When the European Marine Energy Centre (EMEC) was established by Highlands and Islands Enterprise (HIE) and its funding partners in 2003, it was with the intention of stimulating and accelerating the development of tidal prototype energy generating devices. As part of the Prime Contracting Framework Agreement, Highlands and Islands Enterprise (HIE) engaged Tulloch Prime Contracting Limited (Tulloch) to undertake the design and construction of the tidal test facility.
The establishment of a test centre for assessing the performance of new and developing tidal energy technology is a strategically important facility for Scotland and the UK. AURORA Environmental Ltd (AURORA) was contracted by Tulloch to undertake the environmental works for the construction and installation phase of the tidal test facility, including a number of baseline studies and the production of an Environmental Statement (ES) to support consent applications. The scope of the Environmental Impact Assessment (EIA) produced for the test site covers the construction, installation and generic presence of the test site, but does not cover the installation and testing of individual prototype devices. In order to be able to assess the impacts of the long-term presence and operation of the site, it was necessary to consider a range of likely potential devices at a generic level. The detailed consideration of individual devices is the responsibility of each developer making use of the site. To this end, EMEC has developed EIA guidance for potential developers in consultation with a wide range of regulatory organisations and local stakeholders.
The lifespan of the project is estimated at 15 years, with individual prototypes being on site for between 6 months and 10 years. Additional devices may be added to each cable in the future, and there is scope to expand the onshore facility within the existing site if required at a later stage.
In 2014 EMEC published an Environmental Appraisal of the site to facilitate the consenting process by reviewing environmental information and providing an appraisal to inform developer licence applications for the deployment of devices.
The Fall of Warness test site consists of eight berths, each with an 11kv seabed cable to export electricity to the onshore substation.The cables are wet-type composite cables consisting of three EPR-insulated stranded copper power cores designed for alternating current, three 2.5mm2 copper signal/pilot trip cables and a 12-core single-mode fibre-optic bundle. The cable is then armoured with two layers of galvanised steel wire. Cables were provided by AEI (wave test site cables) & Pirelli (tidal test site cables).
The cables were laid as standard sub-sea cables on the sea bed. As the cables approached the shore, in 15m of water, ductile iron cable protectors were attached. At the low water spring tide mark, each passes into a trench dug 12m into the seabed and beach. Onshore, the cables are fed into a manhole and then into the substation.
At the seaward end, each cable, when not occupied by a developer, is terminated using a specially designed connector provided by J+S Ltd, which allows EMEC to carry out planned condition monitoring of any cables not in use by developers. These terminators can, if required, be converted into splices to enable developers to use umbilical cables to attach their devices to the cables.
The onshore substation is a single storey building covering an area of 30 x 5.5m. Inside the substation, each cable terminates at an 11kV circuit breaker, along with the tripping cable. The fibres are terminated in the communications area of the substation. The electrical output performance of each of the devices is measured by equipment within the substation and transmitted to the data centre. EMEC then analyse the quality of the electricity to demonstrate that the devices can provide a smooth and reliable supply of electricity to the grid. The metered data is also provided to the developer through the Supervisory Control and Data Acquisition (SCADA) system and the power data is logged in the data historian to be made available for historical trending. We ensure the confidentiality of the data collected.
Vessels used in the installation of the EMEC tidal test site are:
Swathe bathymetry – site characterisation surveys
Exact vessel used unknown
ROV seabed surveys
Exact vessel used unknown
Cable lay vessel
Installation of sub-sea export cables
The EMEC Fall of Warness grid-connected tidal test site is situated off the island of Eday where the Atlantic Ocean meets the North Sea, approximately 20km north of Kirkwall in the Orkney Islands, Scotland. The eight test berths on site range in depth from 12m to 50m.
The European Marine Energy Centre (EMEC) has been accredited with the UK Accreditation Service (ISO 17025) since 2005. EMEC has been granted the consents required to install an agreed ‘envelope’ of device types at these sites.
Licences held by EMEC include:
- Town and Country Planning (Scotland) Act 1997
- Crown Estate Act 1971
- Food & Environment Protection Act 1985 Part II Deposits in the sea (FEPA
- Coast Protection Act 1949 (section 34) (CPA)
- Electricity Act 1989 (section 36)
Each developer is required to submit device-specific information to support amendment of these consents to allow installation of their device. This information includes a project summary and details on how the specific device details align with the EMEC environmental description and navigational risk assessment.
