The Morlais Project aims to ensure mariners can continue to navigate safely in what is already recognised as a challenging navigational area. We also recognise the importance of Holyhead as an all-weather port and the need to ensure mariners can navigate safely to and from it. To this end we have carried out a comprehensive consultation with those with an interest in navigating in this area.

We have listened carefully to the navigational concerns raised by mariners and acted to assess and deal with these including a thorough and wide-ranging Navigational Risk Assessment (NRA) in accordance with the guidance laid down by the regulatory bodies. This process will continue as the project moves forward.

We have also worked hard to assess and mitigate any change to navigational risks as a result of the project. These details are included in the NRA which was carried out by marine experts.

We are aware that recreational/leisure mariners including sailors, motor boaters and kayakers make use of the inshore area close to the coast, particularly in the summer months and therefore we have paid special attention to ensuring they can continue to safely enjoy this area after the introduction of the Morlais Demonstration Zone.

It’s important to note that Morlais is a phased project and will take a number of years to implement.




Did you know that?

  1. The current expectation is that in the first 10-15 years, the deployment of tidal devices will cover less than 20% of the whole 35km2 zone area.
  2. We are not seeking to exclude mariners from the Morlais area. In the interests of safety there will be limited restrictions on Navigation during construction and future maintenance activities.
  3. We have reduced the area containing surface or floating devices by 60% as a result of consultation.
  4. The deployment of the tidal devices will be phased over a number of years and each phase will only be implemented after a full re-assessment of navigational risks and will take into account the navigational learning and feedback from the previous phase.
  5. The minimum width of the inshore passage is 1 kilometre (and is generally much wider than this). This is equivalent to over 30 ferries side by side! (Not that we’d ever expect to see ferries in this area!)
  6. 60% of the zone has an under keel clearance (UKC) of at least 8 metres at the lowest tide.



Extract from Imray Sailing Directions for Anglesey C52 Admiralty 1413 – Anglesey – Holyhead Bay

Guidance for this particular area:

“South Stack offers an area of particularly confused sea and in heavy conditions an offing of 7 miles is needed to avoid overfalls and tide races.”

Further, they say “In the event that there is any sign of a tide race off either Stack it may be advantageous to stand in close to the cliffs and cut through the race as near as possible to the rocks. It may be dangerous to attempt passage round the Stacks, in either direction, in any sort of wind over tide conditions or with winds of Force 5 or greater.”



For project background and timelines, please refer to the home page

For examples of different tidal stream energy devices please click here


Important: Images and information on this site should not be used for Navigation.



Example of expected deployment during Phase 1 (~12MW) showing operational exclusion zones



Example of expected total deployment during Phase 2/3 (~100MW) showing operational exclusion zones



Example of expected total full deployment (~240MW) showing operational exclusion zones



Example layout of devices to make best use of tidal flow speeds

(sub-surface devices in the 8m and 20m UKC areas are not shown)



Coloured areas showing restrictions on the types of turbine permitted and showing operational exclusion zones