or Demand Capacity is at or above 50MW in England and Wales, 30MW in South Scotland or 10MW in North Scotland. It is optional below these limits. Interconnector Primary BM Units always submit PNs.

Directly Connected Primary BM Units

What is a Directly Connected Primary BM Unit?	Directly Connected Primary BM Units comprise of equipment directly connected to the Transmission System. They are usually Generation Units, relating to Power Stations or other Generating sites (e.g. wind farms) but can also be large demand sites. The equipment within each Primary BM Unit is independently controlled, and is metered separately.
Do I need to do anything before registering one?	You normally need to Qualify as a Generator to register Generation Directly Connected Primary BM Units or as a Supplier to register Demand Primary BM Units. If the Primary BM Unit will be Exempt Export (see below for more details), you may also register the Primary BM Unit if you are a Qualified Supplier. Visit the Market Entry page or BSCP65: Registration of Parties and Exit Procedures for more details. Before you submit the Primary BM Unit registration form you must contact the NETSO , to discuss any obligations and sign the necessary contractual agreements. The NETSO¹ will give you a NGC BM Unit Id.
What forms do I need to fill in?	BSCP15/4.1 gives general details of the Primary BM Unit(s) you’re registering. You must send the BSCP15/4.1 form to the Central Registration Agent² (CRA) at least 30 Working Days (standard Primary BM Unit) or at least 60 Working Days (non-standard Primary BM Unit) before the Effective From Date (EFD). A BM Unit can also be registered on the Self-Service Gateway (Elexon Kinnect Customer Solution). BSCP15/4.13 requests a non-standard Primary BM Unit configuration. If your Primary BM Unit is non-standard, this must be submitted in addition to the BSCP15/4.1 form or the BM Unit can also be registered on the Self Service Gateway (Elexon Kinnect Customer Solution). BSCP20/4.1 ³ registers the Metering Systems related to your Primary BM Unit(s) and must be sent to the CRA2 at least 20 Working Days before the EFD. BSCP20/4.3 registers the Meter Technical Details (MTDs) related to the Metering Systems of your Primary BM Unit(s), and is usually submitted by the Meter Operator Agent (MOA) to the CDCA2 at least 16 Working Days before the EFD. It can also be submitted by the Registrant of the Metering System. BSCP75/4.2 details the Aggregation Rules for the Primary BM Unit(s) and must be sent to the CDCA at least 20 Working Days before the EFD⁴ . BSCP02 details the Proving Test that your MOA must carry out on the Metering System. This must be completed at least 8 Working Days before the EFD. You must provide an electrical single line diagram of the site showing: the location of the Metering Equipment, in particular the Settlement current and voltage transformers (CTs/VTs) and CT/VT ratios; any existing Boundary Points and/ or any System Connection Points at or near the proposed Boundary Point(s); and any back up SVA connection and interlocking arrangements.
What information do I provide on the BSCP15/4.1 form?	The NGC BM Unit ID is the ID provided by the NETSO (where the Final Physical Notification (FPN) flag is Y). The Primary BM Unit ID has a prefix of ‘T_’ followed by the NGC BM Unit ID. The Primary BM Unit Type is ‘T’ for Directly Connected and the Primary BM Unit Configuration depends on what type of Unit it is – please check the list at the bottom of the form. You need to enter the Generation Capacity (GC) and Demand Capacity (DC) of each Primary BM Unit, as well as the Final Physical Notification (FPN) Flag. If you are using the Self-Service Gateway (Elexon Kinnect Customer Solution) you will need to enter the Maximum +ve QMij, and Maximum Negative QMij which will be doubled in the system to give the GC and the DC. If the Primary BM Unit will be Exempt Export (see below for more details), you must put ‘Y’ in the relevant column, and complete a BSCP15/4.5 form. The Exempt Export information can also be registered on the Self-Service Gateway (Elexon Kinnect Customer Solution). Finally, you need to state the proposed date on which the Primary BM Unit will become effective. Further guidance on completing this form is given in the ‘completing the BSCP15/4.1’ section below.
What other information is needed?	If you register the Primary BM Unit(s) as Exempt Export, refer to the Exempt Export section which covers additional processes that you need to follow.
When do I need to submit these forms by?	You need to start the process at least 30 Working Days before your proposed Effective From Date if your Primary BM Unit is standard or at least 60 Working Days before your Effective From Date if your Primary BM Unit is non-standard. Forms can be submitted in any order, providing you meet the timescales above. Alternatively, this information (apart from the BSCP15/4.13 form) can be completed via the Self-Service Gateway (Elexon Kinnect Customer Solution).

For Generation Primary BM Units, more detail on registration and guidance on the market entry process can be found in the guidance BM Units – How to register Primary BM Units relating to Generating Plant in the Central Volume Allocation Market.

