Follow us on:

Twitter YouTube
Facebook Like us

Contact us

Contact us

Email updates?

Email updates?


Send to

Send to friends





Text size:

Text Size - Small Text Size - Normal Text Size - Large

Tunnelling at the Menai Strait

We are proposing a tunnel to go under the Menai Strait. Coming to this decision and establishing how we will overcome the technical challenges of crossing the Strait has taken a lot of work.

We’ve looked at the setting of communities, the landscape and important features such as Bryn Celli Ddu, Plas Newydd and the Vaynol Estate. We have also considered the wildlife and marine environment and the feedback we have had about the area. 

We have needed to consider a number of practical issues such as the geology, how deep we would have to go, and the space we would need for drilling or tunnelling equipment. 

We’ve also had to think about the effects of any above ground infrastructure. This included routeing an overhead line to the area, the sites for sealing end compounds which we need to change from overhead to underground and tunnel head houses. Temporary construction areas and traffic access were further important considerations.

 Cost was a further consideration as any money we spend is passed on to all of us through our electricity bills. 

All this has influenced the technology we will use to make the crossing, the location of equipment and where is most suitable to actually cross.

(Click image to enlarge)

Tunnelling at the Menai Strait

Finding the balance

We’ve worked hard to solve these challenges and find a solution that best balances all of these considerations. We: 

  • worked with the SEACAMS team at Bangor University and others to survey the seabed and take rock samples to confirm the nature of rock in the area 
  • looked at feedback from local people about what they considered was important so we could take this into account 
  • assessed different crossing points to find a good location to go under the Strait based on the geology and other environmental factors 
  • identified sites that had enough space for the equipment we require permanently and during construction 
  • considered these sites based on the landscape and their potential for natural screening either with existing trees and woodland or through new planting 
  • also considered the effects of a new overhead line to connect to the sites 

We decided that a tunnel was the best technology option. It provides the best option to avoid impacts on marine wildlife and also has less disruption on the land than laying cables in trenches, which would have needed to have run up close to the banks of the Menai Strait.

You can see how the proposals might look in your area by exploring our interactive map.

Marine licence application

We need to carry out some investigation works at the Menai Strait to understand more about the geology and ground conditions beneath it. We’ve submitted an application to Natural Resources Wales for a marine licence to allow us to carry out this work.

The following documents include a copy of our application and the documents that support it:


Register   >

You can register to keep up to date with the project