If the BM Unit’s P/C Status is Production, we allocate its Metered Volume to the Lead Party’s Production Energy Account. If its P/C Status is Consumption, we allocate its Metered Volume to the Lead Party’s Consumption Energy Account.

2. What is the P/C Flag?

The P/C Flag is a setting within the central BSC Systems for each BM Unit, which dictates how the systems determine its P/C Status.

There are three possible settings for a BM Unit’s P/C Flag:

Production (P);
Consumption (C); or
Null (blank).

The central BSC Systems apply the rule that:

if a BM Unit’s P/C Flag is set to P, then its P/C Status is fixed as Production and cannot change unless the P/C Flag setting changes;
if a BM Unit’s P/C Flag is set to C, then its P/C Status is fixed as Consumption and cannot change unless the P/C Flag setting changes; and
if a BM Unit’s P/C Flag is Null, then (with some exceptions which we explain in the next section) its P/C Status is determined dynamically – this means that it may be either Production or Consumption for any given Settlement Day, and can change on a daily basis.

3. How do we determine a BM Unit’s P/C Flat setting and P/C Status?

This depends on the type of BM Unit.

The table below summarises the different types of BM Unit and the rules affecting their P/C Status. The rest of this section explains in detail how we determine the P/C Flag setting and P/C Status for each type of BM Unit.

Type of BM Unit	Identified in central BSC Systems by:	Description	P/C Status is:
Interconnector Primary BM Unit	I_ prefix in BM Unit ID BM Unit type I	Each Party using an Interconnector (an ‘Interconnector User’) has two Primary BM Units for that Interconnector, one Production (import into GB) and one Consumption (export from GB).	Each BM Unit is fixed as either P or C by the central BSC Systems and cannot be changed
Supplier Primary BM Unit	2_prefix in BM Unit ID C_prefix in BM Unit ID BM Unit type G (Base BM Unit) BM Unit type S (Additional BM Unit)	Each Supplier has 14 Base Primary BM Units – one for each Grid Supply Point (GSP) Group. Suppliers can also optionally register one or more Additional Primary BM Units for a GSP Group. ‘Supplier Primary BM Units’ is the BSC’s collective term for Base Primary BM Units and Additional Primary BM Units.	Fixed as C by the central BSC Systems and cannot be changed unless also an Exempt Export BM Unit (see below).
Exempt Export BM Unit	Exempt Export Flag set to ‘True’ (T) Can be any BM Unit prefix or type with the exception of I or V	A Primary BM Unit relating to an Exemptable Generating Plant¹. Can be a Supplier Primary BM Unit with embedded generation or a ‘generation’ Primary BM Unit. To have an Exempt Export BM Unit, the Lead Party must apply for Exemptable status using BSC Procedure 15 (BSCP15): BM Unit Registration and elect their P/C Flag accordingly.	Fixed by the Lead Party and can only be changed by them.
Storage BM Unit	Storage BM Unit Flag set to ‘True’ (T) Can be T_ or E_ prefix in BM Unit ID BM Unit type T or E	A Primary BM Unit consisting solely of Electricity Storage Module(s), as defined in the Grid Code. Can be an ‘embedded’ generator connected to a Distribution System, or a generator directly connected to the Transmission System To have a Storage BM Unit, the Lead Party must apply for to be classified as a Storage BM Unit using BSC Procedure 15 (BSCP15): BM Unit Registration, and elect their P/C Flag accordingly.	Fixed by the Lead Party and can only be changed by them.
‘Generation’ Primary BM Unit	E_prefix in BM Unit ID T_prefix in BM Unit ID M_prefix in BM Unit ID BM Unit type E BM Unit type T	Although the BSC doesn’t define the term ‘generation’ Primary BM Unit, we have several different types of Primary BM Unit to represent generation equipment: E_ means an ‘embedded’ generator connected to a Distribution System; T_ means a generator directly connected to the Transmission System²; and M_ refers to legacy miscellaneous Type T equipment.³	Not fixed – the central BSC Systems calculate this dynamically and it can change on a daily basis.
‘Directly Connected Demand’ Primary BM Unit	T_prefix in BM Unit ID M_prefix in BM Unit ID BM Unit type T	Although the BSC doesn’t define the term ‘directly connected demand’ Primary BM Unit, the are some large demand assets which are directly connected to the Transmission System which only or mainly import electricity from the Transmission System.	Not fixed – the central BSC Systems calculate this dynamically and it can change on a daily basis.
Secondary BM Unit	V_ prefix in BM Unit ID BM Unit type V Registered by a Virtual Lead Party (VLP) or an Asset Metering VLP (AMVLP) who does not have the Virtual Trading Party (VTP) role.	A Secondary BM Unit used by a third party to provide Balancing Services to the NETSO instead of the Supplier performing this role.	Fixed by the VLP/AMVLP and can only be changed by them. If you are a VLP and / or AMVLP only, you should enter a C.
Trading Secondary BM Unit	V_ prefix in BM Unit ID BM Unit type V Registered by a VTP who may also have a VLP and / or AMVLP role.	A Secondary BM Unit used by a third party to trade in the Wholesale Energy Market (and also provide Balancing services to the NETSO if the third Party also has the VLP and /or AMVLP role) instead of the Supplier performing this role.	Not fixed – the central BSC Systems calculate this dynamically and it can change on a daily basis.

