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.

SEM-REV Sea Test Site

Description

The test site occupies approximately a 1 km2 test zone area and is fully instrumented and monitored. The test site includes a 8 MVA power cable connected to the national grid through a new 20kV onshore substation to the local electricity distribution grid ENEDIS. The SEM-REV is a fully fitted wave and wind energy test facility intended to test and improve the efficiency of Wave Energy Converters (WEC) and Floating Wind Turbine (FWT) at a prototype stage of development. The facilities for monitoring and controlling the systems are currently available at the site. Optical fibers are included in the export cable for data transmission and for control of MRE. Since 2015, CN has installed a HUB subsea multi-connexion system. This device connects on one hand the electrical export cable and on the other hand could be connected with several connection cables of future prototypes. 
 
The FWT FLOATGEN was installed in April 2018 on SEM-REV and it has been producing on the grid since September 2018. CN has installed in August 2019 another prototype, the WEC WAVEGEM. 
 
Support for this project comes from CAPEX: Investment of 19M€ (VAT included) – 100 % Public funding; CPER Region Pays de la Loire (2007-2013). French Government ANR (2014-2019); and OPEX: Co-funding on collaborative research projects, Services, subsidies.

Location

The site is located 12 nautical miles off the north coast of Le Croisic in Pays de la Loire, at France (West coast). Water depth is 32 to 36m LAT with a maximum tidal variation of 6.2m. 

North: 47°14.70’N – 2°46.58’W 
East: 47°14.34’N – 2°46.08’W 
South: 47°13.94’N – 2°46.88’W 
West: 47°14.34’N – 2°47.38’W

Licensing Information

Concession on the maritime public domain (accepted July 2011 and confirmed January 2014). Permitting process completed for multi-technologies on 2014.

Project Progress

The test site has been operational since the consents were approved in July of 2011 for WEC and in January of 2014 for floating wind. Full electrical connection was finalized in October of 2012. The subsea hub connection system was launched in August 2015. SEM-REV is currently hosting two prototypes, the FWT FLOATGEN and the WEC WAVEGEM.

Key Environmental Issues

The environmental monitoring program of the SEM-REV test site is dual. It comprises both:

  • a mandatory monitoring as part of the legal requirements associated to the permit granted to occupy the Maritime Public Domain;
  • a complementary monitoring developed by CN and organized in research axis on the marine environment and possible environmental impacts.

The mandatory monitoring covers the following environmental stressors and receptors: 

  • Generation of noise,
  • Generation of electromagnetic fields,
  • Benthic habitats and communities alongside the electric cable and on the test site, 
  • Record keeping of every products and materials used, 
  • Tracking in XYZ position (3D displacements) of the electrical cable relatively to the moveable sediments, and of the protective mattresses installed over a small portion of the cable.

The complementary monitoring supplements the mandatory monitoring by targeting other sensors that may sustain significant environmental impacts:

  • Physico-chemical compartment: waves, currents, tides, winds, hydro-sedimentary dynamics, sediments and water quality; 
  • Biological compartment: biofouling, fish and pelagic invertebrates and marine megafauna;
  • Human compartment: sea usages and activities, safety and landscape.

The objective of the post-installation monitoring program is: 

  • To measure the real impacts of the FWT FloatGen and the WEC WAVEGEM prototypes,
  • To compare them to the expected impacts,
  • To evaluate the effectiveness of the mitigation and improvement measures selected.

This environmental management programme is a live document likely to evolve as the project progresses.

Environmental Webpage: https://sem-rev.ec-nantes.fr/suivi-environnemental/

Papers, Reports, Research Studies

Papers and Reports:

Conference Presentations: 

