Estimated electricity production for an anti-roll tank deployed offshore for use as a wave energy converter

Abstract

Wave energy is the largest renewable energy resource; the total prospective annual wave energy resource offshore of Taiwan is approximately 16.9 TWh. To develop this energy potential, this study examines the anti-roll tank, which is used to reduce the excessive rolling of a ship, as a type of wave energy converter (WEC). From the perspective of energy interaction, the liquid in the tank absorbs part of the wave energy and converts it to a different type of kinetic energy during a ship's motion in the waves. Thus, for this study, a passive U-tube tank is chosen with a tank-carried buoy selected from a small craft. The liquid motion is coupled with the 5DOF equations of a ship's motion to calculate the frequency response functions (FRFs) of the tank's water height in regular waves, and then using the third-order Volterra model to construct the time histories of response at given seaway. The wave climate around Taiwan's coastal area is simulated using the Taiwan Coastal Ocean Modeling System (TaiCOMs) and the Longdong (25°05′43′′N, 121°55′21′′E), which is located in the northeastern coastal area of Taiwan, as a target testing area. Results show that the entire available electricity of 2009 was estimated to be approximately 7.2 × 10⁴ kWh per deployed buoy.

Keywords:

• passive U-tube tank
• wave energy converter
• the third-order Volterra model