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.

West Islay Tidal Project Energy Park

Description

The development site lies approximately 6km off the  Rinns of Islay, Islay, Inner Hebrides, Scotland and covers approximately 2 km2 of seabed. The long term goal is to expand the array. In 2009, a two-year marine mammal and bird survey campaign was commenced in the area. Upon the completion of these surveys in 2011, an Agreement for Lease for the development area was granted by the Crown Estate. 

The site development proposals are based on a technology neutral approach to minimise development risk. It is not possible to adopt a completely neutral approach given the physical constraints and resources at the site; therefore a design envelope has been developed based on generic design philosophy. The design envelope includes seabed mounted devices that are either surface piercing or non-surface piercing with horizontal axis turbines. The design envelope considers twin and single horizontal rotor devices up to 20 m diameter. 

Mooring and Foundations:

There are several possible methodologies for securing the turbine in position, these include a gravity base, piled or pin-piled fixed base. The MCT/Siemens device incorporates two turbine units attached to a lifting cross arm mounted on a steel tower anchored in the seabed (the Seagen S). Alstom’s turbine is mounted on a tripod support structure pinned to the seabed. Hammerfest propose a similar tripod foundation but with ballast used to keep the structure in place.4 Alternative floating support structure systems have also been considered as part of the EIA. 
 
Export Cables:

The inter-array cabling will be marshalled and exported to shore via up to three 33kV subsea export cables, landing at Islay. A number of routes and landfall locations  were/ continue to be considered. The preferred option at the time of Marine Consent application and the one which is described within the Environmental Statement (ES) is to route the export cable east from the tidal park to a landfall location at Kintra on Islay. 

Onshore Infrastructure:

The existing infrastructure on Islay will need to be upgraded to facilitate the power transfer from the project to the grid on the mainland which will require deep reinforcement.

Vessel Spread:

The number of vessel movements and type of vessels used will depend on the selected turbine technology.4 This information will be provided in the Construction Method Statement once the final design has been completed; however the installation works is most likely to be carried out by either jack up vessels, dynamic positioning vessels or heavy lift vessels. The vessels that are likely to be used are outline in the following table.

 

Type of installation 
vessel

Option 1:
Large size Jack up barge as installation vessel

Option 2:
Medium size Jack up barge as
installation vessel

Option 3:
Dynamic positioning scenario

Size of vessel

150m x 45m

68m x 38m

155m x 30m

Footprint of mooring system

4 triangular lattice spuds with circa 140m2 spud area

4 circular spuds ca. 10m² spud area
(possibly extended with spud cans)

Dynamic positioning holding a footprint of +/- 5m

No. tugs required

Jack up vessel is typically self-propelled,

Jack up vessel is typically self-propelled, but possible single tug required for initialpositioning (30x22m)

n/a

Anchor handling vessel

n/a

n/a

n/a

Flat top barge (to bring out large items)

n/a

n/a

n/a

Crew change support vessel (vessel length)

Up to 26m

 

Up to 26m

Install vessel

100m x 50m

 

100m x 50m

SeaGen unit installed by

Same vessel

JUP vessel in case SeaGen S unit split up
into multiplesections or by HLV (Heavy
Lifting Vessel)

DP2 vessel in case SeaGen S unit split up into
multiple sections or by HLV 4

 

Location

6 km South West of the Rinns of Islay, Islay, Inner Hebrides, Scotland.

Licensing Information

An application for consent was submitted in 2013. Marine Scotland have consulted on the application and will make recommendations in due course. 

Licence Competent Authority Reference
Marine Licence (Marine (Scotland) Act) Marine Scotland https://marine.gov.scot/data/west-islay-tidal-energy-park-marine-licenc…
Section 36 (Electricity Act) Consent Scottish Ministers TBC
Licence to Disturb Basking Shark Marine Scotland TBC
European Protected Species Licence Marine Scotland TBC

Project Progress

In October 2011 The Crown Estate granted an Agreement for Lease. A suite of environmental baseline characterization surveys to inform EIA commenced in 2011.  The Environmental Statement was published in 2013 in support of an application for statutory consents. The project was co-developed from 2014 to 2019 by DP Energy and Bluepower through SPV West Islay Tidal Energy Park Ltd. (WITEP). From 2020, WITEP was 100% owned by Bluepower.

This WITEP project no longer has an active lease site within Scotland.

Key Environmental Issues

Several potential impacts were identified during the Environmental Impact Assessment, however only the following were deemed to be potentially significant:

  • Mortality or death of marine mammals as a result of collisions with operating turbines; and
  • Temporary loss of fishing grounds due to the construction of the development.

The below baseline assessments were undertaken (or commissioned by) the developer to inform baseline characterisation.

The mitigation and monitoring measures in the Post-Installation Monitoring table are proposed within the project ES. The project team, along with Marine Scotland and other key stakeholders are currently preparing a Preliminary Environmental Monitoring Plan (PEMP) which will outline the proposed monitoring strategy in more detail.
 

Mitigation measures:
A number of key mitigation and best practice measures have been proposed throughout the ES. These are as follows:

  • Development of an Environmental Management Plan (EMaP) to be agreed with SNH and Marine Scotland, following submission of this ES. The EMaP will be a working document detailing the environmental actions highlighted in the ES, all activities to be carried out on site, responsibilities for those activities, environmental risks and the management protocols to be put in place to control these, as well as identification of personnel responsible for each element of the EMaP;
  • An Environmental Monitoring Programme (EMP), to be agreed with Marine Scotland (MS) and Scottish Natural Heritage (SNH);
  • A detailed Construction Method Statement (CMS) and a Pollution Control and Spillage Response Plan to be prepared and agreed with SEPA, SNH and MS-LOT prior to commencement of construction;
  • All work will be undertaken to an overarching Health, Safety and Environmental Management System (HSEMS), which will include the CMS, the PIRP and the EMaP. The project will be supervised in accordance with the Construction Design and Management Regulations (2007); and
  • Pollution Control and Spillage Response Plans to be developed and included in the EMaP.