Embedded Primary BM Units

What is an Embedded Primary BM Unit?	Embedded Primary BM Units comprise of equipment that is connected to a Distribution Network. They are Generation Units relating to Power Stations or other generating sites (e.g. wind farms). They can include the imports relating to these sites, but large embedded demand sites without any generation cannot be registered as a Central Volume Allocation (CVA) Primary BM Unit. The equipment within each Primary BM Unit is independent of other Units, and is metered separately.
Do I need to do anything before registering one?	You need to Qualify as a Generator to register Embedded Primary BM Units. If the Primary BM Unit will be Exempt Export (see below for more details), you may also Qualify as a Supplier to register the Primary BM Unit or elect another Generator or Supplier Party to register the Primary BM Units. Visit the Market Entry page or BSCP65: Registration of Parties and Exit Procedures for more details. Before you submit the Primary BM Unit registration form, and if you wish to participate in the Balancing Mechanism (i.e. (FPN) Flag is set to Yes) you must contact the NETSO⁵ , to discuss any obligations and sign the necessary contractual agreements. The NETSO will give you NGC BM Unit Id(s).
What forms do I need to fill in?	BSCP15/4.1 gives general details of the Primary BM Unit(s) you’re registering. You must send the BSCP15/4.1 form to the Central Registration Agent⁶ (CRA) at least 30 Working Days (standard Primary BM Unit) or at least 60 Working Days (non-standard Primary BM Unit) before the Effective From Date (EFD). BM Units can also be registered on the Self-Service Gateway (Elexon Kinnect Customer Solution). BSCP15/4.13 requests a non-standard Primary BM Unit configuration. BM Units can also be registered on the Self-Service Gateway (Elexon Kinnect Customer Solution). BSCP20/4.1 ⁷ registers the Metering Systems related to your Primary BM Unit(s) and must be sent to the CRA²at least 20 Working Days before the EFD. BSCP20/4.3 registers the Meter Technical Details (MTDs) related to the Metering Systems of your Primary BM Unit(s), and is usually submitted by the Meter Operator Agent (MOA) to the CDCA² at least 16 Working Days before the EFD. It can also be submitted by the Registrant of the Metering System. BSCP75/4.2 details the Aggregation Rules for the Primary BM Unit(s) which must include reference to CVA Line Loss Factors and must be sent to the CDCA at least 20 Working Days before the EFD⁸ . BSCP02 details the Proving Test that your MOA must carry out on the Metering System. This must be completed at least 8 Working Days before the EFD. You must provide an electrical single line diagram of the site showing: the location of the Metering Equipment, in particular the Settlement current and voltage transformers (CTs/VTs) and CT/VT ratios; any existing Boundary Points and/ or any System Connection Points at or near the proposed Boundary Point(s); and any back up SVA connection and interlocking arrangements.
What information do I provide on the BSCP15/4.1 form?	The NGC BM Unit ID is provided by the NETSO (where FPN flag is Y). The Primary BM Unit ID has a prefix of ‘E_’ followed by the NGC BM Unit ID. The Primary BM Unit Type is ‘E’ for Embedded. The Primary BM Unit Configuration depends on what type of Unit it is - please check the list at the bottom of the form. You need to enter the GC and DC of each Primary BM Unit, as well as the FPN Flag, and the GSP Group ID in which the Primary BM Unit is located. If you are using the Self-Service Gateway (Elexon Kinnect Customer Solution) you will need to enter the Maximum +ve QMij, and Maximum Negative QMij which will be doubled in the system to give the GC and the DC. If the Primary BM Unit will be Exempt Export (see below for more details), you must put ‘Y’ in the relevant column, and complete a BSCP15/4.5 form. Finally, you need to state the proposed date on which the Primary BM Unit will become effective. Further guidance on completing this form is given in the ‘completing the BSCP15/4.1’ section below.
What other information is needed?	Embedded Primary BM Units need CVA Line Loss Factors (LLFs) for use in their Aggregation Rules. The relevant Licensed Distribution System Operator (LDSO) is responsible for submitting them within the LLF timescales in BSCP128: Production, Submission, Audit and Approval of Line Loss Factors. Please ask the LDSO to submit CVA LLFs (as opposed to SVA LLFs) for the site and to cancel any SVA MPANs that they may have created for the site. If you register the Primary BM Unit(s) as Exempt Export, refer to the Exempt Export section, which covers additional processes that you need to follow.
When do I need to submit these forms by?	You need to start the process at least 30 Working Days before your proposed Effective From Date if your Primary BM Unit is standard or at least 60 Working Days before your Effective From Date if your Primary BM Unit is non-standard. Forms can be submitted in any order, providing you meet the timescales above. Alternatively, this information (apart from the BSCP15/4.13 form) can be completed via the Self-Service Gateway (Elexon Kinnect Customer Solution).

Standard and Non-Standard Primary BM Unit Configuration

The BSC requires that a Primary BM Unit must satisfy the following criteria (Section K3.1.2);

only one Party is responsible for the Exports and/or Imports from or to the Plant and/or Apparatus registered in Central Meter Registration Service (CMRS) (another Party may be responsible for an Supplier Meter Registration Service (SMRS) registered connection as in point (d));
the Exports and/or Imports relating to the Primary BM Unit are capable of being controlled independently of any other Exports and/or Imports which do not relate to the Primary BM Unit;
the Metered Volumes from the Primary BM Units Plant and Apparatus are submitted separately from any Plant and Apparatus not part of the Primary BM Unit
the Primary BM Unit does not contain Plant and/or Apparatus whose Imports and Exports are measured by both CVA and SVA Metering Systems except where:

0.0.1 the Registered Capacity of the Boundary Point measured by the Metering System(s) registered in SMRS is equal to or less than the limit determined by the Panel, currently 415V;

0.0.2 the Plant and Apparatus cannot Export through the Metering System registered in SMRS; and

0.0.3 there are measures in place to prevent instantaneous flow through of electricity:

i.e. a backup connection to the Distribution System with registered capacity of less than 415V and with Metering systems registered in SMRS is allowed; and

Plant and Apparatus with a Registered Capacity of less than or equal to the size of a Small Power Station may be aggregated up to the size of a Small Power Station⁹ (size applicable to both Imports and Exports) within a single Primary BM Unit. A Primary BM Unit comprised of Plant and Apparatus with a Registered Capacity of greater than the size of a Small Power station must be the smallest aggregation of the Plant and Apparatus for which the requirements mentioned in (a) to (c) would be met.

