Session: 09-01-13 Novel and Hybrid Offshore Wind Concepts

Paper Number: 79483

79483 - Power Performance and Response Analysis of a Semi-Submersible Wind Turbine With Combined Flap Type and Torus Wave Energy Converters 

An integrated offshore wind and wave energy system is an attractive concept in areas with abundant wind and wave energy resources. The sharing of supporting platform and facilities, e.g. mooring systems, offers significant cost savings. This will effectively lower the levelized cost of energy (LCOE). In the present study, a conceptual design consists of a braceless semi-submersible floating horizontal axis wind turbine (FHAWT), three flap-type wave energy converters (WECs) as well as a torus (donut-shaped) point absorber-type WEC is proposed. The flap-type WECs harvest wave energy through the flap motion caused by oscillating wave surge while the torus WEC absorbs wave energy generated from its heaving motion relative to the platform. The absorbed mechanical power of the power take-off (PTO) systems is calculated based on linear damping forces and the relative motions of the WECs. Hydrodynamic couplings between the WECs and the platform are taken into account using springs and dampers. A fully coupled aero-servo-hydro-elastic numerical model of the concept is constructed. The feasibility study of the concept is carried out using time domain simulations. Both operational and 50-year extreme environmental conditions are simulated based on simultaneous wind and wave hindcast data of the selected offshore site. The effect of the WECs on the total power take-off, platform motions and structural loads in the turbine tower, WEC supporting structure and mooring lines are examined. The annual energy production (AEP) is estimated and discussed.

Presenting Author: Chern Fong Lee University of Stavanger

Authors:

Chern Fong Lee University of Stavanger
Christodoulos Tryfonidis University of Stavanger
Muk Chen Ong University of Stavanger