  • Le Crom, Y. Perignon, C. Berhault, J.B. Saulnier, Extreme sea conditions in shallow water: estimations based on in-situ measurements, OMAE2013-10752, Nantes, June 9th to 14th, 2013
  • Le Crom, C. Berhault, G. Le Bihan, SEM-REV feedback from the marine renewable energy test site, Thetis, Cherbourg, April 9th to 10th, 2014
  • Le Crom, C. Berhault, From Lab to reals sea conditions - How to support MRE development, Atlantic Power Cluster - Final Conference, Santander, July 3rd, 2014
  • Le Crom, G. Le Bihan, H. Lugez, Marine Operation Review: Feedback on the implementation of the SEMREV test site for Marine Renewable Energy, ICOE'2016, Edimburg, February 22nd to 26th, 2016
  • M. REYNAUD, Population dynamics of blue mussel Mytilus edulis on buoys and their mooring lines installed on the SEM-REV offshore test site (French Atlantic Coast) to provide a reliable database required for engineering marine renewable energy technologies, 2nd International Symposium on the Advances in Marine Mussel Research, Sète, September 8th, 2017
  • M. REYNAUD, SEM-REV multi-technology sea test site of Central Nantes - Environmental monitoring, GDR CNRS 3763 MRE, Saint-Nazaire, October 20th, 2017
  • M. REYNAUD, Environmental monitoring on the SEM-REV sea test site (Nantes – French Atlantic coast), Environmental Interactions of Marine Renewable Energy Technologies 2018, Kirkwall, April 25th, 2018
  • M. REYNAUD, Environmental monitoring of the SEM-REV sea test site. WeAMEC Meeting « Interaction of MRE with the marine environment », Nantes, February 8th, 2019
  • M. REYNAUD, Environmental monitoring of the SEM-REV sea test site (Nantes – French Atlantic coast), OCEANEXT2019, Nantes, July 4th, 2019
  • C. SPRAUL, H-D. PHAM, V. ARNAL and M. REYNAUD, Effect of Marine Growth on Floating Wind Turbines Mooring Lines Responses, 23rd French Congress of Mechanics, Lille, August 28th to September 1st, 2017
     

Collaborative projects (EU and French Projects): 

  • MOREDATA (wave and current statistics), 
  • FLOATGEN (floating wind turbine protoptype), 
  • OMDYN (health  monitoring of dynamic cables), 
  • ABIOP (biofouling development and impact on MRE components), 
  • FORESEA (tests of MRE components in real conditions). 
  • SOWFIA
  • MARINA PLATFORM
  • MARINET
     

Baseline Assessment: SEM-REV Sea Test Site

Receptor Study Description Design and Methods Results Status
Reptiles Resident sea turtle species presence. Bibliographic data. None of species are considered to be resident. 2 species could be observed but observations are very rare. Completed
Physical Environment Waves, current and wind fields analyses. Waves statistics model and weather predictions for marine operation; resource prediction. On site measurements data since 2009 and Metocean specifications for prototypes design.
Underway
Physical Environment Oceanographic and meteorological conditions. Measurements of waves, currents and wind; on site measurements data since 2009. Waves statistics model, weather down prediction for marine operation, and resource prediction. West Waves with monthly occurrence: Hs = 5.5 ; Tp = 14 s ; Dp = 270°; currents: oriented South-West, between 10 and 50 cm/s; mean wind velocity: 7.5 m/s (1h, 10m); extreme wind (50years): 29 m/s (1h, 10m)
 Completed
Physical Environment, Sediment Transport Studies of sediment quality and sedimentary dynamics. Sampling of sediment (with grab or core) for geophysical and chemical analysis; Bathymetric and side scan sonar survey; Hydrosedimentological models. Medium sand to fine sand (0.2-0.5 mm); Bathymetry: 32 m to 36 m LAT; Sediment transport levels are low with no contaminant pollution detected. Completed
Physical Environment, Water Quality Water quality analyses. Bibliographic data: Ifremer monitoring. In 2016, the Water Framework Directive (WFD) described the FRGC45 (Baie de Vilaine) and the FRGC46 (Loire) water mass as mediocre. Completed
Human Dimensions, Navigation Marine traffic surveillance and safety procedures. Marine traffic statistics, Accident statistics, Risk analysis modelling. Not yet available. Underway
Marine Mammals Resident marine mammal species presence. Bibliographic data. None of species are considered to be resident, 7 species could be observed. Completed
Human Dimensions, Fisheries Fisheries community study. Bibliographic data. No nursery area for species of commercial interest at test site. Completed
Birds Avifauna community presence. Bibliographic data. 28 species could be observed: some species are present all year with stable effectives while others have attendance peaks. Completed
Terrestrial Mammals Chiropterans species presence. Bibliographic data. 18 species species could be observed at sea. Completed
Invertebrates Impact of cables and mooring systems on marine life, and biofouling development on that infrastructure.
Survey methodology to follow impact of MRE components (mainly high power cables) and used protocol to quantify biofouling (in space and time).
 Specific subsea monitoring system (MOSAIC) for permanent measurements and observations; report on biofouling development on SEM-REV.
Finalizing protocol to issue annual report on environmental impact. ABIOP project (biofouling) starting in 2017.
Human Dimensions, Visual Impacts Landscape/visual impacts assessment. Photomontage of visual impacts. Low visual impact. Completed
Invertebrates Benthic community studies. Water Framework Directive (WFD) protocol: 6 sampling stations, 2 on the sea test site and 4 along the electric cable
& bibliographic data.
 In 2009 : 5 sampling stations with good ecological status; 1sampling station with poor ecological status.

