In addition to the grid connected wave test site at Billia Croo, EMEC also have a wave test site that is not connected to the grid aimed at providing less challenging conditions for scale prototypes and marine operations. The site provides a more flexible seaspace acting as a stepping stone between the test tank and real sea conditions. The site is located in Scapa Flow, to the south of Kirkwall, and was chosen for its relatively benign waters which reach almost 0.35m significant wave height. The area is 0.4km across and approximately 0.9km in length situated in water depths of 21-25m with a predominant westerly wave regime.
At the site EMEC offers developers the use of a bespoke test support buoy. If required, the device under test will be connected to the test support buoy via two umbilical cables: one for power transmission and the other for control and communications. A purpose-built Test Support Buoy moored on site acts as a power sink to allow load-dumping of any electricity generated as heat dissipated to air. A simulated grid can be made available to support device performance analysis The buoy can relay data by wireless technology allowing developers to monitor performance remotely, as well as dissipating electricity generated by the device. The buoy is also equipped to supply the marine energy devices on test with power and act as navigational aids.
Each test site comprises one berth with pre-laid foundation and attachment points, and an adjacent test area. The pre-laid foundations comprise 5m x 5m x 2m gravity-base frames loaded with densecrete blocks for equipment moorings. The area of seabed is also available for rehearsal or deployment of other tools and techniques.
The EMEC Scapa Flow scale wave test site is situated in the natural harbour of Scapa Flow south of Kirkwall in the Orkney Islands, Scotland. The testing area within the site range from 21-25m water depth.
EMEC holds an overarching site licences, simplifying the consent process within an agreed envelope of activity, including:
- Marine Licence issued by the Regulator, Marine Scotland; and
- Harbour Works Licence issued by Orkney Islands Council (OIC).
A marine licence is required for installation of marine energy converter devices at the scale test site.
A developer wishing to deploy a device at the test site must provide an outline of the proposed project. Developers are requested to provide a Project-specific Environmental Monitoring Programme and Project-specific Navigational Risk Assessment (addendum to site-wide NRA). These documents must also identify any potential device-specific environmental or navigational risks, as well as any proposed mitigation measures or risk controls. EMEC is also required to give OIC at least 21 days’ notice of each new developer wishing to install at its scale sites.
Site selection surveys and environmental studies were carried out in 2009-10. Construction of the EMEC Scapa Flow scale wave test site was completed in 2011 and EMEC welcomed their first client on site in 2012. The EMEC wave test site at Scapa Flow is expected to continue to be operational so long as there is a need for testing in the benign real-sea regime the site enjoys. The following is a list of EMEC clients:
- Energy Bag Device, University of Nottingham - installed 2012
- CorPower Ocean C3 Wave Energy Converter – installed January 2018
Key Environmental Issues
Although some seals have been recorded in the area of the site, SNH have commented that this area is not a site of concern for seals. There have been sporadic sightings of cetaceans within the observation area, in particular Harbour Porpoise and Risso’s Dolphin. Scapa Flow is selected as a proposed Special Protection Area (pSPA) for its important wintering grounds used for feeding, moulting and roosting by non-breeding shag and waterfowl. The key non-breeding qualifying Annex I species of the Scapa Flow pSPA include: Great northern diver, black-throated diver, Slavonian grebe, common eider, long-tailed duck, Common goldeneye, Red-breasted merganser, and European shag. The Red-throated diver is proposed as a qualifying species in the breeding season only. In winter, the Great Northern Diver and Slavonian Grebe are present in Scapa Flow in internationally important concentrations. In relation to these species at the sensitive periods, the key issues to be addressed within developers’ environmental monitoring plans are:
- Displacement due to noise (during installation, maintenance, operation and decommissioning of device)(particularly vessel noise)
- Displacement due to physical presence of device
- Physical harm caused by collision
- Physical harm caused by entanglement in device moorings
- Physical harm caused by noise
Environmental Webpage: http://www.emec.org.uk/facilities/scale-test-sites/
A revision to the Scapa Flow Environmental Description was published in January 2019 and can be accessed here: http://www.emec.org.uk/?wpfb_dl=146.
Mitigation Measures: Where appropriate developers are required to implement their own mitigation measures should activities overlap with sensitive times of the year for marine wildlife.
As the site is not grid connected, no export cable is present.
Used to install anchors and test support buoy
Exact vessel used unknown
Papers, Reports, Research Studies
- Scapa Flow Scale Site Environmental Description 2011
- Scapa Flow Scale Site Environmental Description 2019
- Scapa Flow Wave Test Site: Acoustic Characterisation
- Scapa Flow Scale Test Site Gravity Base Anchors: Marine License Application - Supporting Document
- Scapa Flow Wildlife Observations Methodology
- Preliminary assessment of the conservation importance of benthic epifaunal species and habitats of the Pentland Firth and Orkney Islands in relation to the development of renewable energy schemes
- SSF Scapa Flow Sites - Benthic ROV Survey St Margaret’s Hope. Available here.