In addition to Primary BM Units meeting the criteria above, the BSC states a number of exceptions that are also considered to be a single Primary BM Unit (Section K3.1.4). These are included in the list Permissible Configurations of Plant and Apparatus on page on page 9 below;

Any configuration that does not meet the criteria above or is no on the list of single Primary BM Units in the BSC could be a non-standard Primary BM Unit. The configuration of Non-standard Primary BM Units need to be approved by the Imbalance Settlement Group (ISG) and this results in a 60 Working Day lead time.

If you need to apply for a non-standard Primary BM Unit, you will need to complete and submit a BSCP15/4.13 form accompanied by electrical single line diagrams to Elexon explaining why you believe that the non-standard configuration is more appropriate than a standard one. Alternatively, the electrical single line diagrams can be submitted via the Self-Service Gateway (Elexon Kinnect Customer Solution) as part of the BM Unit registration. All non-standard Primary BM Units are different so please contact the Elexon Participant Management team prior to applying for a non-standard Primary BM Unit as we can provide advice on the appropriateness of your proposals, the timescales and the requirements of your application form. As a minimum, your form should contain:

A description of the Plant and Apparatus, where it connects to the Total System and the location of the Metering Equipment with reference to the electrical single line diagram; and
The Plant and Apparatus that is to be included in each of the non-standard Primary BM Unit(s) and any other standard Primary BM Units at the boundary point(s) with reference to the electrical single line diagram; and
The clause(s) of BSC Section K 3.1.2 that the non-standard Primary BM Unit does not satisfy and why; and / or
The benefits of the non-standard Primary BM Unit configuration compared to a different configuration and / or the limitations of a different configuration; and / or
Any relevant costs associated with the non-standard Primary BM Unit configuration (as opposed to a standard Primary BM Unit configuration if appropriate), e.g. metering costs, BSC Costs.

The BSCP15/4.13 form is sent to the NETSO for comment and to the ISG for decision. If the form is sent in Microsoft Word, we will remove the contact and authorised signatory information before sending it on. If the form is sent in PDF, please could you also send a copy without contact and authorised signatory information.

Please also note that as the diagrams need to be provided to ISG, the file size of an email containing diagrams should be kept below 4MB by compressing files or splitting into several files if necessary.

You can request that your application is considered in the confidential session of the ISG meeting, however the ISG encourages applications to be heard in the open session. If parts of your application are confidential, we can provide those parts to the ISG on a confidential basis (e.g. electrical single line diagrams). If you wish your whole application to be heard in the confidential session, the ISG asks that you provide the justification for this as part of your application.

Non-standard Primary BM Units are presented to the ISG for decision taking into account the views of the NETSO. The ISG consider all applications on their individual merit. There is no guarantee that a non-standard configuration will be accepted, even if a similar configuration has previously been agreed. Any Party considering a configuration of Plant and Apparatus that may not be registered as a single Primary BM Unit is encouraged to consult the NETSO and seek approval for a non-standard Primary BM Unit from the ISG early in the design of the Plant and Apparatus.

The same Plant and Apparatus cannot be contained in more than one Primary BM Unit except in the following scenarios:

where different Parties are responsible for the Import to and Export from the same Plant and Apparatus. In this scenario each Party must register a Primary BM Unit, one for the Import and one for the Export;
where all or part of the Import to the Plant and Apparatus is metered by Metering Systems registered in both CMRS and SMRS. This may be a single Metering System registered in both SMRS and CMRS at a single Boundary Point or separate Metering Systems at separate Boundary Points. The Primary BM Units may be registered by the same or different Parties; or
Power Park Modules which belong to a Switching Group.

Where a Party is responsible for both the Imports to and the Exports from Plant and Apparatus, it cannot register separate Primary BM Units for the Import to and Export from the same Plant and Apparatus measured by the same Metering System.

Permissible Configurations of Plant and Apparatus

The following configurations of Plant and Apparatus are permissible in the BSC as single Primary BM Units. This list is not exhaustive. Other configurations of Plant and Apparatus would be permissible as single Primary BM Units if the configuration meets all the criteria for a Standard Primary BM Unit set out above:

Generating Unit;
Closed Cycle Generating Turbine (CCGT) Module;
Power Park Module (PPM);
Power Station Transformers (Station Transformers)
Directly Connected Demand at a single Boundary Point Combined Offshore BM Unit (COBMU) ;
Directly connected Demand at more than one Boundary Point provided that the total Imports are equal to or less than 50MW in England and Wales, 30MW in South Scotland and 10MW in North Scotland;
Supplier (Base or Additional) Primary BM Unit;
Interconnector Primary BM Unit
Any BM Units that were determined as part of the transitional arrangements for the implementation of the British Electricity Trading and Transmission Arrangements (BETTA)
An Offshore PPM or COBMU¹⁰ and its associated Low Voltage Assets
Combination of Generating Units connected to the Total system provided that the total Exports are equal to or less than 50MW in England and Wales, 30MW in South Scotland and 10MW in North Scotland
Electricity Storage Module provided that the total Exports are equal to or less than 50MW in England and Wales, 30MW in South Scotland and 10MW in North Scotland
Hybrid Plant – PPM or combination of Generating Units plus Storage Module provided that the total Exports are equal to or less than 50MW in England and Wales, 30MW in South Scotland and 10MW in North Scotland

In addition, if there are different Parties responsible for the Import to or Export from one of the above configurations of Primary BM Units, the Import to the Plant and Apparatus can be registered in one Primary BM Unit and the Exports from the Plant and Apparatus in another Primary BM Unit as a standard configuration.

Any of the above configurations of Plant and Apparatus with associated Metering Systems registered in CMRS may have back up assets with Metering Systems registered in SMRS provided that the Registered Capacity of the Boundary Point with Metering systems registered in SMRS is less than or equal to 415V.

