Scavenging Energy from seA waveS with ElectroActive polymers – SEASEA

This multidisciplinary project is focused on the conversion of mechanical energy by using electroactive polymers to realize wave energy converters (WEC) in the improved performances.The consortium of four academic parteners was also supported by the SBM Offshore society, european leader on the market of WECs. SBM aims clearly at the second generation of WEC with improved performances: energy efficiency, reliability, integration to the environment.
Starting from the nano-object to end in a viable mechanical structure, the consortium tries to develop methods and processes which will be implemented in the future technologies of the energy and also aim at the realization of a functional prototype of laboratory.
The scientific approach includes:
- The development of quasi-industrial manufacturing processes of optimized active materials.
- Methods of optimization of creation and insertion of hybrid loads in a polymer matrix.
- Specifications for an industrial manufacturing process of eletroactive polymer films
- A methodology of design for optimized structures of conversion
- An analysis of the reliability and the failures of the structure accompanied with specifications for the realization of WECs of wide sizes.
- The realization of a functional prototype of laboratory constituting a module of an energy farm.

The main result relates to the realization of an industrial reliable manufacturing process for the development of conductive electrodes.

Another original result is the possibility to deposit electrodes by a spray method.

The discovery research with industrial vocation realized in the project SEASEA will lead eventually (> 15ans) to the development of offshore energy farms. In a closer future, the scientific and economic impact will be visible by:
- The control of technologies and knowledges (implementation of polymers, design of wave energy converters) transferable in the industry.
- The implementation of programs of collaborations between the partners of the project SEASEA and the industrial or institutional partners on projects more downstream.
- The possibility of generating some employment locally by the subcontractings associated with the project.

A poster was presented to EuroEAP conference in June 2016 at Copenhagen (Denmark). This conference was dedicated to last advances of electroactive polymers applications mainly in Europe but also in the world. We presented our results relating to the manufacture of original electrodes. Specific results on the change of electric properties when materials were subjected to mechanical stresses have completed this presentation.

The marine energies constitute a strategic sector of the renewable energies to diversify and complete the national energy mix. At present, France invests on technologies close to the industrial stage: offshore wind energy and the marine turbines. More upstream, still in the R&D phase, demonstrators of wave energy converters (WEC) based on a hydraulic conversion struggle to convince because of severe reliability issues. Wave energy generation could find a new impulse thanks to the development of breakthrough concepts based on innovative and economically favorable technologies: electroactive polymers (EAP). Based on the deformation of an EAP which both absorb the wave energy and converts it into electrical energy, these generators open interesting perspectives of development because they are freeof mechanical absorber which is at the origin of numerous failures of WEC devices. The company SBM Offshore bet on this breakthrough technology and presented in 2010 a world-first proof of concept of WEC on this principle. The challenge of the project SEASEA is to optimize these first converters by amplifying the conversion of clean energy and by making them more reliable. Among the identified challenges for the conception of second generation EAP-WECs, the availability of more performant materials to convert the mechanical energy is at the heart of the concerns. Starting from a nano-object to end in a viable mechanical structure, the consortium that is set-up (G2Elab, IMP, LaMCoS, MSSMAT, SBM Offshore) tries to develop methods and processes which will be implemented in the future technologies of the wave energy but also aims at the manufacture of a functional lab-scale prototype .
Our strategy is based on the incorporation of nano/micro hybrid reinforcements within a silicone matrix in order (i) to realize flexible conductive electrodes and (ii) to improve the properties of the active material. The so created composite has to maintain its elastic properties for the application: an optimization in the geometry of the nano/micro objects and their chemical nature as well as a work on the processing of mixture within the polymer matrix will be led. A strong aim is the manufacture of a monolith electrode-EAP-electrode using processes compatible with large-scale production (dynamic coater): pressing or gravitational casting. Thermodynamic modeling and experiments will complement each other to determine the structures-properties relationships of these composites to obtain an optimized material for the conversion of energy.
At the same time, hybrid structures which can associate several active materials will be developed to propose an innovating concept for the harnessing and the transformation of the energy. The distribution of the constraints within the structure of conversion, its damping and its coupling with the fluid environment will allow to maximize the recoverable energy but also to prevent any failure of mechanical or electrical origin. The mechanical and dielectric strength of the structures so realized will then be estimated from tests highlighting potential issues inherent to scale-up (patterning of the electrodes, self-healing…). A functional prototype will then be manufactured and tested. Its performances and the reliability of this new generation of generators will be assessed.
Because of the expected performances from materials and realized structures, the SEASEA project will concretize the entry of wave energy converters as an alternative or complementary approach to the current offshore devices with the clear advantage of reduced maintenance on site and lower ecological impact.