Baseline Assessment: EMEC Scapa Flow Non Grid-Connected Wave Test Site
|Receptor||Study Description||Design and Methods||Results||Status|
|Fish||Baseline description of fish in Scapa Flow region.||As with much of UK waters, fish studies of high spatial resolution are currently poorly represented for this part of Orkney. Despite this, it is possible to make general statements based on the location of the site, known seabed conditions, and from existing resources e.g. the Orkney Biodiversity Records Centre.||Fish species that are commonly found in Scapa Flow are typical of north Scottish waters and include pollack (Pollachius pollachius), saithe (Pollachius virens), ling (Molva molva), ballan wrasse (Labrus bergylta) and cuckoo wrasse (Labrus mixtus). Less abundant species include poor cod (Trisopterus minutes), goldsinny (Ctenolabrus rupestris), conger eel (Conger conger) and cod (Gadus morhua), which is widely distributed around Orkney in the summer months. Mackerel (Scomber scombrus) present during their migratory passage past Orkney, may also be found in the more energetic waters of Hoxa sound in the south of Scapa Flow. Other species that may be seasonally present include juvenile and non-spawning adult monkfish (Lophius piscatorius) and gurnard (Triglidae spp.). ||Completed|
|Birds||Bird characterization survey ||Boat-based bird surveys conducted in Scapa Flow between June |
and August 2008. Supplemented with literature review.
|Guillemots, black guillemots and fulmars were the species most often recorded, with greylag geese and European storm petrels in the dominant group of species on some survey occasions. Scapa Flow held the highest populations of redbreasted merganser, red-necked grebe, Slavonian grebe and European shag of all areas of search in Scotland according to Lawson et al. (2015). ||Completed|
|Invertebrates||Initial site selection: determining biota and sediment particle size.||Grab sampling and ROV surveys.||Moderately low energy site. “Sheltered Muddy Gravels” and “Subtidal Mixed Sediments”. |
The infaunal community was composed largely of deposit feeding species (mainly polychaetes and bivalve molluscs), with only a few crustaceans present. Two common species were Lumbrineris gracilis and Thyasira flexuosa which made up approximately 10 - 20% of individuals at all stations.
Aquatera conducted surveys to the west of St Mary’s on the eastern side of Scapa Flow, and reported results that are mostly consistent with the surveys conducted by Moore (2009). The observed habitat resembled the biotope “Loose-lying mats of Phyllophora crispa on infralittoral muddy sediment” (SS.SMp.KSwSS.Pcri), which is not currently list as an Annex I habitat (on the UK Biodiversity Action Plan or on the Scottish Biodiversity List) and no benthic species of conservation importance were identified at the test site during surveying.
|Physical Environment||Initial site selection: Bathymetry commissioned by EMEC to Netsurvey Ltd.||Geophysical bathymetry survey.||Water depths ranged from 15 to 30m across the site approximately 1 m deeper than charted depths.||Completed (2010)|
|Physical Environment||Baseline acoustic characterization||Seabed-mounted hydrophone deployments.||Background noise levels were in line with that which could be expected for this type of shallow water site. Contributions over and above these conditions were then identified, with the major contribution being the natural sounds from wind/waves and precipitation. The major anthropogenic source was shipping noise from distant static and mobile sources. Local shipping traffic also contributed to the sound field, although this was only present for around 7% of the time. Other sounds identified included a thunderstorm, aircraft and various biological sources.||Completed|
Post-Installation Monitoring: EMEC Scapa Flow Non Grid-Connected Wave Test Site
|Stressor||Receptor||Study Description||Design and Methods||Results||Status|
|Habitat Change||Invertebrates||Benthic grab analysis.||Survey samples sieved and analyzed regarding species and abundance||Study undertaken to assist in setting up the scale site, no further work deemed necessary unless additional or different types of infrastructure are proposed. ||Completed|
|Habitat Change||Physical Environment, Sediment Transport, Invertebrates||Bottom sediment type and infauna identification. ||ROV surveys conducted to the west of St. Mary’s on the eastern side of Scapa Flow with three sample sites surveyed to within and around the Scapa Flow test site. ||Substrate: Flat muddy sand substrate with some shells and pebbles. |
Infauna: a large number of tube-dwelling, filter-feeding analids (such as sand masons, Lanice conchilega) and bioturbasive mounds were reported. The tube anemone Cerianthus lloydii and terebellid worms were also observed during surveys. Epifauna included occasional harbour crab Liocarcinus depurator, queen scallop Aequipecten opercularis and the common starfish Asterias rubens. Burrow-like holes in the sediment were observed, as evidenced by the presence of the bivalves - razor shells on the seabed. Serpulid worms occupied ocean quahog, Arctica islandica, and scallop shells.
|Habitat Change||Invertebrates||Biofouling characterization.||Characterization of biofouling present of pre-laid foundations using 3D video survey/mapping||3D model of foundation and associated report.||Completed (2018)|