National Grid is planning a 22km-long, five-metre diameter tunnel to link the proposed Moorside nuclear power station to the National Grid network.
Morgan Sindall Professional Services (MSPS) and its sister business Underground Professional Services (UnPS) are near to completing the front end engineering design (FEED) for what is considered to be one of the most technically challenging projects of its type ever proposed.
Awarded the contract in September 2015, and having now completed a significant portion of the reference design, the design team has supported National Grid through a public consultation, which closed on 6th January 2017. The next steps are an application for a development consent order (DCO) prior to issuing an invitation to tender.
The £2.8bn tunnel is part of the North West Coast Connection (NWCC), a plan to connect and export electricity generated by Moorside – a proposed 3.4 GW nuclear power station near Sellafield in west Cumbria. To minimise impact on the Lake District, the power will be transmitted via a cable tunnel below Morecambe Bay’s seabed, between Barrow in Furness and Heysham. The cable tunnel will enable the National Grid network to be fed from the power station’s energy source.
The proposed tunnel will house two 400kV cable circuits. Due to the ventilation requirements, and to ensure the high voltage (HV) cables do not overheat when fully loaded, an islet in the middle of the bay is proposed as a heat ventilation point and an emergency escape.
National Grid senior project manager Neil Lyons said: “This project requires various bespoke tunnel construction methodologies and linings designs, an understanding of marine works, and all the associated challenges from both HV cable installation and operational point of view, all with safety being at the forefront.
“The team has supported us from the outset, adapting designs with multiple options to satisfy different stakeholder groups, and completing the reference design within a very tight timeframe. We now look forward to their continuing support in our application for a DCO and in the subsequent invitations to tender.”
MSPS and UnPS are now finalising all aspects of the tunnel and shaft design, islet, and head house development together with its associated mechanical, electrical, civil and structural infrastructure works. In addition, the HV cable system and installation proposals will be developed with National Grid.
Further specialist services including marine and environmental engineering, planning, architectural design, third party engagement and transportation management are also being provided as part of the scope.