Paimpol-Bréhat: Development of the First Tidal Current Array in France
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3rd International Conference on Ocean Energy, 6 October, Bilbao Paimpol-Bréhat: Development of the First Tidal Current Array in France P. Brun 1, L. Terme 2 and A. Barillier 3 1Hydro engineering centre Electricité de France Savoie Technolac 73 373 Le Bourget-du-Lac Cedex E-mail : [email protected] 2Hydro engineering centre Electricité de France Savoie Technolac 73 373 Le Bourget-du-Lac Cedex E-mail : [email protected] 3Hydro engineering centre Electricité de France Savoie Technolac 73 373 Le Bourget-du-Lac Cedex E-mail : [email protected] Abstract 1. Introduction In order to launch the development of tidal current energy in French waters, EDF has decided to This paper presents the stages of development of EDF develop a pilot farm of TCEC (Tidal Current first tidal current project in French waters; the Paimpol- Energy Converters) by 2012. The main purpose of Bréhat project. The objectives and key features of the this project is to set up an overall framework for the project are first described. implementation and operation of such marine The process for site selection is explained. renewable energy production site. The technology selection is explained and a brief EDF decided in 2008 to develop the site of Paimpol- presentation of OpenHydro’s technology is provided. Bréhat in North Brittany and selected The surveys undertaken for the Paimpol-Bréhat project OpenHydroGroup Ltd., an Irish energy company as are presented together with key findings. the technology partner for implementation of the The final tidal array layout is presented taking into tidal array. account all the constraints identified. The Paimpol-Bréhat project consists of a The grid connection architecture and characteristics are configuration of 4 machines with 0,5 MW capacity described. per unit for 2,5 m.s -1 (0,85 MW peak capacity per Details regarding EIA and including the challenges of unit), an offshore subsea converter, a 15km 10kV the administrative procedures are given. DC transmission line for grid connection and an on shore substation. The implementation schedule is shown and the critical The major specificity of the project is its path identified. environmentally friendly characteristics. The paper presents the Paimpol-Bréhat project This paper does not present the economic aspects of the development focusing on the site and technology project; which is considered to be a pre-industrial selection, the consent, the field investigation and demonstration. surveys, the technical studies (including R&D 2. Objectives and main characteristics of the developments and environmental impact project assessment) and the administrative authorization In order to launch the development of tidal current process. energy in French waters and to assist in meeting the The design is described and in particular the 2020 target for renewable energy, EDF has decided to technical options selected are explained taking into construct a demonstration tidal farm by 2012. account environmental context, consent by The main purpose of this project is to set up an overall stakeholders, technical and administrative context. framework for the implementation and operation of a Keywords: OpendHydro, Paimpol-Bréhat, Tidal current demonstration tidal farm to include: array. • Full-scale test of a TCEC array, 1 3rd International Conference on Ocean Energy, 6 October, Bilbao • Validation of EDF modelling tools including OpenHydro Group Ltd. is an Irish company whose wake effect and energy yield calculations, business is the design and manufacture of the Open- • Environmental Impact Assessment and Centre Turbine. This unique and simple device is Environmental Monitoring Program, designed to extract marine renewable energy from tidal • Optimisation of offshore installation process, streams in a simple and environmentally benign Development of consent process with all manner. The machine has a single moving part and is stakeholders, situated directly on the seabed, with no part of the • Development of administration, legal and structure visible from the surface and deep enough so taxation framework. as not to pose a hazard to shipping. OpenHydro deployed their first 6m tidal turbine in 3. Site selection and consent by stakeholders 2006 at the European Marine Energy Centre (EMEC) EDF R&D and Hydro Engineering have already carried in Orkney, Scotland. OpenHydro installed a 10m out several surveys and feasibility studies on the turbine in the Bay of Fundy in Nova Scotia, Canada viability of tidal energy in French waters together with last November 2009. upfront dialogue with all the stakeholders. Through The Paimpol-Bréhat project involving OpenHydro these studies, two sites were shortlisted, the first technology