Potential Energy Power from Tidal Current in Lagoon System – The Case of Oualidia Lagoon, Morocco

Abstract

The lagoon is a natural system protected from the sea by a dune barrier creating energy from the movement of rising and falling tides, thus providing a sustainable option for extracting energy from tidal currents. The energy that can be extracted is one of the most potential renewable energy sources. Therefore, the interaction of tidal currents with stratification layers has become important to optimize the efficiency of energy conversion at each depth layer in water masses. We have chosen as a case study, the Oualidia lagoon (Atlantic coast of Morocco). This ecosystem is characterized by hydrodynamics relatively favored by tides and tidal currents which are the main intra-lagoon currents, with a predominance of the semi-diurnal component M2 (period of 12 h 25) with 2.1 to 3.4m of tidal range. The Multicell Argonaut-XR ADCP is used to measure the current velocity in the Oualidia lagoon at three different stations to study tidal patterns in a vertical layer of water depth. At each station, current velocities were recorded in each 0.5 m layer over a depth of about 5 m. As a result, this study showed that current velocity measurements to be used as renewable energy are found at station 1 located at a depth of 3.5 meters (~layer 5) with a current velocity of 0. 771 m/s and a power density value of 235.344 Watt/m2, station 2 located at a depth of 3.5 meters (~layer 5) with a current velocity of 0.4 m/s and a power density value of 32.86 Watt/m2 and station 3 is located at a depth of 3 meters (~layer 6) with a current velocity of 0.527 m/s and a power density value of 75.157 Watt/m2. The variation in current velocities between the different stations is mainly influenced by tides (Flood/ebb), the period of the measurements and the location of the stations (far or near the lagoon inlets). This work presents a model for extracting electrical energy through the use of tidal and current flow variations in such semi-enclosed natural system including lagoons.