Abstract
Hundreds of different wave energy converter (WEC) concepts exist around the globe, yet none has individually reached a commercial stage. Various factors justify this, such as high costs and survivability at sea (short-term, due to storms, or long-term, due to fatigue and biofouling). Hence, a disruptive approach is required. This paper discusses a recently conducted experimental study of a hybrid system – triboelectric nanogenerators (TENGs) alongside E-Motions – aimed at efficient wave energy conversion under irregular wave action. While E-Motions is a novel roll-based resonant-type WEC, TENGs are a promising technology capable of efficiently converting low frequency, low amplitude mechanical motion into energy from any degree of freedom. Their combination ensures protection of all core electromechanical components, provides a dual energy conversion and retains the individual strengths of each system, such as adaptability to numerous floating structures, versatility and cost mitigation. Regarding the experiments, a half-cylinder shaped floater was constructed at a 1:20 scale to serve as the physical model floating platform. A TENG design was fabricated and introduced within the hull of the floater. The reproduced Power Take-Off (PTO), based on electromagnetic induction to mimic damping, served as the conversion system of E-Motions. It was found that the physical model denoted an overall strong hydrodynamic response over the considered range of irregular sea-states (eight, in total). This enabled a good energy conversion performance on the part of both E-Motions (maximum average power of 0.27 W, in model values) and TENGs (maximum average power of about 1.5 mW and power density up to 1.51 W/m2). The discrepancy between the power outputs should be perceived with caution, as the TENGs can be stacked in 3D layers, subjected to future enhancements and be directed towards powering of complementary systems with low energy demands, such as control systems and sensors.