OES-Environmental distributes metadata forms (questionnaires) to solicit information from developers involved in environmental monitoring around marine renewable energy project sites around the world. This page provides project descriptions, baseline assessment, post-installation monitoring, and links to available data and reports. Content is updated on an annual basis.

Morlais Tidal Demonstration Zone

Description

Morlais is a Menter Môn grid-connected, tidal stream array demonstration project located to the west of Anglesey, Wales. The goal of this project is to benefit local communities, the economy and help tackle climate change by using renewable energy to generate clean low carbon electricity. 

Location

The Morlais project consists of a 35 km2 area of seabed off the coast of Holy Island, Anglesey in Wales.

The Project is located within one of several marine energy demonstration zones located around the United Kingdom (UK) coast, which were leased out for 45 years by The Crown Estate (TCE) in 2014 in a bid to encourage and accelerate the marine energy industry. The Project is located within the West Anglesey Demonstration Zone (WADZ), a zone primarily selected for its tidal stream resource.

Licensing Information

Menter Môn applied to Welsh Government under the Transport and Works Act for consent to develop and operate the Morlais tidal energy project. Menter Môn also applied to Natural Resources Wales Marine Licensing Team for a marine licence under the Marine and Coastal Access Act 2009. Both processes run in parallel with each other. Consent was granted in December 2021.

Consultation was an important element of the process, with statutory consultees on key technical issues as well as with the community and other interested groups.

An ‘Environmental Statement’ (ES) was submitted with the applications. The ES report set out conclusions on predicted environmental effects and proposed mitigation measures that may be required if impacts cannot be avoided. 

Project Progress

The first stage of the project focused on securing consent from Welsh Government and Natural Resources Wales. Community and stakeholder consultation and engagement was key part of this process. The application was submitted in the autumn of 2019 consent was awarded in December 2021.

The second stage of the project will put the necessary infrastructure in place for developers of tidal stream energy devices to deploy their technology in the zone. Implementation will be phased which means devices will be installed gradually to ensure that the development does not negatively impact marine wildlife.

Construction will happen in phases and is subject to close out of conditions specified in the Marine Licence issued by NRW in 2021. Work on land (substation and cable landfall) started in 2022, with work offshore (environmental mitigation and monitoring) starting in 2023.

Key Environmental Issues

An Environmental Impact Assessment (EIA) was prepared as part of the consenting process, based on a scope of work agreed with National Resources Wales and Welsh Government and informed by statutory consultees. 

Independent experts conducted detailed studies to understand the potential impacts of the project during construction, operation and decommissioning stages. The studies included:

  • Marine sediment and water quality
  • Natural heritage, benthic ecology, marine mammals, fish and shellfish, ornithology, terrestrial and coastal ecology
  • Seascape and landscape
  • Shipping and navigation
  • Archaeology and cultural heritage
  • Tourism and recreation

Full details of all relevant consenting documentation, including the supporting EIA are available at the NRW Marine Licence portal: https://naturalresources.wales/permits-and-permissions/permit-applicati…

Environmental Monitoring Indicators 

Monitoring Questions

Table of monitoring questions

Baseline Assessment: Morlais Tidal Demonstration Zone

Receptor Study Description Design and Methods Results Status
Invertebrates Benthic and intertidal ecology Subtidal and intertidal surveys. Grab samples and underwater camera surveys. The impacts on benthic ecology associated with construction, operation, repowering and decommissioning are anticipated to result in changes of minor adverse or negligible significance.
 Completed
Human Dimensions Marine archaeology surveys Geophysical survey with desk study. Through the implementation of embedded and additional mitigation, the effects on offshore archaeology associated with construction, operation, repowering and decommissioning (including cumulative and transboundary impacts) are anticipated to result in impacts of negligible or minor adverse significance.
 Completed
Human Dimensions, Fisheries Commercial fisheries surveys Desk based, radar/visual surveys and fisheries consultation. The vast majority of the impacts to commercial fisheries receptors throughout the various stages of development are likely to be of minor adverse significance. Some potential moderate adverse
impacts are predicted but with successful implementation of appropriate mitigation measures, these will be reduced to minor adverse/negligible significance. 		Completed
Human Dimensions Shipping and navigation surveys Marine traffic surveys with desk study and Navigational Risk Assessment (NRA). With suitable mitigation measures implemented where necessary (such as construction vessel routeing and entry/exit points into the MDZ), impacts were considered to be within acceptable or tolerable risk levels. Completed
Marine Mammals Marine mammal surveys Two year boat based surveys with desk study. Throughout the construction, operation and maintenance, repowering, and decommissioning phases, taking into account the proposed mitigation, the impact on marine mammals is considered to be of negligible or minor adverse significance.

Potential collision risk for bottle nose dolphin with operational turbines predicted to be potentially minor to moderately adverse. 		Completed
Fish Fish and shellfish ecology surveys Desk based surveys. Overall, the assessment concluded that the Project could result in a range of small scale effects on fish and shellfish ecology (such as temporary habitat loss and disturbance). The effects on fish and shellfish ecology associated with construction, operation and decommissioning are anticipated to have impacts of minor adverse significance to all receptors. Completed
Birds Marine ornithology surveys Two year boat based visual surveys with desk study Effects on offshore ornithology are anticipated to result in impacts of minor adverse to negligible significance, with minor beneficial impacts for some species. Completed
Physical Environment Metocean conditions and coastal processes. Metocean data, seabed survey and geophysical data. Overall, the effects of the proposed Project on these processes are predicted to be small scale, localised and temporary. Hence, they are categorised as low, negligible or no impact. Completed
Physical Environment, Water Quality Marine water and sediment quality. High resolution surveys of water depth and seabed topography, seabed texture and features and sub seabed geology. Drop down camera with grab samples, UAV survey and intertidal walkover. Overall, no significant impacts on marine water and sediment quality were identified in the assessment, and through the application of standard measures to reduce the risk of potential pollution, all potential impacts to water and sediment quality are not significant and considered to be small scale, localised and temporary. Completed