System Operations
Emergency planning
In the unlikely event that one occurs, National Gas has robust procedures in place to deal with a Network Gas Supply Emergency (NGSE). The Network Emergency Co-ordinator (NEC) coordinates actions across the gas networks to prevent a supply emergency developing.
A supply emergency could be caused by a pipeline or equipment failure, or when system demand exceeds total supply or planned system capacity. Our emergency arrangements are regularly tested in industry-wide exercises to ensure they remain effective and up to date.
Take a look at our introductory video explaining how our emergency processes work.
What is a Network Gas Supply Emergency (NGSE)?
Under normal operating conditions, supplies of gas entering the National Transmission System (NTS) are matched to the demand for gas leaving the system – keeping pressures in the system within an acceptable range. As Gas System Operator (GSO), we have a range of tools at our disposal to help keep supply and demand in balance on the NTS.
A Network Gas Supply Emergency (NGSE) occurs when we are unable to maintain this balance using our normal system balancing tools – perhaps due to a major loss of gas in the system following a gas terminal failure or damage to a pipeline. A loss of supply into the NTS causes pressure in the network to drop, meaning we may not be able to safely deliver gas to consumers.
In these extreme conditions, and in the event that our normal balancing tools are inadequate to remediate the situation, we would ask the Network Emergency Co-ordinator (NEC) to declare a NGSE. A “supply emergency” is defined as “an emergency endangering persons and arising from a loss of pressure in a network or any part of that network.”
Declaring a NGSE gives the GSO access to additional tools to restore the supply-demand balance. These emergency tools include requesting additional gas supplies into the NTS, or requiring gas consumers to stop using gas, starting with the largest industrial consumers.
The cooperation of gas industry participants, including gas terminal operators, gas shipping companies, gas transportation companies and large industrial consumers, is essential for these emergency balancing actions to be effective. Sufficient emergency balancing actions will be used to restore a supply-demand balance on the NTS and minimise the safety consequences for gas consumers.
Once a supply-demand balance has been achieved and supplies have been restored to all consumers directly connected to the NTS, the NEC will declare the end of the NGSE.
There has, to date, never been a Network Gas Supply Emergency in Britain. But we remain ready and have full operational and commercial capabilities to deal with one.
What is the Network Emergency Co-ordinator (NEC)?
The Network Emergency Co-ordinator (NEC) is an independent body that sits outside of all energy companies. It is independent from any commercial interests of gas industry participants. The NEC has responsibility for declaring a Network Gas Supply Emergency (NGSE) if National Gas alerts it to an actual or potential loss of pressure, in any part of the gas network, which cannot be solved via commercial means.
In this circumstance, the NEC has complete authority to direct flows of gas on and off the gas network, to protect those who would be in greatest danger if they lost their gas supply. Industry participants, such as gas transportation and gas shipping companies, have a legal duty to cooperate with the NEC. Failure to comply with the NEC’s directions is a criminal offence. It requires an order in privy council for any wider stakeholder to direct the NEC to take action outside the obligations set out by the HSE in its Safety Case.
The NEC can take various actions during an NGSE to restore a supply/demand balance, such as:
- widening gas quality limits to maximise the supply of gas;
- implementing a load-shedding protocol to run down industrial demand;
- making public appeals to reduce the use domestic of gas; or
- managing domestic supply as a last resort.
These actions are impactful. They are only undertaken if the market has failed, and they are vital to prevent the health and safety implications of a loss of pressure on the gas network. Once gas supplies have been restored to the network, the NEC would declare the emergency over and normal operation would resume.
The NEC has established support arrangements to help it discharge its legal duties. The National Gas Energy Emergency team supports the NEC by organising periodic industry-wide emergency exercises to assess the effectiveness of the response to a gas supply emergency.
NGSE procedures: understand what happens in a gas supply emergency
Detailed information about the processes followed in the event of a NGSE can be found in E1 NGSE Procedure. This document also describes the types of NGSE that could be declared, the emergency actions that may be authorised, and the four stages of an emergency as defined by the NEC.
Industry exercise participant requirements
The following documents provide more information about the participation requirements for NEC industry exercises.
Directly Connected Sites
Shippers
Storage Operators
Supplementary Transporters
Terminals
Exercise Reporting
Emergency proformas
NEC Declaration or industry update form & NEC Declaration of end of NGSE form
Distribution networks and interconnector forms
Storage injection notification forms
Supply forms
Shipper forms
Market actions (ICE ENDEX forms)
NEC Declaration or industry update form
This proforma provides the NEC declaration of the NGSE or an update of the emergency
stage.
NEC Declaration of end of NGSE form
This proforma is issued to the industry to declare the end of a NGSE
Please contact the Energy Emergency team to discuss any of the following:
Distribution network forms
- NETMAN1 and Minimal Critical Offtake Pressure Form
- Distribution Network Demand Reduction Form
- Distribution Network Additional Gas Requirements Form
- Distribution Network Situation Report Form
- GS(M)R Schedule 3 Part 2 Gas - Information Form
- GS(M)R Schedule 3 Part 2 Gas - Authorisation Form
- GS(M)R Schedule 3 Part 2 Gas - Withdrawal Form
- GS(M)R Schedule 3 Part 2 Gas – Revocation Form
Interconnector forms
- GNI Demand Breakdown Request Form
- GNI Demand Reduction Notification Form
- GNI Notice of Revocation Form
- Interconnector Demand Reduction Notification Form
- Interconnector Notice of Revocation Form
Storage information request form
A request for storage information sent to storage operators to determine the available supply
to meet demand.
