Site selection, feasibility assessments and environmental studies began in 2006 and a newly created development company, SeaGeneration (Wales) Ltd, was set up in 2008 as a joint venture between Marine Current Turbines (MCT) and RWE npower renewables to develop the project. MCT was subsequently bought over by tidal industry leader Atlantis Resources Ltd in 2015. The location for the proposed array was a 0.56 km2 site between the group of rocks and islands known as the Skerries and Carmel Head. The site is less than 1km from the Anglesey coast and is characterised by water depths of around 20 to 40 m. Its close proximity to Holyhead made the site suitable due to access to good port facilities, the national grid and transport connections. The proposed array was planned to consist of up to 9 SeaGen devices and have a total installed capacity of up to 10 MW. The array was planned to operate for up to 25 years and serve as a test case for the development of the technology in multi device arrays.
The technology used was to be the Atlantis AR Series Turbines, which are commercial-scale horizontal axis turbines designed for open ocean deployment in the most energetic marine environments on the planet. The Atlantis AR turbines are currently available in a 1.5 MW AR1500 system designed by Lockheed Martin Corporation, and the 1.5 MW SeaGen U system, both with active pitch configuration and yaw capability. AR series turbines are deployed using a patented stab system that facilitates rapid deployment, retrieval and subsea connection to shore.
Key design Features of the AR tidal turbine systems include:
- A single axial flow rotor that drives a generator via a gearbox - much like a wind turbine
- Complex electrical infrastructure such as converters are located on the shore to reduce the amount of electrical equipment contained offshore
- Stab system enables rapid retrieval without having to recover the foundation structure - for ease of maintenance
- AR series turbine systems produce fully grid compliant power
A single 33 kV export cable was to be laid to transport generated power to the shore. Two possible cable corridors 500 m in width were identified and assessed, with three methods considered
for the installation of the export cable. The first option involved laying the cable directly onto the seabed; this method would have left the cable vulnerable to physical damage from fishing gear and rocks / coarse sediment circulated by the strong currents. The second available option was trenching the cable using a plough. It was likely that this method would only take place in the intertidal sections of the cable route. The final option was directional drilling. A directional drill would have created a hole in the bedrock from the land to a point approximately 1km from the proposed array. The cable would then either be entrenched or covered with protective mattresses for the remainder of its route.
Between Skerries and Carmel Head on mainland Anglesey.
Coordinates: The four corners of the cancelled development site are labeled as A1, A2, A3 and A4:
In March 2014 an EIA consent decision under the Marine Works (Environmental Impacts Assessment) Regulations 2007 was issued to SeaGeneration (Wales) Ltd by Natural Resources Wales on behalf of the Licensing Authority. This consent decision can be accessed here.
|Section 36 (Electricity Act) Consent||N/A||N/A|
|Marine Licence (Marine (Scotland) Act) Consent||N/A||N/A|
|Licence to Disturb Marine Species||N/A||N/A|
|Licence to Disturb Basking Shark||N/A||N/A|
|Town and County Planning Permission||N/A||N/A|
Consent for the project had been granted and a grid connection for 2015 secured, with onshore work underway including feasibility studies and assessment of options for an export cable route, landfall point and substation location. However, the project was shelved in September 2014 after MCT/Siemens suspended the project with no re-start date.
However, in April 2015 it was announced that industry leader Atlantis had reached an agreement to acquire the entire issued share capital of the Bristol-based tidal business MCT from Siemens AG in an all share deal. This purchase included a portfolio of six projects including the Skerries scheme.
Despite the purchase of MCT’s/Siemens’ portfolio of sites by Atlantis, it was announced in March 2016, that they would relinquish the Agreements for Lease that it held at two of these sites, one of which was Anglesey Skerries (the other being the Kyle Rhea site in Scotland). Ownership of these sites has now returned to The Crown Estate.
Atlantis stated that they wished to prioritise other sites that are currently under construction and closer to reaching financial close.
The following potential impacts were identified as being potentially significant during the EIA:
- Erosion or accretion of shoreline at landfall within SSSI
- Operational noise causing disturbance and barrier effect to marine mammals
- Collision risk between marine mammals and device
- Operation of the device causing displacement of fishing activities
- Device presence disturbing seascape from a number of view points
- Collision risk of vessels transiting through the area
The following mitigation measures were outlined in the Environmental Statement:
- Scour protection will be considered for areas where significant scour is recorded to prevent any further erosion and associated release of potential suspended sediments.
- Any trenching will be backfilled immediately to reduce impact of suspended sediment on benthos, fish and shellfish during construction.
- Marine mammal observer will be present during construction to identify disturbance or injury to marine mammals, basking sharks and marine turtles caused by noise or collision with vessels.
- Deploy and monitor strategy to protect marine mammals from the effects of operational noise, habitat exclusion, collision risk, and barrier effect of the array will be developed.
Environmental webpage: http://www.seagenwales.co.uk/environmental-aspects/