Tidal current power generation making use of a bridge pier

There are several advantages to make use of a bridge pier for the tidal power generation. Current velocity increases near the pier, therefore the tidal power generation becomes more efficient because the power is proportional to the cubic of the current velocity. The pier is convenient for access and maintenance of the hydraulic turbine and the power unit. The project is now underway at the Ikitsuki Bridge in Tatsuno-Seto Strait of Nagasaki Prefecture, where the tidal current was measured by the bottom mount ADCP for three months. The numerical simulations for the tidal current were conducted by the MEC Ocean Model, and the results were compared with the measurements. A long term estimation of the tidal current power is presented and the variation of the power by the lunar period is discussed. Model experiments for a Darrieus water turbine with three vertical blades were carried out in the water circulating channel, in which the power coefficients of the turbine are studied as a function of blade section and the mounting angle. Those experimental results are discussed to obtain an optimum Darrieus turbine for tidal power generation.