Under normal operating conditions supplies of gas entering the National Transmission System (NTS) are matched to the demand for gas leaving the system and pressures within the system remain within an acceptable range.
As operator of the NTS, we are responsible for ensuring that a supply – demand balance on the NTS is achieved. We have a range of system balancing tools to match supply and demand.
A network gas supply emergency (NGSE) occurs when we are unable to maintain a supply – demand balance on the NTS using our normal system balancing tools. As a consequence of the imbalance between supply and demand, pressures in the system fall and it may not be possible to safely maintain gas supplies to industrial and domestic gas consumers who are supplied with gas either directly or indirectly from the NTS.
A NGSE could be caused by a major loss of supplies to the system as a result of the failure of a gas terminal or as the result of damage to an NTS pipeline affecting the ability of the system to transport gas to consumers.
If we were unable to maintain a supply – demand balance on the NTS using our normal system balancing tools, we would request the network emergency coordinator (NEC) to declare a NGSE.
The declaration of a NGSE would provide us with access to additional balancing tools for use in restoring a supply – demand balance. These emergency tools include requesting additional gas supplies be delivered to the NTS, or requiring gas consumers, starting with the largest industrial consumers, to stop using gas. These tools will be used, under the authorisation of the NEC, to try to maintain supplies to domestic gas consumers as long as possible.
The cooperation of gas industry participants, including gas terminal operators, gas shipping companies, gas transportation companies and large industrial consumers, is required to successfully implement the emergency system balancing actions. Sufficient emergency balancing actions will be undertaken to restore a supply-demand balance on the NTS and minimise the safety consequences of the emergency to gas consumers.
Once a supply – demand balance has been achieved and the safe operation of the system ensured, supplies will be restored to consumers a soon as practicable. Once supplies have been restored to all consumers who are supplied with gas directly from the NTS, the end of the NGSE will be declared by the NEC.
You can find a more detailed breakdown of the process in the Procedure for Network Gas Supply Emergency (T/PM/E/1) document.
There has, to date, never been a network gas supply emergency.
