Wave devices typically comprise one or more floating bodies whose oscillation drives an electric generator. Recent estimates suggest that more than 12% of UK electricity demand could be generated from such devices deployed around the UK.
To realize this potential, commercial-scale projects are expected to comprise large numbers of individual devices deployed in arrays, typically in water depths of 50 m and greater. Devices must be designed to generate electricity from average wave heights of around 1-2 m but must also resist damage during extremely severe individual waves that are an order of magnitude larger.
At present a handful of such systems are undergoing prototype trials at offshore test centres such as the European Marine Energy Centre (EMEC).
- Influence of hydrodynamic interactions on response and energy yield of devices in arrays.
- Wave field modificiation due to energy extraction
- Response and loading of devices due to extremely severe waves
- Evaluation of device concepts
Manchester has conducted detailed experimental studies of response of individual devices to extreme waves and interactions amongst arrays of devices.
Numerical methods employed range from linear wave theory (often by the commercial code WAMIT) through to Smooth Particle Hydrodynamics (SPH) which has been developed to simulate floating body response to focused waves.
The M4 Wave Power device is a Moored Multi-body Multi-Mode system with three floats providing high wave energy capture, defined in terms of the width of the energy transmitted across a wave crest defined in terms of wavelength. The theoretical maximum capture width is about 75% of a wavelength and experimental magnitudes in irregular, directionally spread waves are 25-40% of a wavelength defined by the energy period. Further information
Methods for assessing economic viability of large scale marine energy projects were developed as part of the EU FP7 Equimar project.
The group recently contributed to the EU FP7 WECwakes project involving experimental study of wave-field changes in the vicinity of a wave energy converter (WEC) array.
Prof Peter Stansby currently leads the EPSRC marine energy challenge project STEP-WEC concerning novel concept development and evaluation.