Gain in production per pump

If we pump for 1 or 1.5 h when the basin level is close to sea level, we significantly increase overall production, as we increase the volume to be turbined and the average head over the following 4 or 5 h. To this end, large-diameter bulbous units of the order of 20 MW can be installed in the dike, capable of pumping 1,500 h/year (while avoiding pumping during peak current demand). These units are also capable of turbining, but their turbining capacity is lower than their pumping capacity.

As well as being cost-effective, this additional investment has the advantage of enabling the exact amplitude of natural tides to be maintained at the coast, thus avoiding the corresponding criticism of the environment.