requires extensive research and located in Northern Brittany and the second in development prior to the finalization of the project Normandy (Cotentin). design, construction and commissioning. The following development is necessary due to the site conditions and EDF decided in July 2008 to develop the Northern the decisions made by EDF: increase the installed Brittany site, which is located off Bréhat Island, mainly capacity of each machine (and therefore the size of for acceptability and consent reasons in addition to the turbine to 12 m and venturi to 16m), adapt the favourable grant support structures available in geometry of the turbine and characteristics of the Brittany. subsea base. The key features of the 16m machines are as follows: • Turbine weight 100t, Barfleur • Subsea base weight 490t, • Subsea base dimensions 21x23m. A number of technical studies have currently been Paimpol-Bréhat performed for the development of the larger 16m turbine focusing the improvement of efficiency for blades and venturi and for generator and mechanical parts. To allow the engineering teams to trial their designs and also for the project to mitigate the risk it is planned to install a machine in spring 2011, not connected to the grid; one year before the commissioning of the full Figure 1 : Location of PAIMPOL-BREHAT project demonstration tidal farm (4 turbines). The strong acceptance that the project currently receives was achieved primarily due to permanent consultation with key stakeholders and this consultation was undertaken at a very early stage of the project. The main stakeholder is the local committee of fishermen; all discussions between this committee and EDF were decisive regarding the location of the machines (layout, depth) and the cable route and protection. The requests of all other stakeholders (oyster farm owners, authorities in charge of environment, environmental associations, riparian and municipality) were also considered and taken into account to adapt the project design. 4. Technology selection After a multi criteria analysis (economical, financial, Figure 2 : 10m OPENHYDRO machine view CAD technical, feedback of first prototypes, willingness to collaborate) and a pre-qualification process, EDF Tidal energy has a number of important benefits selected OpenHydro as the technology partner for including predictability of energy generation but also it implementation of the tidal array. This selection was is seen as having minimal impacts both made among 5 short-listed developers: OpenHydro, environmentally and socio-economically. It is Marine Current Turbines (MCT), Hammerfest Storm, important for this specific project to demonstrate these Tidal Generation and Lunar Energy. characteristics: 2 3rd International Conference on Ocean Energy, 6 October, Bilbao • the tidal array has no significant negative impact on socio-economic activities due to it being located in a fishing reserved area, as agreed with fishermen; Parc hydrolien • each turbine is supported on a tripod subsea base foundation directly deployed on the seabed, which limits the area of contact and does not N require any seabed preparation; • the turbine has no requirement for oils or lubricants; • the turbine has a large open centre which Figure 4 : Geological map provides an exit route for marine life. The results of the marine investigations can confirm the feasibility of machine installation and allow the cable 5. Surveys to be buried on the stretch close to the shore (it will lay EDF completed a number of field investigation and on the seabed on the rest of the route). It is surveys as part of the feasibility studies from 2005 to demonstrated that the level of impact of the project on 2008. Further survey work was completed in early the environment is low and can be mitigated. 2009. These investigations are listed as follows: • Tidal velocity measurements using Acoustic 6. Layout Doppler Current Profilers (ADCP), The layout of the tidal farm has been one of the most • Bathymetry and Geophysics (magnetometer, challenging aspects of the project to date; the crucial seismic refraction, material sampling), question was the following: how to design the optimum • Environmental surveys, machine position taking into account: • Inspection by divers, • Current velocities (magnitude and direction), • Geotechnics: boreholes at the onshore site. • Minimization of the wake effect, • Optimisation of the output generation, The marine investigations provide a good knowledge of • Navigation constraints and in particular the physical characteristics of the project area: fishermen ships’ draught, • Depth at the deployment area is between –35m • Micro relief and angular tolerance (rolling and and –40m (from chart datum), pitching), • The deployment area is generally flat but the • Accuracy for machine installation on the