Papers, Reports, Research Studies

Project applications and supporting documentation: 

Reports:

Baseline Assessment: West Islay Tidal Project Energy Park

Receptor Study Description Design and Methods Results Status
Physical Environment Benthic ecology characterisation by Envision Mapping Drop down video (DDV) survey, epibenthic beam trawls and benthic grab sampling, as well as intertidal biotope surveys Mixed sediment habitats were observed along the western export cable route. Biotopes found at the Tidal Site and along the Western Export Cable Route were then superimposed onto both UKSeaMap 2010 predicted habitats and geophysical data results in order to estimate the extent of the biotopes. Completed 2012 (between July and August)
Marine Mammals Vessel based visual survey by SAMS Research Services Ltd. Monitoring was conducted during monthly boat-based surveys using both visual and acoustic methods. In addition, a seabed mounted passive acoustic recorder was also tested. The variety of marine mammals identified using the waters immediately west of Islay are very much as would be expected for this site and habitat. Minke whales and basking sharks were not observed in the development site in summer. Monthly surveys were too sparse to confirm their absence. In general the sightings (and detection) rates of all species were not especially high, particularly in comparison to the number of marine mammals seen on the summer legs between northern Islay and Colonsay. The comparatively low detection rate for harbour porpoises in the centre of the development site was also evident on the moored porpoise detector. However, detection rates of some species (harbour porpoise and the two seal species in particular) appeared to be higher in particular areas of the survey area, with porpoise click events apparently concentrated in the southern half of the survey area (particularly along the ridge southwest of Portnahaven) and sightings of seals (especially grey seals) concentrated in the south eastern portion of the survey area. As clarified above, the small sample sizes mean that this spatial variability cannot currently be rigorously assessed, but it is suggestive of small-scale heterogeneity in habitat use. Completed 2011 (2 year survey from November 2009 to November 2011)
Marine Mammals Full otter survey of the development area A full otter survey was conducted following standard methodology and using an appropriate field guide. No evidence of an otter holt was recorded during the course of the survey. However, an otter spraint was recorded outside a rabbit burrow on the bank of Cornabus Burn. Completed (15th and 16th September 2012)
Fish, Invertebrates Fish/shellfish ecology beam trawl surveys Conducted using a 2m beam trawl fitted with an iron tickler chain and 24mm mesh net. A total of 8 tows were undertaken lasting from 5 to 13 minutes in length, at a speed over ground of between 2 and 3 knots. Total swept areas thus ranged from 802m2 to 1845m2. The trawls were undertaken along the Western and Eastern Export Cable Routes. The fish and shellfish communities at the Tidal Site and along the Western Export Cable Route to Islay are characterised by relatively low abundances of largely common and widespread species suited to a coarse rock/boulder strewn substratum, with strong water movement. There is no evidence that the Tidal Site or Western Export Cable Route to Islay are important nursery or spawning grounds, although spawning and nursery grounds for some species are reported within approximately 20 nautical miles of the Tidal Site. Completed 2012 (between July and August)
Birds, Seabirds Ornithology - Vessel based transect survey The European Seabird at Sea (ESAS) survey method was used as this is the most appropriate method for surveying relatively large areas offshore. Surveyors recorded all birds seen within 300m of the transect line (to one side of the survey vessel). The species, number, plumage, activity, flight direction, distance-band from the boat (0-50m; 50-100m; 100–200m; 200-300m), and whether flying birds were ‘in transect’ at the time flying-bird snapshot were taken. In the summer months (April to August) additional survey work was carried out along two corridors stretching from the main survey area to the North Colonsay and Rathlin Island SPAs respectively. A total of 11 seabirds species were regularly recorded (defined as at least two records) using the development area and 1km buffer during the two years of baseline surveys. Of these, fulmar, gannet, and Manx shearwater were commonly seen but the great majority of individuals were in flight apparently transiting through the area. Common guillemot and razorbill were both reasonably common through the year and at times in the winter occurred in relatively large numbers. Completed 2011 (2 year survey beginning in October 2009)

Post-Installation Monitoring: West Islay Tidal Project Energy Park

Stressor Receptor Study Description Design and Methods Results Status
Collision Birds Collision risk survey Monitoring the response of diving auks to turbine rotors and provide data on collision risk would also be desirable. However, at this stage it is not clear how this may be practically achieved. Planned
Displacement Birds, Seabirds Survey to quantify displacement Collection of boat-based survey data using the same method during the installation and operational phases would potentially provide a means to measure the extent of any seabird displacement response to the development. Monitoring should focus on the species rated as having or medium EIA priority and SPA qualifying species for which potential LSE has been identified. Planned
Collision Marine Mammals Statistical feasibility study to understand collision risk for marine mammals and basking sharks. Proposed to undertake detailed statistical analysis based on the occurrence of species at the site and the scale of change anticipated, to determine feasible monitoring strategies at the site. The results of this study will then need to be discussed relative to the anticipated risks at the site to determine the precise scope of the on-going monitoring strategy. NA Planned