Challenges of using electroactive polymers in large scale wave energy converters

Electroactive polymers, or EAP, are a class of materials that change their shape when excited by an electric field. Main focus of research is currently the application of EAP as artificial muscles, where they convert electrical energy into motion. Conversely, they can also be used to convert mechanical energy into electrical energy. This paper describes the concept of a prototype wave energy converter, which is currently developed at SBM offshore in Monaco. The standing wave tube EAP wave energy converter is set to float under the ocean surface, where the system amplifies pressure waves similar to a travelling wave tube. No mechanical parts are used to convert the ocean waves into electrical energy; instead EAP is utilized to directly convert the pressure change into electricity. The whole system consists of EAP ring generators, which are distributed along a flexible, elastomeric tube. Since there are no rotating parts or pumps involved, no maintenance is required and the converter can run until failure to maximize return of investments. The flexible nature of the system poses unique challenges to the material design, especially since the system is supposed to be operated at field strengths above 50 V/μm in order to maximize the energy gained.