Construction of the EMEC Fall of Warness tidal test site was completed in 2005 and the facility was commissioned shortly afterwards. EMEC welcomed their first tidal developer client in 2006. Two new subsea cables were installed at the test site in 2010 bringing the total number of EMEC-owned test berths to seven. All 8 berths are now contracted and options for accommodating further test devices are being considered. The following is a list of all EMEC tidal clients who have deployed devices at the Fall of Warness test site:
- Turbine, OpenHydro
- Installed December 2006, Ongoing
- Deepgen, Alstrom (formerly Tidal Generation Ltd)
- Installed September 2010, Decommissioned 2016
- SR250, Scotrenewables Tidal Power Ltd
- Installed March 2011, Decommissioned 2013
- AR1000, Atlantis Resources Corporation
- Installed August 2011, Decommissioned 2012
- HS1000, Andritz Hydro Hammerfest
- Installed December 2011, Decommissioned April 2015
- HyTide 1000, Voith Hydro
- Installed September 2013, Decommissioned February 2015
- SR2000, Scotrenewables
- Installed October 2016, Ongoing
- Installed October 2016, Ongoing
- CoRMaT 500, Nautricity
- Installed April 2017, Ongoing
- T2 Array, Tocardo
- Installed May 2017, Ongoing
- Plat-O, Sustainable Marine Energy
- Installation date unconfirmed
The following issues were identified:
- Modification to coastal processes (e.g. water movement and sedimentation patterns)
- Disturbance/modification to benthic habitats and communities due to cable laying in inshore waters.
- Disturbance (noise and physical presence) to wildlife including birds, cetaceans, turtles, pinnipeds and otters
- Pollution of water column from antifoulants, lubricants and hydraulic fluids.
- Ongoing minor disturbance to seabed communities in the immediate vicinity of the routes where the cable is laid on the seabed.
- Seabed disturbance/modification during foundation installation and during device installation/removal e.g. anchors etc.
- Disturbance (noise and physical presence) to local fish, seabird, seal, otter and cetaceans populations as a result of device installation.
- Loss of water current energy from the marine environment due to presence/operation of test devices may result in sedimentation and habitat and community modification and increased stratification in the water column.
- Foundations could affect seabed current flow and consequent sedimentary processes.
- Seabed scour around device foundations
- The effect of tidal turbines on seals and cetaceans is at present unknown as is the extent to which these populations pass through the waters of the Fall of Warness
- Wildlife entanglement/entrapment and collision with device blades e.g. diving bird populations, cetaceans (in particular the harbour porpoise), seals (in particular pups)and otters present in the area.
- Devices that break the sea surface may attract roosting birds and provide a seal haulout
- Electrical and electromagnetic effects – wildlife interactions
Of these environmental issues, those relating to seabed and coastal processes, water column contamination, and disturbance to wildlife were screened out due to the residual impact being classed as negligible. The only remaining environmental issue was:
- Disturbance/modification to benthic habitats and communities as a result of cable-laying in inshore waters.
Developers are not required to undertake a baseline seabed survey as this was carried out as part of the ES. They are however required to undertake a seabed survey post-decommissioning to assess the effect of the device upon the seabed. Other commitments are defined in the Guidance for Developers Document.
Environmental Webpage: http://www.emec.org.uk/services/consents/
- Construction activities were planned to occur for 7 consecutive days in August, towards the end of the bird breeding season (cormorants) and before the start of the grey seal pupping season thus minimising any disturbance;
- Any evidence of wrecks encountered during cable laying were to be reported immediately to the County Archaeologist;
- Recognised marine standard materials held on vessel(s) and recognised marine working standards and regulations were applied;
- A Navigation Risk Assessment was undertaken and the site was marked on the appropriate charts providing the mariner with adequate information;
- The cable laying vessel complied with the International Regulations for Preventing Collisions at Sea (COLREGS) and displayed the appropriate lights and marks for a vessel restricted in her ability to manoeuvre;
- The works were promulgated by appropriate Notices to Mariners and Navigational Warnings;
- Consideration was given to test berths being clear of the adverse weather ferry routes were possible (in the case of the surface piercing device), and away from the main transit route (in the case of the buoyant surface device);
- Appropriate marking, lighting and aids to navigation to be specified for all surface piercing devices;
- EMEC have implemented a wildlife monitoring programme to in an attempt to investigate the effect of device presence on marine wildlife; and
EMEC has been involved with a number of other research institutions to identify the knowledge gaps and initiate research aimed at addressing these.