Comparison Of a Floating and a Bottom Fixed Tidal Turbine in a Coastal Marine Environment

The predictability and opportunity to provide baseload power has made tidal energy one of the most attractive marine renewable energy resources to help fight anthropogenic climate change. This has led to extensive research regarding the overall resource and methods of extraction. However, with differing designs found in today’s tidal turbine market, it is clear that there remains an ongoing debate as to where a tidal turbine should sit within the water column. In this study, a floating turbine and bottom mounted turbine, both based on current designs found in the market, were analysed over a tidal cycle in a 3D hydrodynamic model of the Morlais tidal test zone. The model was validated from ADCP measurements from the same area and recorded over the same tidal cycle. The aim was to establish the most efficient design and its effect on the surrounding water column. The results showed significant differences in the near-field effects of each turbine, but negligible effects were found further afield. Over the established tidal cycle, the floating turbine was found to be more efficient.