Configurations of Plant and Apparatus not Permissible

Any configuration of Plant and Apparatus either not on the list of permissible configurations above or not meeting the criteria for a standard Primary BM Unit is not automatically permissible as a single Primary BM Unit in the BSC. Parties may apply for a Non-Standard Primary BM Unit for any configuration of Plant and Apparatus that cannot be registered as a single Primary BM Unit, including those below.

Open Cycle Gas Turbines (OCGTs) (including CCGT conversions);
Two or more onshore PPMs controlled as a single entity;
Combination of Generating Units or Electricity Storage Module or hybrid Plant (generation plus storage) connected to the Total System, with total Exports greater than 50MW in England and Wales, 30MW in South Scotland and 10MW in North Scotland;
Directly Connected Premises at more than one Boundary Point with total Imports greater than 50MW in England and Wales, 30MW in South Scotland and 10MW in North Scotland;
Back-up assets for a CVA Primary BM Unit registered in SVA of more than 415V.

Interconnector Primary BM Units

What is an Interconnector Primary BM Unit?	Interconnector Primary BM Units allow Parties to trade over a particular Interconnector, and always come in pairs. One of the Primary BM Units is for electricity entering the System over the Interconnector (Production), and the other is for electricity being taken off the System (Consumption). Each Interconnector has many pairs of these Primary BM Units, one pair for each Party who has registered to use it. Interconnector Primary BM Units work differently to other Primary BM Units because the electricity is not metered for each Party’s Primary BM Units, but at the Interconnector Boundary. The Interconnector Administrator submits the deemed Primary BM Unit Metered Volume on the Party’s behalf. The difference between the Interconnector Metered Volume and the Primary BM Unit Metered Volumes (deemed to have been delivered) is attributed to the Interconnector Error Administrator. For more information about Interconnectors please refer to Interconnector Trading.
Do I need to do anything before registering one?	You need to Qualify as an Interconnector User to register Interconnector Primary BM Units. Visit the Market Entry page or BSCP65: Registration of Parties and Exit Procedures for more details. Before submitting the Primary BM Unit registration form, you must contact the NETSO¹¹ , to discuss your obligations and sign the necessary contractual agreements. The NETSO will give you NGC BM Unit names.
What forms do I need to fill in?	BSCP15/4.1 gives general details of the Primary BM Unit(s) you’re registering. This must be sent to the CRA 30 Working Days before the Effective From Date. BM Units can also be registered on the Self-Service Gateway (Elexon Kinnect Customer Solution).
What information do I provide on the BSCP15/4.1 form?	The NGC BM Unit ID is the ID provided by the NETSO. The Primary BM Unit ID has a prefix of ‘I_’ followed by the NGC BM Unit ID. The Primary BM Unit Type is ‘I’ for Interconnector, and the Primary BM Unit Configuration will be ‘IC’ for Interconnector Unit. For the Production Primary BM Unit (i.e. electricity flowing into the GB Transmission System), enter a positive GC, a zero DC and a ‘P’ for Production/Consumption (P/C) Flag. If you are using the Self-Service Gateway (Elexon Kinnect Customer Solution) you will need to enter the Maximum +ve QMij which will be doubled in the system to give the GCC. For the Consumption Primary BM Unit (i.e. electricity flowing from the GB Transmission System), enter a zero GC, a negative DC and a ‘C’ for the Flag. If you are using the Self-Service Gateway (Elexon Kinnect Customer Solution) you will need to enter the Maximum Negative QMij which will be doubled in the system to give the DC. In both cases, the FPN Flag is ‘Y’. Finally, enter the Interconnector ID for the Interconnector these Units are for (i.e. FRANCE, MOYLE, BRITNED, EWIC, NEMOLINK, ELECLINK, IFA2), and the date that the Primary BM Units will be effective from. Further guidance on completing this form is given in the ‘completing the BSCP15/4.1’ section below.
When do I need to submit these forms by?	You must submit the BSCP15/4.1 form at least 30 Working Days before your proposed Effective From Date.

Supplier Primary BM Units (2_Primary BM Units)

