Balancing Mechanism Units

Balancing Mechanism (BM) Units are used as units of trade within the Balancing Mechanism. Each BM Unit accounts for a collection of plant and/or apparatus, and is considered the smallest grouping that can be independently controlled. As a result, most BM Units contain either a generating unit or a collection of consumption meters. Any energy produced or consumed by the contents of a BM Unit is accredited to that BM Unit.

BM Units can be classed as either Primary or Secondary BM Units. There are several types of BM Unit, each representing different aspects of the system. They are: Directly Connected; Embedded; Interconnector; Supplier; Secondary; and Miscellaneous.

Primary BM Units

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

Secondary BM Units can only be registered by Virtual Lead Parties (VLPs).  Supplier Volume Allocation (SVA) Half Hourly (HH) metered generation and / or demand equipment within a single 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). 

Systems Connection Points 

A Systems Connection Point is a point of connection between two or more Systems excluding points of connection between Distribution Systems in the same GSP Group or a point of connection between Offshore Transmission System User Assets and the Transmission System. There are three types of Systems Connection Points:

  • Grid Supply Points (GSPs) – these are points of connection between the Transmission System and a Distribution System
  • Offshore Transmission Connection Point (OTCP) – these are a GSP where the Systems Connection Point is between a Distribution System and an Offshore Transmission System. Note, at an OTCP the Metering System is registered by NETSO as opposed to the LDSO
  • Distribution Systems Connection Points (DSCPs) – these are points of connection between two Distribution Systems


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