Under the topic of “hybrid structures using rotational moulding of polymers”, the partners in the RotoHybrid project will develop the materials and processing technology necessary to enable this versatile, lightweight polymer manufacturing process to be employed in the design of novel wave energy converters. Structure and prime mover CAPEX reductions of 50%-60% will be the long-term aim, with further OPEX reductions due to lower maintenance requirements and improved corrosion resistance in the ocean. The Stage 1 project will concentrate on an engineering design study to demonstrate the feasibility of constructing a full-scale WEC using rotationally-moulded polymer sections, with local metal and polymer composite structural reinforcement at loading/attachment points.

The aim is not to replace a large welded metal WEC structure (up to 20-25m in dimensions) with a single rotationally moulded polymer component, but rather to use a hybrid construction method, where reinforced rotomoulded sections can be brought together and assembled in a modular construction, using a steel skeleton, close to the site of the intended wave farm. This modular construction would enable large WEC devices to be transported internationally and assembled at a low cost, or alternatively manufactured near to site. The type of WEC hybrid construction being developed has the potential to offer a step-change in cost and design for future devices. Point absorbers and reacting heave plates would see the most benefit from this technology but it could also reduce the steel fraction in other WEC types such as attenuator rafts and oscillating wave surge converters.

Stage 1 will concentrate on demonstrating that significant reductions in LCOE can be targeted by re-design of an existing WEC using the rotational moulding process with selective  reinforcement, and using a hybrid steel skeleton for assembly.

Stages 2 and 3 will concentrate on test and demonstration and manufacturability. Stage 1 of RotoHybrid will include all of the partners necessary to manufacture and test a full-scale WEC in the new materials in Stages 2 and 3 of the project.