Gas transmission deal with the large high pressure pipelines that convey gas to the distribution systems. There are four transmission pipelines in Northern Ireland:
- SNIP (Scotland to Northern Ireland Pipeline) is 135 kilometres long and runs from Twynholm in Scotland to Ballylumford in Northern Ireland. The SNIP is owned by Premier Transmission Limited which is part of the Mutual Energy Ltd. group of companies.
- BGTP (Belfast Gas Transmission pipeline) is 26 kilometres long and is connected to the SNIP and to the North West Pipeline. It also supplies gas to the Belfast distribution network. The BGTP is owned by Belfast Gas Transmission Limited (BGTL) which is part of the Mutual Energy Ltd. group of companies.
- NWP (North West Pipeline) is 112 kilometres long and runs from Carrickfergus to Coolkeeragh Power-station. It is owned by BGE Northern Ireland (BGE NI)
- SNP (South North Pipeline) is 156 kilometres long and runs from Co Antrim to Gormanstown in Co. Meath, Ireland where it links into the NWP. It is owned by BGE Northern Ireland (BGE NI).
Gas transmission also deals with the regulatory framework for gas storage which is discussed further below under the projects section.
Gas distribution deal with the medium and low pressure gas mains that convey gas to licenced areas within Northern Ireland. There are three distribution licensed areas within Northern Ireland:
Greater Belfast and Larne distribution licensed area - operated by Phoenix Natural Gas Limited (PNGL)
Ten Towns distribution licensed area - operated by firmus energy (Distribution) Limited (feDL)
West distribution licensed area - operated by Evolve (previously SGN NG)