What is a Supplier Primary BM Unit?	Supplier Primary BM Units measure the amount of electricity supplied by Suppliers. Due to the high number of Supplier Meters that exist, individually identifying them all is unfeasible. Instead, all the Meters for a particular Supplier ID in a specific GSP Group are grouped into one Supplier Primary BM Unit. When a Party signs up as a Supplier, they must register 14 ‘Base’ Supply Primary BM Units, one for each GSP Group, even if they do not plan to use them all. All their supply and SVA registered embedded generation in a particular GSP Group will by default be allocated to the relevant Base Primary BM Unit. A Party can register ‘Additional’ Primary BM Units for particular sites, or grouping of Customers, within a GSP Group.
Do I need to do anything before registering one?	You need to Qualify as a Supplier to register Supplier Primary BM Units. Visit the Market Entry page or BSCP65: Registration of Parties and Exit Procedures for more details. Your Base Primary BM Units need to be registered as part of becoming a Supplier. Additional Units can be registered at the same time as Base Primary BM Units or any time after. The Effective Dates of Supplier Primary BM Units must be on or after the next eligible Market Domain Data (MDD) Go-Live Date. MDD Go-Live dates are published on the MDD Release Schedule. Before you submit the Primary BM Unit registration form, and if you wish to participate in the Balancing Mechanism (i.e. (FPN) Flag is set to Yes) you must contact the NETSO¹² , to discuss any obligations and sign the necessary contractual agreements. The NETSO will give you NGC BM Unit Id(s).
What forms do I need to fill in?	BSCP509 F509/01 is the MDD Change request form and BSCP509 Appendix 1 form MDD Entity Id 61 gives the details of the Supplier, GSP Group and BM Unit Id mapping for inclusion in Market Domain Data (MDD). These must be sent to the MDD Coordinator¹³ by the fast track CR deadline for the Version of MDD you want the changes to be included in. Please see the MDD Release Schedule for a list of these dates. BSCP15/4.1 gives general details of the Primary BM Unit(s) that you are registering. This must be sent to the CRA at least 15 Working Days before the Effective From Date which must be on or after the next eligible MDD Go-Live Date.
What information do I provide on the BSCP15/4.1 form?	The Base Primary BM Unit ID is 2__XPPPP000, where X is the relevant GSP Group letter, PPPP is your four-letter Supplier Market Participant Identifier (MPID), and 000 represents your Base Primary BM Unit. Additional Primary BM Units are numbered sequentially, i.e. 001, 002 etc, within each GSP Group. If you are submitting FPNs, the NETSO will provide you with the NGC BM Unit ID. The Primary BM Unit Type is ‘G’ if these are your Base Primary BM Units, and ‘S’ if you are registering Additional Primary BM Units. The Primary BM Unit Configuration is either ‘BB’ for a Base Unit or ‘AB’ for an Additional Unit. You need to enter the Generation and Demand Capacities (GC and DC) of each Primary BM Unit as well as the FPN Flag. You need to state the date on which the Primary BM Unit will be effective from (this must be on or after the next eligible MDD Go-Live Date). If you are using the Self-Service Gateway (Elexon Kinnect Customer Solution) you will need to enter the Maximum +ve QMij, and Maximum Negative QMij which will be doubled in the system to give the GC and the DC.
What other information is needed?	If you register the Primary BM Unit(s) as Exempt Export, refer to the Exempt Export section, which covers additional processes that you need to follow. Note that if a Supplier Primary BM Unit is registered as an Exempt Export BM Unit, it must satisfy the conditions for a standard Primary BM Unit or be approved by the Panel as a non-standard Primary BM Unit as set out in the section above, as if it were an embedded Primary BM Unit.
When do I need to submit these forms by?	You must submit the BSCP15/4.1 form at least 15 Working Days before your proposed Effective From Date which must be on or after the next eligible MDD Go-Live Date. You must submit your MDD forms in line with the MDD Release Schedule. Alternatively, this information can be completed via the Self-Service Gateway (Elexon Kinnect Customer Solution).
Is there anything else I need to do?	If you register an Additional Primary BM Unit, you need to allocate SVA MSIDs to that Additional Primary BM Unit using the process contained in BSCP503: Half Hourly Data Aggregation for SVA Metering Systems Registered in SMRS section 3.5, otherwise these Primary BM Units will remain in the Base Supplier Primary BM Unit. If you wish to use an Additional Primary BM Unit for Balancing Services, you need to allocate SVA MSIDs to it using the process contained in BSCP602: SVA Metering System Balancing Services Register section 2.1
Are there any other options?	If you wish to register an Additional Primary BM Unit in every GSP Group you may wish to register an additional Market Participant Identifier (MPID) under your Trading Party Id instead¹⁴ . This would have the effect of creating another set of 14 Supplier Primary BM Units under the new MPID and which would carry no extra BSC Charges. Creating a set of 14 Additional BM Units, one in each GSP Group would cost £840 in BSC Charges (see the Schedule of Main and SVA Specified Charges). If registering an additional MPID you should consider the impact that splitting your portfolio may have on your reporting e.g. DTN, PARMs. To register an additional MPID you need to submit forms BSCP65/05, BSCP15/4.1, BSCP509 F509/01 MDD Change request form and BSCP509 Appendix 1 form MDD Entity Ids 1, 45 and 61. The Process is described in BSCP65 Section 4.8 and BSCP15 Section 3.3

Supplier Primary BM Units (C_Primary BM Units) for EMR

Guidance on the registration of Additional Supplier Primary BM Units for the purpose of allocating Contracts for Difference (CfD) Assets can be found in the Registration of Primary BM Units for EMR guidance.

Secondary BM Units (V_Secondary BM Units)

What is a Secondary BM Unit?	Secondary BM Units record the amount of Balancing Energy provided by Virtual Lead Parties to the NETSO as a Balancing Services Provider.
Do I need to do anything before registering one?	You need to Qualify as a Virtual Lead Party to register Secondary BM Units. Visit the Market Entry page or BSCP65: Registration of Parties and Exit Procedures for more details. Before submitting the Secondary BM Unit registration form, you must contact the NETSO¹⁵ , to discuss your obligations and sign the necessary contractual agreements. The NETSO will give you NGC BM Unit Id(s).
What forms do I need to fill in?	BSCP15/4.14 gives general details of the Secondary BM Unit(s) you are registering. This must be sent to the CRA at least 15 Working Days before the Effective From Date. BM Units can also be registered on the Self-Service Gateway (Elexon Kinnect Customer Solution).
What information do I provide on the BSCP15/4.14 form?	The Secondary BM Unit ID is V__XPPPP000, where X is the relevant GSP Group letter, PPPP is your four-letter Market Participant Identifier, and 00n where n are numbered sequentially, i.e. 001, 002 etc, within each GSP Group. The NETSO will provide you with the NGC BM Unit ID. You need to state the date on which the Secondary BM Unit will be effective from.
When do I need to submit these forms by?	You must submit the BSCP15/4.14 form at least 15 Working Days before your proposed Effective From Date.
Is there anything else I need to do?	You need to allocate SVA MSIDs to the Secondary BM Unit using the process contained in BSCP602: SVA Metering System Balancing Services Register section 2.1.

