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  • Interruptions to supply

  • National Transmission System Consumers 

    There are no longer any interruptible sites connected to the National Transmission System (NTS), the high pressure gas transportation system which provides supplies to the Distribution Networks and a number of very large industrial consumers.  From October 2012 new industry arrangements deem all sites as firm.

    Distribution Network Consumers

    A small number of interruptible sites may remain in the Distribution Networks, the gas distribution systems which provide supplies to domestic and most industrial consumers, as part of commercially contracted interruption.  It is also possible that industrial consumers could be interrupted by their suppliers depending upon the commercial arrangements they have agreed to.

    Capacity Products

    Industrial consumers may choose to make use of firm or off peak capacity products.  For further information on how these products may be impacted by localised system constraints please refer to the NTS Exit Zones and Exit Capacity Constraint Actions page.

    Gas Emergencies

    The Network Emergency Co-ordinator (NEC) is appointed to be an independent body whose responsibility in a major gas supply emergency affecting the NTS is to co-ordinate actions across the affected parts of the network to minimise the safety consequences of the emergency.

    Firm load shedding is the procedure used by transporters to secure a graduated and controlled reduction in demand on all or part of their systems in order to keep the system safely pressurised.

    During an emergency, industrial consumers using firm capacity may be contacted by their transporter and requested to stop using gas.  Consumers using the off peak capacity product can expect their off peak capacity entitlement to be scaled back prior to the declaration of the emergency.

    An emergency may be caused by unforeseen circumstances such as pipeline or equipment failure, or where system demand exceeds either total supply or planned system capacity.

    Your Obligations

    Minimising the safety impacts of emergencies requires the co-operation of everyone. All industrial consumers must be able to stop using gas following a direction notice from their transporter, safely and as quickly as practical. It is a criminal offence to knowingly fail to comply with a direction notice.

    Priority Consumers

    The Government has defined a number of categories for priority industrial consumers. Gas supply to these consumers will be maintained until operating conditions require the site to stop using gas to protect gas supplies to domestic consumers.  There are currently three categories of priority industrial consumer which are as follows:

    Category A
    Consumers (using more than 25,000 therms per annum, 732 megawatt hours) on firm supply contracts, where a failure in the supply to their premises could put lives at risk.  Examples of such consumers would be hospitals or homes for the elderly and disabled.

    Category B
    Distribution Network consumers who would otherwise fall into category "A" but are deemed as interruptible supplies.

    Category C
    Consumers operating major items of capital plant, which require time to be safely shut down and would sustain serious damage (£50 million or more) if gas supplies ceased suddenly. Examples of such consumers would be furnaces and glass works.

    If you feel your industrial premises should be classified as a priority consumer please contact your gas supplier in the first instance.

    • Contact us
    • For further information contact:

      Emergency Planning Team
      Gas System Operation
      National Grid
      National Grid House
      Warwick Technology Park
      CV34 6DA


      Or email