See our separate BM Units Guidance for more on BM Units. ‘Lead Party’ means the BSC Party who is responsible for any energy flows associated with the BM Unit.⁴

Interconnector Primary BM Units

The P/C Flag settings, and therefore the P/C Status, of Interconnector Primary BM Units are fixed by the central BSC Systems and cannot be changed.

We assign Interconnector Primary BM Units in pairs, and each Party has a different pair for each Interconnector it uses:

One of these two Primary BM Units has a fixed P Flag, and accounts for energy entering GB over the Interconnector. Its P/C Status is therefore always Production.
The other Primary BM Unit has a fixed C Flag, and accounts for energy leaving GB. Its P/C Status is always Consumption.

Supplier Primary BM Units

Non-Exempt Export Supplier Primary BM Units always have a P/C Flag of Null. Despite this, they always have a fixed P/C Status of Consumption which cannot be changed (i.e. they are always Consumption Primary BM Units).

This is because they are part of a Base Trading Unit.

There are 14 Base Trading Units, one for each GSP Group. All Primary BM Units in a Base Trading Unit have a fixed P/C Status of Consumption, with the exception of any Exempt Export BM Units in the Base Trading Unit which choose to have a fixed P/C Status of Production by setting their P/C Flag to P.

The central BSC Systems will set a BM Unit’s P/C Status to Consumption if:

the BM Unit is part of a Base Trading Unit (i.e. its Base Trading Unit Flag is ‘True’ (T)); and
the BM Unit’s P/C Flag is ‘Null’.

All Supplier Primary BM Units (i.e. 2_ & C_ types G and S) which are not Exempt Export (i.e. have an Exempt Export Flag of ‘False’) are always part of the Base Trading Unit for the relevant GSP Group. They therefore have a Base Trading Unit Flag of ‘True’.

A Base Trading Unit may also contain embedded (E_) Exempt Export BM Units but not transmission-connected (T_) Exempt Export BM Units or any other type of BM Unit.

See our separate Trading Units Guidance and BSCP31 for more about the different types of Trading Unit.

Exempt Export BM Units

The Lead Party of an Exempt Export BM Unit must choose to set the Primary BM Unit’s P/C Flag to either P or C. In other words, it must choose a fixed P/C Status of either Production or Consumption for the Primary BM Unit.

The Lead Party for the Primary BM Unit:

must choose its P/C Flag setting when applying for Exemptable Generating Plant status, using either the Elexon Kinnect Customer Solution or completing and sending the BSCP15/4.5 form or BSCP15/4.9 form to bm.unit@elexon.co.uk; and
can later change its P/C Flag and thereby its P/C Status (from P to C, or from C to P), by using either the Elexon Kinnect Customer Solution or completing and sending the BSCP15/4.8 form to neta@imserv.com.

The Lead Party can change the Primary BM Unit’s P/C Flag on a daily basis, subject to the minimum notice period in BSCP15.

