What are MNs and GBNs? 

A Margins Notice is a message sent to all shippers indicating a potential supply/demand imbalance for the next gas day. Its aim is to encourage shippers to consult the rolling Daily Margins Report and reassess their imbalance position. 

Margins Notices are issued from 1pm on the day before the gas day in question (D-1). We issue these notices when necessary after we have assessed the expected available level of gas supply against forecast total demand. If demand is greater than supply (by any value), we issue a Margins Notice.  

A Margins Notice cannot be withdrawn and remains in place until the end of the gas day to which it applies – unless it is superseded by a Gas Balancing Notification. 

Find out more about Margins Notices: Operational Guidance Material - Margins Notice  

The aim of a Gas Balancing Notification is to stimulate a rapid market response to address an expected physical imbalance on the network. We issue a GBN before or during a gas day if we believe there is a material risk to the physical end-of-day balance. These events require shippers to take prompt action. 

If a GBN is issued, the On-the-day Commodity Market (OCM) will remain open. We may also consider over-the-counter trades and multi-day trades.

A GBN withdrawal notice is issued, at our discretion, if circumstances are resolved and there is no longer a risk to the end-of-day physical gas balance.

Find out more about Gas Balancing Notifications: Operational Guidance material – Gas Balancing Notification

How are notifications issued?

We issue all gas balancing information on our website, through the Data Portal under the 'Gas System Status' header.

When a GBN is issued, we send Active Notification System (ANS) messages to authorised users registered with the service. The messages are also posted in the ANS message area of the Data Portal.

Daily Margins Notice and Safety Monitor reports

Our Margins Notice Forecast and Safety Monitor position update report (updated every day from 1 October to 31 March) provide data on supply and demand assumptions, and a daily declaration of the D-1 margins notice trigger level. The report is updated daily following the D-1 1pm NTS demand forecast.

Over-the-counter and multi-day trades 

As operator of the NTS, we can facilitate over-the-counter (OTC) and multi-day trading if a GBN is issued. In line with the Uniform Network Code (UNC), we may seek to enter into non-system transactions with users (as defined in the UNC). We will only enter into non-system transactions: 

• when a GBN has been declared for the relevant gas day; 
• with gas shippers who are a party to the UNC and are not an OCM subscriber; 
• up to a maximum duration of seven days from the time the offer is made (i.e. offers made day-ahead can only have a six-day duration); and 
• after consideration of the system balance and the offers available via the OCM and OTC. 

This may mean that actions are not taken immediately following an offer being made. If offers are time-constrained, this should be made clear at the time the offer is made using the 'OTC Offer to sell under an NBP Trade (P160)'. 

Payments for any accepted OTC offers will be as per the original price and invoiced through an ad-hoc energy balancing invoice (EBI). 

A summary of the process for making and accepting offers in relation to OTC/OCM multi-day trades is available in the OTC Flowchart document.  A more detailed shipper procedure is available in the ‘Shipper Procedure for Over the Counter Trading’ document. 

Multi-day trade offers may also be made using the OCM by subscribers using the locational market. These may be made up to a maximum duration of seven days from the time the offer is made. The process for single day OCM offers is unaffected by a Gas Balancing Notification. 

You can find information about system prices in the ‘Impacts on SAP, SMPB and SMPS of OTC or OCM Multi-day Trades’ document. Multi-day trade weighting factors will be published here if a Gas Balancing Notification is declared.  Here is an example.