Storage injection notification form
A direction to affected storage operators to amend their storage injection flows due to a
breach in the Safety Monitor.
Storage withdrawal curtailment notification form
A direction to affected storage operators to curtail or amend their storage withdrawal flows due to a breach in the Safety Monitor.
NTSA Gas Availability Status (GAS) Report
A gas availability status report from the UK offshore supply sector over the next 48 hours.
Terminal/LNG flow direction notification form
A direction for amended supply into the NTS for use in emergency stage 2/3/4 of a gas
deficit emergency to terminal/LNG operators.
GS(M)R direction notice to NTS directly connected sites
To inform shippers that GS(M)R direction notices have been issued to NTS directly
connected sites to reduce/stop using gas.
GS(M)R revocation notice to NTS directly connected sites
To inform shippers that GS(M)R direction notices have been issued to NTS directly
connected sites to resume using gas.
ENDEX suspend National Gas market actions proforma
A proforma to the On-the-day Commodity Market (OCM) facilitator to suspend National Gas
participation in the OCM at stage 2 of a gas deficit emergency.
ENDEX reinstate National Gas market actions proforma
A proforma to the On-the-day Commodity Market (OCM) facilitator to reinstate National Gas
participation in the OCM at the end of a gas deficit emergency.
EMERGENCY CURTAILMENT QUANTITY (ECQ)
ECQ process
Post-event information provision
Shipper curtailment
P70 forms
The emergency curtailment quantity (ECQ) process relates only to sites (system exit points) curtailed as part of a gas deficit emergency. The ECQ process assigns the quantities of gas associated with emergency curtailment actions undertaken by transporters as a trade nomination between National Gas Transmission, as residual system balancer, and each user.
The objective of the ECQ process is to ensure that shippers’ imbalance positions for the day are unchanged if transporters curtail the offtake of gas at sites as part of a gas deficit emergency.
For every affected user, the ECQ value is calculated as the aggregate quantity of emergency curtailment which has occurred, less any quantity of user commercial interruption at the relevant sites.
Details of how ECQ is calculated can be found in the ECQ Methodology on the Joint Office
website.
In accordance with UNC, National Gas Transmission will notify shippers of the ECQ for each day of curtailment and the proportion of that ECQ which relates to each transporter.
A summary of the process – including communications – can be viewed on this high-level overview process flow document: Emergency Curtailment High Level Overview document. The NTS report is referred to as the 'transporter ECQ report' on the ECQ high-level overview document. Where NTS system exit points have been curtailed, National Gas Transmission will endeavour to provide relevant users with a site-specific report detailing the method used to calculate the ECQ. This is referred to as the NTS ECQ report on the ECQ high-level overview.
If a user chooses to interrupt a site, the relevant transporter should be notified via a P70
form. Sites that are subject to a P70 will be excluded from ECQ calculations.
For more information: Download the P70 FAQs guidance document
NTS P70 (Curtailment) document – notify National Gas Transmission of shipper
curtailment at directly connected NTS sites.
NTS P71 (Restoration) document – notify National Gas Transmission of shipper
restoration at directly connected NTS sites.
DNO P70 (Curtailment) document – notify distribution network owner (DNO) of shipper
curtailment at directly connected NTS sites.
P71 (Restoration) document – notify distribution network operator (DNO) of shipper
restoration at directly connected NTS sites.
STORAGE CURTAILMENT COMPENSATION
STORAGE CURTAILMENT COMPENSATION
The storage curtailment compensation arrangements enable users (who tend to be gas shippers) to be financially neutral if a storage curtailment is undertaken by the Network Emergency Coordinator (NEC). A storage curtailment occurs where there is a reduction or cessation of delivery of gas to the NTS from a storage facility, following either a direct or indirect request by the NEC.
You can find details relating to storage curtailment in the Uniform Network Code (UNC) Transportation Principal Document under Section Q.
SCP and SCCQ shipper procedure document
SCP and SCCQ statement spreadsheet
POST-EMERGENCY CLAIMS (PEC)
POST-EMERGENCY CLAIMS (PEC)
Supporting information – OCM process
PEC reports
Post-emergency claims (PEC) can be made for additional gas offered to the UK gas system
during a gas deficit emergency (GDE). The post-emergency claims rules are detailed in UNC
Q4.5.
Post-emergency claims (PEC) user guidelines – the processes and procedures for
claimants seeking to submit an eligible PEC:
Post-emergency claims economic assessment guidelines – guidelines for economic
price assessment of post-emergency claims.
Post-emergency claims (PEC) form – claims should be submitted via email
to [email protected] within six days of the GDE to which the
claim relates, using this template.
As the OCM physical market is used to submit offers, please find below details of the physical renomination process for accepted offers and examples:
Renomination example for turndown document – an example of how renominations would work if physical offers for turndown on the OCM were accepted.
Physical renominations example for turnup document – an example of how renominations would work for a turnup if physical offers on the OCM were accepted.
OCM physical renominations on Gemini presentation – presentation for users of Gemini.
Following receipt of PECs, we will use reasonable endeavours to publish information relating to claims here as detailed in the UNC. Example templates for the reports are attached below for information. If required, PEC reports will be published here.