No algae at the sea test site. 		Completed
Human Dimensions, Stakeholder Engagement Marine uses and users. Bibliographic data. Low impact on other nautical activities and no cultural heritage near the test site. Completed
Invertebrates Plankton community presence. Bibliographic data. Phytoplankton: Good ecological status. Completed

Post-Installation Monitoring: SEM-REV Sea Test Site

Stressor Receptor Study Description Design and Methods Results Status
Changes in Flow Ecosystem Processes Monitoring of temperature, conductivity, turbidity and chlorophyll a and impact of dissolution of sacrificial anodes. Bibliographic data, deployment of a multi parameter probe, measurement of metallic trace elements concentration in Mytilus edulis. Completed for TC2 Focus project (2018-2021).
 Not yet publicly available. To date, no pollution in TME has been detected on SEM-REV through the monitoring carried out mussel meat (Mytilus edulis) or sediment. The results of TME measurements in mussel meat may show variations depending on the samples. The measured levels are broadly equivalent values observed at other regional monitoring points. Observed differences between sampling campaigns are explained more by the physiology and age of the individuals taken only by a change in the quality of the environment. TME concentrations in sediments do not reveal any proven contamination. Regular and long-term monitoring will make it possible to monitor these developments. Underway since 2018
Human Dimensions, Visual Impacts Monitoring of visual impacts. Confrontation of photomontages in EIA to reality. The coastline of the study area is very diverse. It is marked by an alternation of zones and highly anthropogenic areas that are vectors of perception. At sea, the The force line of the horizon is a very strong structure and symbolism. The synthesis of the different factors that make up the landscape (relief, geology, urbanization, vegetation, etc.) vectors of perception, etc.) have made it possible to define the most sensitive sectors from a point of view landscape. These most sensitive areas are the beaches and rocky coasts of Le Croisic, the islands of Hoëdic, Houat and Belle-Ile. Landscape analysis and photomontages prior to the installation of the FLOATGEN floating wind turbine identified the coastal areas from which the wind turbine is visible. A study (photographs) will be carried out in order to compare the photomontages with reality. Completed 2021
Human Dimensions, Navigation Marine uses and user assessment. Monitoring of vessels around test site (frequency, activities). Acquisition on vessels data with AIS around and intrusions into the sea test site. Underway since 2013
Noise Fish, Marine Mammals Determination of the acoustic footprint of all phases of the prototype life cycle and its impact on marine organisms. Deployment of passive autonomous recorders and acoustic modelling. Completed for the installation and operation phases (2017 & 2018): SEAc project (2017-2018), decommissioning phase planned. An overall emergence of less than 10 dB ref 1μPa²/Hz was demonstrated between measurements carried out during the baseline state and the measurements carried out during the operational and maintenance of the FLOATGEN demonstrator, with medium to 113.2 dB ref 1μPa²/Hz. Physical characteristics of the noise emitted by FLOATGEN A first analysis of the estimation of the acoustic gauge of the FLOATGEN floating wind turbine a maximum overall level of 140.6 dB ref 1μPa²/Hz @1m under the production at 100% of its maximum capacity. It has two main signatures, Continuous low-frequency vibrations due to vibrations from the wind turbine and components impulses due to anchor lines. Completed for the installation and operation phases, planned for decommissioning.
EMF Invertebrates Impacts on benthic communities (endofauna and crustacean) and biocolonisation. Installation of electric and magnetic sensors and temperature probe. Began with 2017 SPECIES project (2017-2020). The electromagnetic fields (EMF) measurements of the reference state show an electric field amplitude of the order of -40 to 20 μV/m and 45.1 to 45.65 μT for the magnetic field. These signals correspond to naturally occurring variations (swells and currents, natural variations in the magnetic field) and of anthropogenic origin, such as the movements of the instrument in water. The connection cable is also visible in the magnetic field measurements, due to magnetization of its metal armor, and on electric fields with an increase in Fluctuations caused by conduction by the cable armor of an original electrical signal terrestrial. Completed
Habitat Change Marine Mammals Monitoring of presence and activities of marine megafauna and impacts to reef and barrier effects. Bibliographic data and acoustic data observations during maintenance operation for EOGP project (2015-2017) SEAC project (2017-2018).
 Not yet publicly available. Underway since 2015
Habitat Change Birds Recording of interactions between birds and wind turbines.
 Currently, the monitoring of avifauna and bats is opportunistic. Observations are noted and reported almost systematically by personnel on board during marine operations on-premise. Since March 2020, image captures have been carried out routinely and continuously from surveillance cameras installed on the float of FLOATGEN.

