Robust point wave energy device with smooth output

Completed

Renewable Energy Sources(Ocean Energy)

Basic and strategic applied research

ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering)

Not Cross-cutting

Professor PK Stansby
Mechanical, Aerospace and Civil Engineering
University of Manchester

3

Carbon Trust

01 January 2004

30 December 2004

12 months

£39,770

North West

Professor PK Stansby, Mechanical, Aerospace and Civil Engineering, University of Manchester

This project will provide proof of concept for a particular robust point absorber, which specifically provides smooth output. In this design the inertia of the rotating components will be sufficient to permit a smooth continuous power output over cycles of wave action. The aim of this project is to produce a mathematical model and identify critical parameters, for application to offshore sites. The experimental investigation in parallel will be undertaken in a laboratory wave flume to minimisecosts.

Offshore wave energy has the potential for supplying a significant proportion of the UK's total energy requirement. In such a hostile environment, the components of an extraction device in contact with water should be as robust and simple as possible. This device uses a slightly buoyant body connected by a cable to a free-wheel sited on a platform, which may be a large floating structure in deep water or a structure supported from the sea bed in shallow water. The free-wheel is based on established technology and may be set up to supply constant electrical power. The buoyancy of the body may be adjusted to produce resonance in low sea states (swell) where amplification of motion is most needed. A device with a typical body dimension of 10m would supply about 0.3MW in waves of 2m height and 10s period. The device is ideally suited to multiple deployment, with, say, 100 giving 30MW in such low sea states. In extreme sea states the body may be lowered well below the water surfaceto avoid extreme loading. In this initial project the shape of the body will be optimised for hydrodynamic efficiency using small-scale laboratory flume tests and a mathematical/ numerical model will be developed for general application in offshore conditions. Follow-on projects will investigate the device in a large flume giving about 1m wave heights and at a coastal/offshore site. The ultimate goal is that multiple deployment of such devices in an offshore wave energy farm, supported on a massive, probably concrete, floating structure, will be able to generate about 30MW in calm conditions or over 100MW in moderate sea states

01/01/07