Despite the considerable efforts the international research community has made over the last decades, wave energy technologies have failed to achieve the desired design convergence to support their future market growth. Many technical challenges remain unresolved, leading to high costs of energy in comparison with other renewable energy sources. It becomes apparent that incremental innovation alone cannot fill the gap between the current techno-economic estimates and the medium-term policy targets established for wave energy.
A systematic problem-solving approach must be embedded from the outset of technology development to meet the high sector expectations. This approach should support the engineering design processes, facilitate traceability of engineering analysis, and provide practical tools for understanding the wave energy context, formalising wave energy system requirements, guiding techno-economic design decisions, and overcoming technical challenges.
Systems Engineering methods have been successfully applied to developing complex commercial products in many sectors. Among the many tools developed in Systems Engineering, it is worthwhile mentioning two structured innovation techniques: Quality Function Deployment (QFD) for problem formulation and selection ; and the Theory of Inventive Problem Solving (TRIZ) for concept generation . Unfortunately, their use in wave energy is still limited and fragmented.
Taking as a starting point the technology-agnostic assessment of wave energy capabilities performed in previous research work  for the problem formulation and concept selection, the authors have applied QFD to obtain the prioritisation of the technical characteristics that may offer the greatest impact to the overall design for a wave energy system. The main Functional Requirements are mapped to an equal number of Design Parameters extracted from the 39 technical parameters provided by TRIZ. The TRIZ toolkit is then employed to suggest three alternative innovation strategies to overcome wave energy cost and performance limitations.
Firstly, separation principles are used to deal with physical contradictions. Examples of potentially effective strategies involving separation in time, space, scale or condition are proposed.
Subsequently, inventive principles are employed to solve technical contradictions and trade-offs. The four most promising inventive principles that have been found in this implementation are "Local quality", "Dynamism", "Pneumatics or hydraulics", and "Physical or chemical properties". These principles prompt the user to consider a broader range of alternatives and improve creative thinking. Additional examples are given on how these inventive principles could be applied in wave energy.
Finally, a system transition strategy is needed for the most complex challenges. Bypassing contradictory demands involves more radical changes in the functional allocation of requirements to the physical embodiment. Therefore, such a significant pivot in wave energy design can only be made in the initial phases of technology development.