 A total of 28 species of seabirds and coastal birds have the potential to frequent the site. SEM-REV, whether in the foraging phase or when travelling. The three taxa The majority observed (65% of the data) are: Gulls (Laridae sp. – dominant species: Herring Gull, Larus argentatus), Common Murrelet (Uria aalge) and Balearic Shearwater (Puffinus mauretanicus) (Fortin & Gélinaud, 2012; Fortin et al., 2014). According to the bibliography, a total of 18 species of bats are likely to frequent the site SEM-REV trials, especially during migration periods (spring and fall). During the work phase, our observations show attraction effects on bats and bats. Northern Gannets. Plausible causes of attraction are identified as the lighting of the or the agitation generated on the surface by thrusters, in particular. In the operational and maintenance phase, a total of twelve dead birds of various species was identified in the vicinity of the FLOATGEN wind turbine (September 2018 to December 2020). Causes However, the number of deaths remains undetermined for all cases (natural causes such as exhaustion). or disease, collision, entrapment, etc.), and the frequency and means of limited observations. These figures should therefore be taken with great caution. A specific research effort will be carried out in the coming months on this compartment, in order to Accurately determine the interaction of the wind turbine with birds. This issue requires a specific methodological and technological development, and the ADEME PIAFF&CO project, in will allow these issues to be addressed in a more systematic way. Completed
Habitat Change Fish, Invertebrates Fisheries resources and pelagic invertebrates. Monitoring of reef and barrier effects Bibliographic data, acoustic data, and observations during maintenance operation.
 The EchoSondeBis research project is currently being carried out to characterize the use of the test site by pelagic species (fish, plankton, etc.) compared to reference. Preliminary results show that jellyfish from a millimetre to centimetre size are dominant effects in the zooplankton pelagic community around the SEM-REV site in spring while millimetric crustaceans dominate in autumn.
 Completed
Habitat Change Invertebrates Fauna and flora composition (diversity, abundance and presence or absence of invasive species).
Image analysis (videos & photos taken during maintenance operations) and Systematic sampling (thickness, mass, volume, diversity). Completed for HYDROL44 (2015-2017), OMDYN & OMDYN2 (2015-2021), ABIOP (2017-2018), LEHERO MG (2017-2020), and MHM-EMR (2017-2020) projects.
The hub and the umbilical cable represent two different artificial habitats resulting in the presence of distinct species processions. Thus, the holes and cavities offered by the hub are largely colonized by conger eels (Conger conger) and European lobsters (Homarus gammarus). The Swell and the current generate sand movements around the umbilical cable that cause a Highly variable burial and sometimes depressions. These are all potential habitats for Dungeness crabs (Cancer pagurus) that burrow into it. An initial inspection by divers was carried out in the port area to ensure the absence of of non-native species prior to the installation of the FLOATGEN float at the offshore site. The monitoring carried out on site since the FLOATGEN installation has made it possible to qualify the species which have colonized the various submerged structures of the demonstrator, devoid of any Protection against biofouling. The predominant taxa are common mussels (Mytilus edulis), Hydrozoans (Amphisbetia operculata), Actinia (anemones: Metridium senile) and Alcyonids (soft corals: Alcyonium digitatum). A point of vigilance will also be paid to the evolution of the kelp (Laminaria sp.) population and Crepidula fornicata (Crepidula fornicata) on the float of FLOATGEN. The monitoring of the biocolonization of the structures of the SEM-REV and FLOATGEN test site will be continued throughout the experiment. In addition, data collected from 2018 to 2021 on this compartments still need to be analysed quantitatively.

 Completed
Changes in Flow Physical Environment, Sediment Transport Impact of anchors and electrical cables on the seabed. Study of the modification of the sediment nature by biocolonisation. Tracking in XYZ position (3D displacements) of the electrical cable. Geotechnical survey: bathymetry and side scan sonar, particle size, and total organic carbon analysis for the HOOPLA project (2016-2020), DYNA-REV project (2018) and SEMREVEDYS-2019 project (2019).
 Analysis of FLOATGEN's umbilical cable inspection and maintenance videos shows no sedimentary change at the point of contact between the cable and the bottom (Image A – FIGURE 38) in May 2019. Nevertheless, an aggregation of coarse particles (bivalve shells including a high proportion of common mussels Mytilus edulis) is observed on both sides of the cable over about 50 cm (Image B, C, D and E – FIGURE 38) as well as an elevation of the sediment over about 50 cm on both sides of the cable. As you move away from the contact point and get closer to the connection hub, the umbilical cable gradually becomes dirty until it is no longer visible on the bottom in January and May 2019. Underway since 2016
Changes in Flow Physical Environment Waves statistics model and weather prediction for marine operation and resource prediction. In-situ measurements of waves, currents and wind for the MOREDATAS project (2016-2019).
 Not yet publicly available. Underway since 2009