Pelamis Wave Power (United Kingdom)

The development of the Pelamis wave energy converter from its conceptual origins to its commercial deployment is reviewed. The early emphasis on designing for survivability and favourable power absorption characteristics focused attention towards a self-referenced articulated line-absorber in an attenuator orientation. A novel joint and control system allow the machine to be actively tuned to provide a resonant response power amplification in small and moderate seas. In severe seas, the machine is left in its default or natural condition, which is benign and non-resonant. Hydraulic rams at the joints provide the primary power take-off with medium-term storage in high-pressure accumulators yielding smooth electricity generation. Land-based modular construction requiring minimal weather windows for rapid offshore installation is an essential engineering feature necessary for viable commercialization. The second-generation Pelamis designs built for E.ON and ScottishPower Renewables are presented, and the scope for further cost reduction and performance enhancements are explained.

The design of a wave energy converter relies heavily on results from numerical simulations and experiments with scale models. Such results allow not only fun-damental design changes but also the optimisation of selected configurations. For ongoing development, and particularly at an early stage, numerical models give the flexibility of assessing a large number of versions at a relatively low cost. Physical models are then tested in wave tanks to validate the numerical simula-tions and to investigate phenomena which are not evidenced by the computational packages. This chapter provides an overview on the numerical techniques that have been used to model the hydrodynamics of wave energy converters (WECs), details on wavemaker and wave tank design, guidelines on experimental tech-niques and finally a case study related to one of the most studied concepts which reached the full-scale prototype stage.