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 been developed on the outskirts of Milford Haven by South Hook LNG and Dragon LNG. The LNG arrives by ocean-going tanker and is transferred ashore into LNG storage tanks, 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 provide is safely and economically delivered to where it is most needed by users throughout the UK.

The pipelines
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.
 
Above ground installations
Construction work has been completed on all except one of the above ground installations also required. 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. In February 2010 Tewkesbury Borough Council’s planning committee refused the planning application, despite it being recommended for approval by the Council’s planning officer. We appealed against the decision by the Council and, as a result of a Local Public Inquiry which took place in July 2010, our appeal has been upheld and we now have planning permission to build the PRI.
 
More information
Further information on the Tirley PRI is available in the Fact Sheet on this website (see left hand column). If you would like to contact us, please call the project information line on 0800 731 0561 or email: enquiries@milfordhavenpp.co.uk.

http://www.nationalgrid.com/uk/Gas/Pipelines/milfordhaven/corsepri/

Tirley pressure reduction installation
 
Why is a new pressure reduction installation needed?

Pressure reduction installations (PRIs) help to control and regulate the flow of gas and need to be located at strategic points to ensure the country’s gas network operates efficiently and economically.

National Grid first applied for planning permission to build a new PRI on a site at Corse, immediately west of the existing Tirley above ground installation (AGI), in April 2006. The application was refused by Forest of Dean District Council.

The Council’s decision was upheld following an appeal in 2007, but the Secretaries of State clearly acknowledged the national importance and urgency for the construction of a PRI in the vicinity of the existing Tirley AGI.
 
Site selection process
Following this decision, we carried out an extensive evaluation of potential sites for the PRI within a 10km radius of Tirley AGI. We concluded that our preferred location is on land to the east of Flat Farm, off the B4213 just to the east of Tirley AGI. Using this site would also allow us to remove our above-ground equipment from Tirley AGI and return that site to a greenfield site.

In December 2008 we applied to Tewkesbury Borough Council for planning permission to build the PRI on the land to the east of Flat Farm. Whilst the application was being considered, we listened closely to the feedback the Borough Council was receiving and modified our proposals to address the points raised by local residents and consultees.
This resulted in the application being recommended for approval by the Council’s planning officer, but the Council’s planning committee members went against that recommendation and refused planning permission in February 2010.
 
Our appeal
Having carefully considered the reasons for refusal, and in view of the national importance of the PRI, we submitted an appeal to the Secretaries of State for Communities and Local Government and Energy and Climate Change on 25 February 2010. The appeal was heard at a Local Public Inquiry which took place at Corse and Staunton Village Hall in July 2010.

The Planning Inspector who heard the appeal submitted his report to the Secretaries of State for Communities and Local Government and Energy and Climate Change in early October 2010 and, based on the evidence presented, he recommended that National Grid’s appeal be upheld and permission to build the PRI be granted. In their report the Secretaries of State have agreed with the recommendation of the Planning Inspector and have granted National Grid planning permission to build the PRI on land to the east of Flat Farm, Tirley.

Since permission to build the PRI was granted in December 2010 we have been working closely with Tewkesbury Borough Council’s planning department to meet the planning conditions attached to the decision. In March 2011 we started construction and expect to commission the PRI to gas in late summer 2012. This will enable the South Wales gas pipeline to flow at its maximum operating pressure of 94 bar, supplying up to 20% of the UK’s gas requirement.
 

Construction
The methods used to construct the PRI are based on best industry practice, which includes plans to manage the effects of noise, dust and construction traffic on local communities and roads.

In the design of the new PRI we have been able to incorporate the functionality of the existing Tirley AGI. Upon completion of the new PRI, the existing AGI near the junction of the B4213 and B4211 will be completely removed and the area returned to a greenfield site.

Construction of the new PRI and reinstatement of the temporary working area will continue until the end of 2012.
 
Safety
Safety is a top priority for National Grid and we have an excellent safety record. Great Britain’s high-pressure national gas transmission system has been in operation for more than 40 years, and has never experienced a serious incident affecting life or property – the means by which safety performance is normally defined.

PRIs and their associated pipelines are designed, constructed and operated to the most exacting safety standards set out by the Institution of Gas Engineers and Managers and regulated by the Health and Safety Executive. Pressure vessels and pipes are constructed using high-grade steel, and undergo rigorous testing before commissioning.

Once constructed, the PRI is an extremely safe and secure installation, protected from interference by a series of fences and security systems.
 
Minimising our impact on the community
National Grid takes its responsibilities to local communities seriously. We are committed to working with local people to minimise the impact of our work wherever possible.

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