Exempt Export Primary BM Units

What is an Exempt Export Primary BM Unit?	Some Generating Plants are ‘Exemptable’, which means that the Lead Party doesn’t need a Generation Licence. If the Lead Party of an Exemptable Generating Plant applies for and is granted exempt export status under the BSC, it can receive Embedded Benefits (if embedded) and declare its own P/C flag (embedded or directly connected).
What is the benefit of being Exempt Export?	For embedded Plant, depending on its the size, the benefits of being Exemptable apply to some or all of: Transmission Network Use of System (TNUoS) Charges; Balancing Services Use of System (BSUoS) Charges; and Transmission Losses. Further information can be found in the Embedded Generation and Embedded Benefits guidance. For Exempt Export Primary BM Units, you declare your own P/C Flag, which is then fixed. You are able to change your P/C flag as required but it will always take the flag that you choose.
How can I nominate a Primary BM Unit as Exemptable?	Some generators meet the conditions of a Statutory Instrument exempting them from the requirement to hold a Generation Licence. There are class exemptions which apply to all generators that meet the conditions and individual exemptions for other generators. More information can be found on the Department of Business, Energy and Industrial Strategy website. If you wish for your Primary BM Unit to be treated as exemptable under the BSC, you must apply for this status. You can do this with the initial Primary BM Unit Registration, or separately at a later date. Note that a Primary BM Unit associated with SVA registered Metering and Exempt Export status can only contain the Exemptable Generating Plant for which it is being registered, it cannot contain additional generation or demand. A Base Primary BM Unit can have an Exempt Export status, if it contains a single Exemptable Generating Plant. A Party that wishes to flag a Base Primary BM Unit as Exempt Export Status needs to ensure that they do not allocate any other Generation or Demand to that Primary BM Unit. Alternatively an Additional Supplier Primary BM Unit can be registered and flagged as Exempt Export Status to contain an Exemptable Generating Plant. Note that an Exemptable Generating Plant does not have to be included in an Exempt Export Primary BM Unit under the BSC; however exemptable benefits can only be applied to Exempt Export Primary BM Units.
What forms do I need to fill in?	For CVA Primary BM Units: You must submit BSCP15/4.5A to apply for the Exempt Export status for a CVA-registered Primary BM Unit and to choose the P/C Flag to Elexon at least 20 Working Days before the required date. Alternatively, this information can be completed via the Self-Service Gateway (Elexon Kinnect Customer Solution).	For SVA Primary BM Units: You must submit BSCP15/4.9A to apply for the Exempt Export status for an SVA-registered Primary BM Unit and to choose the P/C Flag to Elexon¹⁶ at least 20 Working Days before the required date. Alternatively, this information can be completed via the Self-Service Gateway (Elexon Kinnect Customer Solution). If registering an Additional Primary BM Unit, you will also need to allocate the Metering System associated with the Exemptable Generating Plant to the Additional Primary BM Unit via BSCP503.
What other information is needed?	For CVA Primary BM Units: We need to check whether the Primary BM Unit is eligible to be Exemptable. Once Elexon has verified this, we will confirm or reject your application.	For SVA Primary BM Units: All you need to do is submit a BSCP15/4.9A form to us, and Elexon will confirm the status.
How do I change the P/C Flag?	Exempt Export Primary BM Units must elect their own P/C Flag when they are first registered as exemptable using the BSCP15/4.5A (CVA) or BSCP15/4.9A (SVA) form. If the Lead Party wishes to change the P/C Flag of an Exempt Export Primary BM Unit, the Lead Party must send the CRA and Elexon a BSCP15/4.8 form stating whether they will have a Production or Consumption Flag. Alternatively, this information can be completed via the Self-Service Gateway (Elexon Kinnect Customer Solution).

Trading Units

A Trading Unit is a Primary BM Unit or a combination of Primary BM Units. A ‘Sole’ Trading Unit is a Trading Unit containing one Primary BM Unit. There are 14 Base Trading Units, one for each GSP Group.

Being in a Trading Unit allows all the Primary BM Units to be treated the same for:

Transmission Loss Multipliers (TLMs);
Production/Consumption flag;
Certain BSC costs; and
Balancing Services Use of System (BSUoS) charges.

By default, all directly connected (T_) and embedded (E_) Primary BM Units are sole Trading Units. If your site consists of more than one Primary BM Unit then you may wish to set up a Trading Unit for the overall site.

By default, all Supplier and SVA Exempt Export Primary BM Units will be added to the Base Trading Unit. If you do not want your SVA Exempt Export Primary BM Unit to be part of the relevant Base Trading Unit you need to apply for it to be part of a different Trading Unit.

Further information on Trading Units can be found on the Trading Units section of the BSC Website, in BSCP31: Registration of Trading Units or by contacting trading.unit@elexon.co.uk.

Switching Groups

Some Offshore and onshore Power Park Modules (PPM) can be moved between Primary BM Units. You can set the relevant Primary BM Units up in a Switching Group, and opt to run the relevant PPM in any of the Primary BM Units within that Switching Group. To set this up, you must enter the relevant details in the table at the end of the BSCP15/4.1 form as well as submitting the applicable Aggregation Rules (BSCP75) for all the possible running configurations when you are registering the Aggregation Rules.

Completing form BSCP15/4.1 Registration of Primary BM Unit for a CVA Metering System

Please ensure that you are completing the most up to date version of the BSCP form by obtaining a new form from the BSC website for each new registration. The forms can be found under the BSCP section of the website. Please note that forms are directly below a given BSCP (as per the following example):

Participant Details

Please ensure that all of the Participant Details sections are completed, including the Party Id.

Authorised Signature

If the form is emailed, it must be emailed from the Authorised Signatories’ email address. The Authorised Signature can be left blank but the password must be completed. If the form is faxed or posted, the Authorised Signature and Password must be completed.

