This project has characterised and assessed the feasibility of an electric-hydraulic hybrid PTO. The project addresses one of the underpinning problems of wave energy: its fluctuating nature with a high peak-to-average load ratio. This concept also demonstrates a technology transfer of hydraulic hybrid power trains from the automotive to the wave energy sector.
The proposed solution is a combination of two main systems, an electric PTO and a hydraulic PTO. The electric PTO transforms energy in the most efficient manner, whilst the hydraulic system provides short term energy storage. In this way, the hybrid PTO can smooth incoming energy fluctuations without compromising the conversion efficiency.
This novel PTO system provides a higher efficiency compared with the conventional power chain and allows it to capture more energy. Also, the reduced peak to average energy ratio will benefit PTO survivability and reliability.