Until now the UK has been self-sufficient in gas, thanks largely to abundant supplies from gas fields, predominantly in the North Sea. Unfortunately this situation will not continue. At the moment, the UK has more than 21 million gas customers and this number is rising daily. The reality is that the offshore fields are decreasing in output and demand for gas from homes and businesses is growing at such a rate, that analysis shows that the UK will become increasingly dependent upon imported gas over the coming years.

Two new terminals to import Liquefied Natural Gas (LNG) have bee developed on the outskirts of Milford Haven by South Hook LNG and Dragon LNG. The LNG will arrive by ocean-going tanker.  On arrival at the terminals it will be transferred ashore into LNG storage tanks and then converted back into natural gas for onward transportation through National Grid's gas transmission system.

 Although the terminal developers are independent from National Grid, under the terms of our operating licence we had a duty to connect them to our gas transmission network, to ensure that the gas they export is safely and economically delivered to where it is most needed by users throughout the UK.

To connect the new terminals, and to reinforce the existing national gas transmission System, we have built two new pipelines. The pipelines, which are 1220mm in diameter and 316km in length, carry exactly the same type of natural gas as used in the home and run underground from Milford Haven to Aberdulais, near Neath, and from Felindre, near Swansea to Tirley in Gloucestershire. Pipeline construction is complete, although a small amount of reinstatement of the land will continue in 2009.  This does not affect their operation in any way.

Above ground installations

In addition to the pipelines, a number of above ground installations are required.  Construction work has been completed on all except one of these.   Final commissioning is due to be carried out once the gas begins to flow from the terminals at Milford Haven.

To enable the pipelines to operate at full capacity, we need to build a new pressure reduction installation (PRI) near to Tirley, in Gloucestershire.  In December 2008 we submitted a planning application to Tewkesbury Borough Council for permission to build a new PRI on land to the east of Flat Farm in Tirley.  Subject to planning permission being granted, construction will take approximately 15 months.

More information

Further information on the Tirley PRI is available in Fact Sheet 7.  If you would like to contact us, please call the project information line on 0800 731 0561 or email: enquiries@milfordhavepp.co.uk

• Large map (Opens in new window)