Experimental Testing of Dielectric Elastomer Generators for Wave Energy Converters

Dielectric elastomer generators (DEGs) are high-voltage electrostatic transducers made of lightweight low-cost compliant polymeric materials. In the last few years, DEGs have been regarded as an interesting technology for wave energy converters (WECs). In particular, it has been suggested that DEGs may be promisingly employed as the power take off (PTO) in oscillating water column (OWC) and pressure differential (PD) systems. This paper presents a survey of the experimental results that were obtained in the last four years and that are currently in progress on a specific DEG PTO solution. Such a DEG consists of a circular diaphragm of elastomeric material, which can be deformed by the pressure variation in a closed air chamber of an OWC or by the direct pressure induced by water in PD devices. Two classes of experiments are described in the paper: dry-run laboratory tests on DEG samples, and wave-tank tests on scaled OWC prototypes that include functional DEG PTOs able to generate electrical power out of the energy of small scale waves.