We are looking for feedback about our new website.

Margins Notices (MN) and Gas Deficit Warnings (GDW)

Margins Notices (MN) and Gas Deficit Warnings (GDW) provide relevant parties with information about potential or actual risks to the end-of-day National Transmission System (NTS) physical system balance. On this page you will find out more about MN and GDW, including what to do when there is a significant supply or demand event.

We issue these notices and warnings to provide information about risks to the end-of-day NTS physical system balance. National Grid NTS has three categories of gas balancing information:

  • MN;

  • GDW issue; and

  • GDW withdrawal.

The notices and warnings replaced the prevailing gas balancing alert (GBA) arrangements in December 2012 following approval of UNC modification 0415.

We issue all gas balancing information site on our website, through the Prevailing View page under the 'System Status' header.

If a GDW is issued or withdrawn, ANS messages will be distributed to authorised users registered with the service. The message will also be available within the ANS message area of the Prevailing View page.

We also offer a text and email notification service to provide updates on the GDW. Please provide your details via the link on the registration page for the free subscription service or login to manage your subscriptions.

Margins Notices (MN)

An MN is information provided to all NTS users, indicating a potential supply/demand imbalance for the coming gas day. An MN is issued from 13:00 D-1, following an assessment of the expected available supply level against forecast total system demand. If demand is greater than supply (by any value), an MN will be issued via ANS.

MNs are intended to provide NTS users (shippers) with a high-level, day-ahead notice of a potential supply/demand imbalance for the coming gas day. The notices encourage NTS users to consider the rolling Daily Margins Notice Report (below) and reassess their position, relative to prevailing forecasts.

An MN cannot be withdrawn and will remain in place until the end of the gas day for which it is applicable, unless superseded by a gas deficit warning.

Gas Deficit Warnings (GDW)

A GDW is given at our discretion, based on our expectations of the impact of a significant supply/demand event. A GDW will be issued in advance of or during a gas day if a significant supply/demand event is experienced which instigates a material risk to the physical end-of-day balance.

Shippers should seek to balance their portfolio and be prepared to respond accordingly to any balancing action requests from us. If a GDW is issued, the On the Day Commodity Market (OCM) will remain open. In accordance with UNC, if a GDW is issued, we may consider over-the-counter trades. For further information, please read about over-the-counter and multi-day trades.

A GDW withdrawal notice will be issued at the discretion of National Grid NTS once the circumstances leading to its issue have been resolved and there is no longer an actual or imminent risk to the safety of the NTS end of day physical balance.

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 GDW 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 GDW has been declared for the relevant gas day;

  • with gas shippers who are a party to the Uniform Network Code 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) in EBI invoice timescales.

The terms applicable to any such non-system transactions shall be in accordance with the Short-Term Flat NBP Trading Terms and Conditions Ref. NBP 2015 (NBP 15), amended as follows:

  • Clause 6 of NBP 15 shall be deleted and replaced with the words: "The amount payable by National Grid to the Seller in respect of NBP Trades shall be invoiced as Market Balancing Action Charges under the Uniform Network Code and in particular Section S of the Transportation Principal Document."

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 also be made 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). The process for single day OCM offers is unaffected by a gas deficit warning.

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 deficit warning is declared.  Here is an example of the specimen.

Further enquiries

For more information about the OTC contract, please contact David Preston on 01926 65 4611.

In the event of a GDW, OTC offers should be submitted by fax using the 'OTC Offer to sell under a NBP Trade (P160)' document. The fax number for these submissions is 0870 191 0646. Please note that 0870 numbers will cost 7p per minute plus your phone company’s access charge. If you have any queries, please call 0870 191 0636.

All trade confirmations should be submitted using the proforma for 'Confirming an accepted OTC Offer (NBP15)' document. Once completed and signed, please send it (along with statements, invoices, and queries relating to settlement) to:

Settlement Team
Market Operation
National Grid
Gallows Hill
Warwick
CV34 6DA

Fax number: 01926 656613
Phone number: 01926 654960

Daily margins notice and safety monitor report

This section contains the daily margins notice and safety monitor position update report, along with supporting information regarding UK gas storage safety monitors.

This report provides data relating to supply and demand assumptions, and a daily declaration of the D-1 margins notice trigger level. The report will be updated daily following the D-1 13:00 NTS demand forecast.