EDF Paimpol-Brehat tidal current turbine farm: first achievement and preparation for grid connection

EDF has decided in 2007 to test a new technology in order to produce electricity from tidal currents, which have the particular interest of being predictable and environmental friendly during installation and operation. The main goal of EDF was to test a farm of several turbines (rated 0.5 MW at 2.5 m/s) connected on the distribution network, through an offshore sub-sea converter and an onshore substation linked with a single 16 km long submarine cable. Such power technology is predictable and has low impact on its environment, during installation or operation phases. The innovative aspect of this project is the design and implementation, for the first time, of a farm architecture in order to prepare the next step with tidal arrays of several dozens of turbines. The chosen site is the Horaine location, near Brehat Island. EDF decided in 2008 to select OpenHydro, an Irish energy company as the technology partner for implementation of the tidal array. Their open-center turbine is integrated in a venturi and installed on a tripod simply laid on the seabed. The synchronous generator is composed of permanent magnets. The paper presents the Paimpol-Brehat project development with the technology selection, the technical developments, and particularly the specific submarine connection system. Concerning this last topic, the paper will present the general concepts in terms of connection architecture for several turbines, taking into account the constraints of submarine systems and marine operations. (authors)