If the Primary BM Unit’s Exempt Export status is terminated under BSCP15, the central BSC Systems will reset its P/C Flag as detailed in the table above at the same time they reset its Exempt Export Flag to ‘False’ (F).

Storage BM Units

The Lead Party of a Storage BM Unit must choose to set the Primary BM Unit’s P/C Flag to either P or C. In other words, it must choose a fixed P/C Status of either Production or Consumption for the Primary BM Unit.

The Lead Party for the Primary BM Unit:

must choose its P/C Flag setting when applying for the first time for a Storage BM Unit Plant status, using either the Elexon Kinnect Customer Solution or completing and sending the BSCP15/4.1 to neta@imserv.com; and
can later change its P/C Flag and thereby its P/C Status (from P to C, or from C to P), by using either the Elexon Kinnect Customer Solution or completing and sending the BSCP15/4.8 form to neta@imserv.com.

The Lead Party can change the Primary BM Unit’s P/C Flag on a daily basis, subject to the minimum notice period in BSCP15.

If the Primary BM Unit’s Storage BM Unit classification is terminated under BSCP15, the central BSC Systems will reset its P/C Flag as detailed in the table above at the same time they reset its Storage BM Unit Flag to ‘False’ (F).

Secondary BM Units associated with a VLP and / or AMVLP (and not a VTP)

The VLP or AMVLP of a Secondary BM Unit must choose to set the Secondary BM Unit’s P/C Flag to either P or C. In other words, it must choose a fixed P/C Status of either Production or Consumption for the Secondary BM Unit.

The Lead Party for the Secondary BM Unit:

must choose its P/C Flag setting when applying for the first time for a Secondary BM Unit, using either the Elexon Kinnect Customer Solution or completing and sending the BSCP15/4.14 form to neta@imserv.com; and
can later change its P/C Flag and thereby its P/C Status (from P to C, or from C to P), by using either the Elexon Kinnect Customer Solution, or completing and sending the BSCP15/4.8 form to neta@imserv.com.

Note that if you are a VLP and / or AMVLP only, you should enter a ‘C’.

The Lead Party can change the Secondary BM Unit’s P/C Flag on a daily basis, subject to the minimum notice period in BSCP15.

All other BM Units

If a BM Unit is a generation Primary BM Unit that is not an Exempt Export or Storage BM Unit, a directly connected demand Primary BM Unit or a Trading Secondary BM Unit registered by a VTP, then its P/C Flag will be Null. Because it is not part of a Base Trading Unit, the central BSC Systems will determine the BM Unit’s P/C Status dynamically and it can change on a daily basis.

The central BSC Systems will determine a BM Unit’s P/C Status dynamically if

the BM Unit is not part of a Base Trading Unit (i.e. its Base Trading Unit Flag is ‘False’); and
the BM Unit’s P/C Flag is ‘Null’.

For generation and directly connected demand Primary BM Units, this means that the Primary BM Unit’s P/C Status will be determined by summing the Relevant Capacities of all the Primary BM Units in its Trading Unit, including the Primary BM Unit⁵ itself. For Trading Secondary BM Units registered by a VTP, this means that the Secondary BM Unit’s P/C Status will be determined by the Relevant Capacity of the Trading Secondary BM Unit.

A BM Unit’s Relevant Capacity depends in turn on its Generation Capacity (GC, a positive or zero value) and Demand Capacity (DC, a negative or zero value).⁶

A BM Unit’s Relevant Capacity is:

its GC value, if its GC+DC is greater than zero; or
its DC value, if its GC+DC is less than or equal to zero.

A BM Unit with a ‘False’ Base Trading Unit Flag and a ‘Null’ P/C Flag will have a P/C Status of:

Production, if the sum of all the Primary BM Unit Relevant Capacities in its Trading Unit or Secondary BM Unit is greater than zero; or
Consumption, if the sum of all the Primary BM Unit Relevant Capacities in its Trading Unit or Secondary BM Unit is less than or equal to zero.

If the Primary BM Unit is a Sole Trading Unit on its own or a Secondary BM Unit, then only its own GC and DC values affect its P/C Status.