Primary BM Unit Registration Details

Primary BM Unit Registration Details

Primary BM Unit Id

Primary BM Unit Name (Max 30 Characters)

NG BM Unit ID

Primary BM Unit Type

Primary BM Unit Configuration

GSP Group Id

GC (MW)

DC (MW)

Inter-connector Primary BM Unit P/ C Flag

FPN Flag (Y/N)

Exempt Export (optional)

Inter-connector Id

EFD

Primary BM Unit Id – For directly connected, embedded and Interconnector Primary BM Units, if you have a NGC BM Unit Id this is either T_ (directly connected), E_ (embedded) or I_(Interconnector) followed by your NCG BM Unit Id. E.g. if you have a directly connected Unit with the NETSO where NGC BM Unit Id is ABCD-1, your BSC Primary BM Unit Id will be T_ABCD-1.

For embedded Primary BM Units without a NGC BM Unit Id, your Primary BM Unit Id needs to start ‘E_’. You can choose the rest of the Id up to a limit of 11 characters in total (i.e. including ‘E_’).

For Supplier Primary BM Units, the Base Primary BM Unit ID is 2__XPPPP000, where X is the relevant GSP Group letter, PPPP is your four-letter Supplier Market Participant Identifier (MPID), and 000 represents your Base Primary BM Unit. Additional Primary BM Units are numbered sequentially, i.e. 001, 002 etc., within each GSP Group.

Primary BM Unit Name – this is a free text field to identify the name of your Primary BM Unit, up to a limit of 30 characters.

NGC BM Unit Id – BSC Primary BM Units need to be registered with the NETSO and have a corresponding NGC BM Unit Id if their Generation or Demand Capacity is at or above 50MW in England and Wales, 30MW in South Scotland or 10MW in North Scotland. Below these limits you can choose whether or not you register a NCG BM Unit, although you will need to if you have a Bilateral Embedded Generation Agreement (BEGA) with the NETSO. Interconnector Primary BM Units always need to be registered with the NETSO. Your NGC BM Unit Id will be provided by the NETSO when you register your BM Unit with them. Please contact bmu.registration@nationalgrideso.com and transmissionconnections@nationalgrideso.com for information on registering your BM Unit with the NETSO and how to obtain a NGC BM Unit Id.

Primary BM Unit Type – please enter one of the following letters depending on your Primary BM Unit type:

T – Directly Connected Primary BM Unit, connected to the Transmission System;
E – Embedded Primary BM Unit, connected to a Distribution System;
I – Interconnector Primary BM Unit;
G – Base Supplier Primary BM Unit; or
S – Additional Supplier Primary BM Unit.

Primary BM Unit configuration - please enter one of the following letters depending on your Primary BM Unit configuration:

CCGT – Combined Cycle Gas Turbine registered in Central Meter Registration Service (CMRS);
PPM – a single Power Park Module registered in CMRS;
COBMU – a Combined Offshore BM Unit comprising 2 or more Offshore Power Park Modules registered in CMRS. This configuration must be agreed by the NETSO;
DC – Directly Connected Circuit at Customer (Supplied by BSC Party) Premises (there must be one Primary BM Unit for each circuit connected to the Transmission System);
DC+ – Directly Connected Circuit at Customer (Supplied by BSC Party) Premises through more than one Boundary Point. Total demand must be less than 50MW in England and Wales, 30 MW in South Scotland and 10 MW in North Scotland;
IC – Interconnector Primary BM Unit;
BB – Supplier Base Primary BM Unit. There will be 14 of these on the form, one for each GSP Group;
AB – Additional Primary BM Unit;
OPPM+ - Offshore PPM plus related Imports at separate Boundary Points;
COBMU+ - COBMU plus related Imports at separate Boundary Points;
MC – Meets criteria in BSC K3.1.2. If meets criteria is selected, you need to complete the table in the form to confirm you meet the five criteria for a Primary BM Unit detailed in Section K 3.1.2 of the BSC; or
NS – Non-standard Primary BM Unit. If non-standard Primary BM Unit is selected, you also need to submit a BSCP15/4.13 form.

GSP Group Id – This only needs to be completed for embedded and Supplier Primary BM Units, the GSP Group that the Primary BM Unit contributes to. For all other Primary BM Units leave this blank.

GC – Generation Capacity which is the maximum expected net Generation for the Primary BM Unit in its first BSC Season.

DC – Demand Capacity which is the maximum expected net Demand for the Primary BM Unit in its first BSC Season.

Interconnector Primary BM Unit P/C Flag – This only needs to be completed for Interconnector Primary BM Units. For the Primary BM Unit with a positive GC and a zero DC, enter a ‘P’ for P/C Flag. For the Primary BM Unit with a zero GC and a negative DC enter a ‘C’ for the Flag. For all other Primary BM Units leave this blank.

FPN Flag – This needs to be ‘Y’ for any Primary BM Unit with a NGC BM Unit Id and ‘N’ for any Primary BM Units without a NGC BM Unit Id.

Exempt Export – If your Plant and Apparatus is exempt from the requirement to hold a Generation Licence, you may wish to flag your Primary BM Unit as Exempt Export under the BSC, enter ‘Y’ and submit either a BSCP15/4.5A (for directly connected or embedded Primary BM Units) or BSCP15/4.9A (For Base and Additional Primary Supplier BM Units) form along with your BSCP15/4.1 form.

Inter-connector Id - This only needs to be completed for Interconnector Primary BM Units and should be one of the following:

FRANCE;
MOYLE;
BRITNED;
EWIC;
NEMOLINK
ELECLINK; or
IFA2

EFD – This is the best estimate of the earliest Effective From Date for the Primary BM Unit. If the date moves back from the one submitted on the BSCP15/4.1 form, there is no need to submit another form. However, if the date moves forward, you will need to submit another form.

