Innovative tidal turbine with central deflector for the exploitation of river and sea currents in on-shore installations

The paper presents an innovative system for the collection of energy from river and tidal currents, designed with the objective of combining high performance, cost-efficiency and simplicity. The proposed system consists of a kinetic turbine able to be immersed inside water currents and kept in equilibrium by the action of a central deflector and a steel cable anchored to the shore. The size and the orientation of the deflector are defined according to the working conditions and desired equilibrium position. The paper also describes the design parameters of a demonstrative installation at Punta Pezzo (Villa San Giovanni, Italy), located in the Strait of Messina. In the selected site, nearby the coast, the peak current speed reaches 3 m/s (6 kn). The turbine and its components have been designed assuming that the machine will always work under maximum power coefficient conditions. This implies a variable rotational speed, so the use of an inverter becomes mandatory. Preliminary performance estimations show that the system can provide electrical power of about 470 kW, with 43% efficiency when the system works under optimal conditions.