However, if a Primary BM Unit is part of a Trading Unit with one or more other Primary BM Units then the GC and DC values of these other Primary BM Unit(s) will also affect its P/C Status. A Primary BM Unit in a Trading Unit with other Primary BM Units may therefore have a Production P/C Status even if its individual Relevant Capacity is its DC value, or a Consumption P/C Status even if its individual Relevant Capacity is its GC value.

The central BSC Systems re-determine the Primary BM Unit’s P/C Status whenever:

the Primary BM Unit joins or leaves a Trading Unit;
another Primary BM Unit joins or leaves its Trading Unit; and/or
the GC and/or DC value for the Primary BM Unit, or for any other Primary BM Unit in its Trading Unit, changes.⁷

The Primary BM Unit’s P/C Status can therefore change on a daily basis.

An example of a dynamically-determined P/C Status (Null P/C Flag, F Base TU Flag):

Primary BM Unit	GC (MW)	DC (MW)	Relevant Capacity	Sum of Relevant Capacities means:
T_GEN-1	75	-5	75	P/C Status is P
T_GEN-2	25	-5	25
T_DEM-1	5	-30	-30
Sum of Relevant Capacities			70

This Trading Unit contains three Primary BM Units, none of which are Interconnector Primary BM Units, Exempt Export Primary BM Units or Supplier Primary BM Units (i.e. all three Primary BM Units have ‘Null’ P/C Flags, ‘False’ Exempt Export Flags and ‘False’ Base Trading Unit Flags).

There are two Generating Units and a demand unit. We calculate the Relevant Capacity of each Primary BM Unit and sum these values.

In the example above, the total is 70 so all three Primary BM Units have a P/C Status of Production even though the demand unit is consuming.

However, the GC value of one of the Generating Units then changes. The new total in the example below is -10, so the P/C Status of all three Primary BM Units (including the remaining Generating Unit) changes to Consumption.

Primary BM Unit	GC (MW)	DC (MW)	Relevant Capacity	Sum of Relevant Capacities means:
T_GEN-1	0	-5	-5	P/C Status is C
T_GEN-2	25	-5	25
T_DEM-1	5	-30	-30
Sum of Relevant Capacities			-10

4. Why does P/C Status matter?

P/C Status has three important effects on a Party:

it determines to which of a Lead Party’s Energy Accounts the BSC Central Systems allocate the BM Unit’s Metered Volume for the purpose of calculating imbalance charges;
it restricts Lead Parties’ ability to reassign the BM Unit’s Metered Volumes to another Subsidiary Party through the use of Metered Volume Reallocation Notifications, which can affect both Parties’ imbalance charges; and
it affects how we estimate the Lead Party’s Energy Indebtedness, which we use to decide whether it’s lodged enough financial credit to cover its imbalance charges.

Effect on Energy Account imbalance

To avoid imbalances, Parties try to match their volumes of contracted and metered energy. Parties must financially settle any differences (or ‘imbalances’) between these using the Imbalance Price.

See our separate Beginner’s Guide to the electricity trading arrangements, for more about how we work out energy imbalances and apply imbalance charges.

Effect on Metered Volume Reallocation Notifications

A BM Unit’s P/C Status restricts its Lead Party’s ability to use Metered Volume Reallocation Notifications (MVRNs).

Contract Trading Parties⁸ can use ECVNs to trade energy volumes to/from the Energy Account of another Contract Trading Party, or between a Contract Trading Party’s own two Energy Accounts.

The Lead Party for a Primary BM Unit can also reallocate some or all of the BM Unit’s Credited Energy Volume to the Energy Account of another Contract Trading Party (the ‘Subsidiary Party’) through an MVRN. However, MVRNs can only reallocate energy:

from a Production BM Unit to a Production Energy Account; or
from a Consumption BM Unit to a Consumption Energy Account.

If a BM Unit’s P/C Status changes, the BSC Central Systems automatically give any existing MVRNs for that BM Unit an end-date of the day before the change. This means that we will subsequently allocate the entire BM Unit’s Credited Energy Volume to the Lead Party. This potentially leaves both the Lead Party and Subsidiary Party in imbalance if they are unaware of the change and do not have energy contracts in place to balance their positions.

