Flowatt tidal turbine farm

Analysis of extreme sea conditions in the Raz Blanchard

Located at the north-western edge of Normandy (France), the Raz Blanchard is a cape where tidal currents are extremely powerful, making it a unique energy site for the installation of tidal turbines.

Artelia has been studying the site for several years and is now providing its knowledge of the site’s marine conditions to the company HydroQuest, which plans to create a tidal turbine farm of 7 machines (Flowatt project) developing 17.5 MW, the first of its kind in the world.


Whether installed on the seabed or floating, tidal turbines generate renewable electricity from the force of ocean currents. These technologies offer a number of advantages. Firstly, this source of energy is totally predictable and reliable, since it is based on the dates and times of the tides. This predictability is a real asset for supporting electricity grids by creating a reliable and anticipated production base. What’s More, the time between tides is short enough to ensure that, if tidal turbines are linked to an electricity storage solution, constant production can be supplied to the grid. Tidal turbines are also a way of producing electricity that has an extremely limited impact on the marine environment and biodiversity.

There are seven sites in France where tidal turbines can be installed to produce low-carbon, renewable energy (total potential estimated at 4 GW). The Raz Blanchard site, one of the most promising, has already attracted a number of developers that Artelia has worked with over the years. Today, alongside HydroQuest, a tidal turbine developer with whom they have already worked for river applications in particular, our teams are analysing the ocean conditions in the area where the future Flowatt farm will be located and the corridor along which it will be connected to land. Artelia is providing its expertise in assessing extreme conditions using extrapolation methods for different timeframes for the various parameters, whether combined or not, such as swell, water levels and currents. These methodologies are state-of-the-art and have been the subject of several presentations at conferences and publications in peer-reviewed journals, and were initially presented and justified in a doctoral thesis.

The Flowat project represents an important step forward, as it proposes to progress from a demonstrator to an industrial and commercial development phase. It comprises 7 2.5 MW machines that will be installed 3 km off the coast at a depth of 35 m. Harmless to wildlife, these OceanQuest tidal turbines, more than 10 m high and 200 tonnes in weight, will supply the equivalent of 20,000 people with renewable, predictable energy at a cost that HydroQuest claims to be very competitive.