Tidal stream energy as a potential continuous power producer: A case study for West Japan

Abstract

Tidal current energy has two crucial advantages over other renewable sources: predictability and stability. These characteristics facilitate grid management, reduce energy storage costs and limit the usage of fossil fuel generators when available renewable energy resource does not fulfill electricity demand. This paper demonstrates the potential of tidal stream energy to provide stable and continuous power to the grid from farms at separated locations in West Japan due to the differences in phase of tidal harmonics. In this study, multiple combinations using five types of turbines at 17 potential tidal energy sites were evaluated based on current velocity results from an ocean circulation numerical model. More than 179,000 combinations (0.36% of all considered options) in which every turbine type is used for at least one tidal site were analyzed. Results show that a firm capacity of 2.61% of total installed capacity can be reached, with relatively high global time-averaged capacity factors (> 0.34) and low coefficients of variance (< 0.56) for the 3-month simulation period. In each of these cases, monthly fluctuation was found lower than 2.6%, negligible when compared to solar or wind energy. From these results, it was concluded that, despite the need for strategic planning, tidal stream energy can provide continuous power production with acceptable values for capacity factor and coefficient of variance under multiple site-turbine type combinations, leaving a wide margin for free market.