Impacts of mechanical energy storage on power generation in wave energy converters for future integration with offshore wind turbine

Abstract

While offshore wind energy uptake is growing steadily, offshore wave energy remains largely untapped, despite having significant potential globally. The high cost and complexity of wave energy conversion systems are the main challenges to their commercial development globally, while they can be offset if they are integrated into the well-developed offshore structure of wind turbines. Since the source of the wave energy is associated with wind resources, these two ocean renewable resources have strong synergies that are yet to be combined effectively. Therefore, this paper aims to explore the idea of introducing wave energy converters into the offshore wind system as a hybrid system with a specific focus on wave energy converter (WEC) systems from their power characteristic perspective. In this paper, wave power fluctuations characteristics have been analysed and compared with wind power and two mechanical energy storage strategies, added inertia and gas accumulators, are investigated at the power take-off (PTO) system level on a typical point absorbed WEC. A sensitivity study of the impact of various mechanical storage systems on WEC performance was conducted under a set of real wave data. In addition, the significance of mechanical storage systems at the WEC PTO level in a DC-linked hybrid system is discussed along with enabling a better understanding of a future combined system. The results indicate that both mechanical storage options can effectively enhance energy production, reduce the power variations in the WEC system, and lead to the feasibility of integrating wave energy with the well-known offshore wind energy turbine system.