Synergistic integration of water wave concentration and pendular TENGs for boosted blue energy conversion

Energy transition is one of the great challenges of our era and its resolution requires a diversified approach in which the oceans play a pivotal role. The recent discovery of the triboelectric nanogenerator (TENG) opened a novel path towards highly efficient low-frequency mechanical energy harvesting from a variety of sources, including ocean waves. Previous demonstrations of blue energy TENGs have shown that wave regimes of high amplitude are advantageous and produce significantly higher power outputs, but none have explored whether these can be mimicked by external wave manipulation. This work aims to understand if the synergistic integration of water wave concentrating systems and wave energy harvesting TENGs is possible. First, a simple system composed of a straight reflector and a round depth-based concentrator was proven to be effective at enhancing wave amplitude as much as 125% by a computational fluid dynamics simulation and experimental tests within a small wave tank. Then, a pendular contact-separation TENG was developed and tested in both dry-bench and wave tank experiments, revealing that its performance is enhanced for high amplitude motions, and that this can be mirrored by a concentrated wave regime. The addition of the round concentrator at the ideal distance from the reflector produced an increase of 147% in wave amplitude, which was responsible for an increase of 116% in the average output voltage. These results demonstrate that the manipulation of water waves could provide an effective strategy to externally improve the output of blue energy harvesting TENGs.