Network Development Statement 2010/11 to 2019/20 - Gaslink

5. The ROI Transmission System
5.1 Overview of the existing ROI gas network
The ROI gas network consists of approximately
12,923kms of high-pressure steel transmission pipeline
and lower pressure polyethylene distribution pipelines,
Above Ground Installations (AGIs), District Regulating
Installations (DRIs) and compressor stations in the ROI
and Scotland. The integrated supply system is sub-divided
into 2,147kms of high pressure sub-sea & cross country
transmission pipes and approximately 10,776kms of lower
pressure distribution pipes. The distribution network
operates in two tiers; a medium pressure and a low
pressure network. The high-level system statistics are
summarised in Tables 5.1 and 5.2 and shown in Figure 5.1.
The ROI transmission system includes the IC system and
the onshore ROI system. The IC system includes two
subsea Interconnectors to Scotland; two compressor
stations at Beattock and Brighouse Bay, and the 110-km
of onshore pipeline between Brighouse and Moffat in
Scotland.
The IC system connects the onshore ROI system to the
GB National Transmission System (NTS) at Moffat in
Scotland. It also supplies gas to the NI market from
Twynholm and to the IOM market from IC2. The IC
system is also used to provide a gas inventory service
to ROI shippers (see Fig. 5.1)
The onshore ROI system consists of a ring-main
system between Dublin, Galway and Limerick, with
cross-country pipelines running from the ring-main
system to Cork, Limerick, Waterford, Dundalk and the
Corrib Bellanaboy terminal in Mayo. It also includes a
compressor station at Midleton.
Table 5.1: ROI Pipeline summary statistics
Location Current Max
MOP* Total Nominal Pipe
Pressure Length Diameter
(bar-g) (km) (mm)
Onshore ROI 85.0 160.9 650
Onshore ROI 1 75.0 60.1 450
Onshore ROI 70.0 1,132.9 900
Onshore ROI 40.0 91.6 500
Onshore ROI 2 37.5 14.6 600
Onshore ROI 3 19.0 152.0 600
Onshore ROI 7.0/4.0 15.8 600
Subtotal N/A 1,627.9 N/A
Scotland 85.0 109.9 900
Subsea 148.0 409.0 750
Total Tx N/A 2,146.8 N/A
Onshore Ireland Dx >100mBar 6,395.4 315
Onshore Ireland Dx