Types of Interruptible Site

There are two classifications of Interruptible Site. These sites form part of Transco's strategy for the safe and secure operation of the network under different circumstances.

Detailed below are the different classifications of Interruptible Sites:-

Shipper Nominated Interruptible

Sites which are classified as 'Shipper Nominated Interruptible' (SNI) receive a reduction in the transportation charge which may be included in the price of gas. In return Transco can interrupt these supply points for up to 45 days in each Gas Year. SNI is a non-Network Code term and care must be taken in not confusing Transco interruption at an SNI with a commercial interruption carried out by shippers, sometime referred to as "shipper interruption".

Transco Nominated Interruptible

Transco can designate a site Transco Nominated Interruptible (TNI) by giving at least 12 months notice. This gives Transco the ability to interrupt these sites for more than the usual 45 days (for example, up to 60 days in a 1-in-50 cold winter). This number of interruptible days is determined by Network Planning and is a specified number for each site.

In addition sites which are located in a particularly vulnerable part of the network are described as Network Sensitive Loads. These can be either TNI or SNI.

Network Sensitive Loads

Sites which are designated as Network Sensitive Loads (NSL) are those which are on a part of the network that has limited transportation capacity. These sites are required to interrupt in order to maintain supply pressures to firm end users, at a level which avoids an actual or potential supply emergency, as defined by the Gas Safety (Management) Regulations 1996. As a result, a NSL may have a higher probability of being interrupted, particularly during mild weather conditions, than other sites.

Note: For further information regarding pricing please refer to the current pricing document