See our separate Volume Notifications Guidance for more about MVRNs.

Effect on Energy Indebtedness

The BSC’s Credit Cover calculation needs a way to estimate Parties’ accrued Energy Indebtedness before we know their actual BM Unit Metered Volumes. It does this by using Final Physical Notifications (FPNs) for some types of BM Unit. These BM Units are deemed as Credit Qualifying BM Units.

For other BM Units, the calculation uses either their GC or DC value as part of an estimation. These BM Units are deemed non-Credit Qualifying BM Units.

For Primary BM Units that are not Credit Qualifying BM Units or Interconnector Primary BM Units, or Trading Secondary BM Units, their P/C Status therefore affects how we calculate their Energy Indebtedness. This is because the estimate If a Primary BM Unit’s P/C Status changes, the Lead Party should therefore ensure that it reviews its Credit Cover requirements.

To learn more about the purpose of the Credit Cover calculation, see our separate Credit Cover Guidance.

5. How do I find out a BM Unit’s P/C Flag and P/C Status?

A Lead Party can view their BM Unit’s Registration status by using the Elexon Kinnect Customer Solution. In addition, our Registered BM Units spreadsheet on the Elexon Portal provides a list of every BM Unit registered under the BSC, and its registration data.

This includes each BM Unit’s:

BM Unit ID and BM Unit Name;
[Lead] Party ID and [Lead] Party Name;
BM Unit Type;
Exempt Export Flag;
Base Trading Unit Flag;
P/C Flag;
P/C Status;
GC;
DC;
FPN Flag; and
Credit Qualifying Status.

‘Null’ Flags will show as blank cells.

Lead Parties can also use the Central Registration Agent (CRA)-I014 Registration Report to check this registration data for their own BM Units.

Lead Parties should ensure that they know the registration data for their BM Units. Please note that:

the Elexon Portal spreadsheet only shows the current information;
the CRA-I014 only shows Lead Parties any future-dated changes which they have requested for their own BM Units; and
neither will show any change in a BM Unit’s P/C Status which is caused by other BM Units (or the change in other BM Units’ GC/DC values or Trading Unit registration which triggered that P/C Status change) until after the event.

Need more information?

See:

You can find definitions of all capitalised terms in BSC Section X, Annex X-1: General Glossary.

Or contact Elexon Support.

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 Where the person generating electricity is either exempt from holding a Generation Licence, or would be if that was their only Generating Plant.

2 This includes Power Station demand units as well as Generating Units.

3 We no longer use this for new BM Units.

4 For a Supplier BM Unit, this is the relevant Supplier. For an Interconnector BM Unit, it’s the relevant Interconnector User. For a ‘generation’ BM Unit, it’s usually the person generating the electricity at the relevant Generating Plant. However, for an Exemptable Generating Plant, that person can authorise another BSC Party to accept the responsibility.

5A BM Unit that is not in a Trading Unit with other BM Units is in a sole Trading Unit.

6 For Primary BM Units, GC and DC are the Lead Party’s estimates of the BM Unit’s maximum expected Settlement Period generation or demand. For Trading Secondary BM Units, GC and DC are the VTPs estimates of the BM Unit’s maximum expected positive Settlement Period Deviation Volume and Maximum negative Settlement Period Deviation Volume. Lead Parties submit these under BSCP15 for each BSC Season, and must resubmit them during a season if the BM Unit’s expected maximum generation/demand exceeds the declared GC/DC value by more than the amount specified in BSC Section K3.4.

7 As well as potentially changing for each BSC Season, Lead Parties may re-declare GC/DC values at any time during a Season.

8 Contract Trading Parties are Parties that hold Energy Accounts or the NETSO. This includes Virtual Trading Parties but does not include Virtual Lead Parties.

CONTENTS

Production/Consumption Status and Flag V11.0

1. What is a P/C Status?

2. What is the P/C Flag?

3. How do we determine a BM Unit’s P/C Flat setting and P/C Status?

4. Why does P/C Status matter?

5. How do I find out a BM Unit’s P/C Flag and P/C Status?

Need more information?