Electrical Single Line Diagram

For all registrations of directly connected and embedded Primary BM Units, please ensure that you submit electrical single line diagram(s) showing:

the location of the Metering Equipment, in particular the Settlement current and voltage transformers (CTs/VTs) and CT/VT ratios; and
any existing Boundary Points and/ or System Connection Points at or near the proposed Boundary Point(s); and
any back up SVA connection and interlocking arrangements.

Please tick the box on the form to show that the diagram has been submitted.

Primary BM Unit meeting criteria

If your Primary BM Unit meets the criteria set out in section K3.1.2 of the BSC, you need to confirm that it meets each criteria using the table in the BSCP15/4.1 form.

Fuel Type (Directly Connected or Embedded Primary BM Units) – for use in calculation of CALF values

Please indicate the fuel type for the Primary BM Unit from the list contained in the table.

Primary BM Unit and Associated CVA Metering Systems

If this is a registration of an embedded or directly connected Primary BM Unit and you already have a CVA Metering System Identifier (MSID)¹⁷ , please enter it here. If you do not have a MSID, please leave this section blank. For all other registrations, leave this section blank.

MPAN Mapping details

If this is a Registration Transfer from SVA to CVA in accordance with BSCP68, please enter the MPANs related to the SVA registration here with the Effective To Date. For all other registrations, leave this section blank.

Primary BM Unit Group Details

This section in BSCP15 is no longer needed as the corresponding section of the BSC was removed by Approved Modification P394. Leave this section blank.

Switching Groups

If a Power Park Module could be part of more than one Primary BM Unit, then each of the Primary BM Units that it could be part of needs to be included here as a Switching Group, even if you have no intension of switching that Power Park Module between Primary BM Units. You form may have more than one Switching Group if there are multiple Power Park Modules that could belong to more than one Primary BM Unit.

Need more information?

For more information please contact the BSC Service Desk at bscservicedesk@cgi.com or call 0370 010 6950.

You can find out more here:

Intellectual Property Rights, Copyright and Disclaimer

The copyright and other intellectual property rights in this document are vested in Elexon or appear with the consent of the copyright owner. These materials are made available for you for the purposes of your participation in the electricity industry. If you have an interest in the electricity industry, you may view, download, copy, distribute, modify, transmit, publish, sell or create derivative works (in whatever format) from this document or in other cases use for personal academic or other non-commercial purposes. All copyright and other proprietary notices contained in the document must be retained on any copy you make.

All other rights of the copyright owner not expressly dealt with above are reserved.

No representation, warranty or guarantee is made that the information in this document is accurate or complete. While care is taken in the collection and provision of this information, Elexon Limited shall not be liable for any errors, omissions, misstatements or mistakes in any information or damages resulting from the use of this information or action taken in reliance on it.

1 Bmu.registration@nationalgrideso.com and transmissionconnections@nationalgrideso.com

2 neta@imserv.com

3 A Metering System ID (MSID) for your BM Unit can be reserved by contacting the CRA.

4 The Aggregation Rules guidance explains how to write your Aggregation Rules.

5 Bmu.registration@nationalgrideso.com and transmissionconnections@nationalgrideso.com

6 neta@imserv.com

7 A Metering System ID (MSID) for your BM Unit can be reserved by contacting the CRA. If you are registering both Export and Import relating to the site, then you will need to check with the LDSO if they intend to apply a separate CVA Line Loss Factors (LLFs) to the Export and to the Import – if so, then you will need two MSIDs (one for Export, one for Import).

8 The Aggregation Rules guidance explains how to write your Aggregation Rules.

9 Small Power Station is defined in the Grid Code as a Power Station with a Registered Capacity of less than 50MW in England and Wales, less than 30MW in South Scotland and less than 10MW in North Scotland and Offshore.

10 The NETSO must agree that two or more Power Park Modules can be combined into a Combined Offshore BM Unit.

11 Bmu.registration@nationalgrideso.com and transmissionconnections@nationalgrideso.com

12 Bmu.registration@nationalgrideso.com and transmissionconnections@nationalgrideso.com

13 mddc@elexon.co.uk

14 Note that if you have a contact with the NETSO to participate in the Balancing Market with these BM Unit, it may require you to register Additional BM Units as opposed to an additional MPID.

15 Bmu.registration@nationalgrideso.com and transmissionconnections@nationalgrideso.com

16 Bm.unit@elexon.co.uk

17 A Metering System ID (MSID) for your BM Unit can be reserved by contacting the CRA.

CONTENTS

BM Units – Registration of Balancing Mechanism (BM) Units

What is a BM Unit?

Types of BM Units

Directly Connected Primary BM Units

Embedded Primary BM Units

Standard and Non-Standard Primary BM Unit Configuration

0.0.1 the Registered Capacity of the Boundary Point measured by the Metering System(s) registered in SMRS is equal to or less than the limit determined by the Panel, currently 415V;

0.0.2 the Plant and Apparatus cannot Export through the Metering System registered in SMRS; and

0.0.3 there are measures in place to prevent instantaneous flow through of electricity:

Permissible Configurations of Plant and Apparatus

Configurations of Plant and Apparatus not Permissible

Interconnector Primary BM Units

Supplier Primary BM Units (2_Primary BM Units)

Supplier Primary BM Units (C_Primary BM Units) for EMR

Secondary BM Units (V_Secondary BM Units)

Exempt Export Primary BM Units

Trading Units

Switching Groups

Completing form BSCP15/4.1 Registration of Primary BM Unit for a CVA Metering System

Participant Details

Authorised Signature

Primary BM Unit Registration Details

Electrical Single Line Diagram

Primary BM Unit meeting criteria

Fuel Type (Directly Connected or Embedded Primary BM Units) – for use in calculation of CALF values

Primary BM Unit and Associated CVA Metering Systems

MPAN Mapping details

Primary BM Unit Group Details

Switching Groups

Need more information?