STC (Spar-Torus Combination): A Combined Spar-Type Floating Wind Turbine and Large Point Absorber Floating Wave Energy Converter — Promising and Challenging

2012 ◽  
Author(s):  
Made Jaya Muliawan ◽  
Madjid Karimirad ◽  
Torgeir Moan ◽  
Zhen Gao
Keyword(s):  
Wind Turbine ◽  
Wave Energy ◽  
Capital Investment ◽  
Technical Information ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Point Absorber ◽  
Floating Wind Turbine ◽  
Readiness Level ◽  
Novel Concept

This paper deals with a novel concept by combining a spar-type floating wind turbine (FWT) and a Torus (donutshaped) point absorber-type wave energy converter (WEC) that is referred as the ‘Spar-Torus Combination’ (STC) herein. Concept feasibility study has been carried out by doing numerical simulations. It showed that the STC results in a positive synergy between wind and wave energy generation in terms of both capital investment and power production. As a novel concept, the STC concept is considered a simple compact combination of two technologies that have had high technology readiness level (TRL). It is suitable for deep water deployment and is not sensitive to seabed conditions and wave directions. Therefore, it is interesting to pursue a further development of this concept. The paper presents the technical information about the STC and highlights some challenging areas of the STC that should be carefully looked at to make it a proven concept.

Dynamic Response of a Combined Mono-Pile Wind Turbine and Heave-Type Wave Energy Converter System

2017 ◽  
Author(s):  
Nianxin Ren ◽  
Ying Zhu ◽  
Zhe Ma ◽  
Wei Li
Keyword(s):  
Wind Turbine ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Wave Loads ◽  
Energy Converter ◽  
Type Wave ◽  
Loads Analysis ◽  
The Time Domain ◽  
Novel Concept ◽  
Multi Body

In present work, a novel concept by combing a monopile wind turbine and a heave-type wave energy converter has been proposed, that is referred as the ‘MWWC’ (Mono-WT-WEC Combination) system herein. Concept feasibility study has been carried out by doing coupled aerodynamic and hydrodynamic numerical simulation in the time domain. Aerodynamic loads and output wind power of the NREL 5MW wind turbine are determined by the NREL Aerodyn code, based on BEM method. Hydrodynamic loads of the mono-pile and the WEC are calculated by the AQWA code, which is available for modeling multi-body systems including both mechanical and hydrodynamic couplings between the mono-pile and the WEC. Firstly, the effect of different power-take-off (PTO) parameters and wave periods on the performance of the WEC’s wave energy production under typical wave cases has been investigate, and a preliminary optimal value for the PTO’s damping stiffness has been proposed; secondly, the dynamic characteristic of the MWWC system has been investigate using coupled wind-wave loads analysis under typical operational sea cases. Finally, the extreme responses of the MWWC system have been obtained for its ULS design, and the potential challenging areas of the MWWC system has been highlighted.

Coupled dynamic analysis of hybrid offshore wind turbine and wave energy converter

2021 ◽  
pp. 1-40
Author(s):  
Rony JS ◽  
Debabrata Karmakar
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Offshore Wind ◽  
Irregular Waves ◽  
Energy Converter ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Energy Converters

Abstract The combined offshore wind and wave energy on an integrated platform is an economical solution for the offshore energy industry as they share the infrastructure and ocean space. The study presents the dynamic analysis of the Submerged Tension-Leg Platform (STLP) combined with a heaving-type point absorber wave energy converter (WEC). The feasibility study of the hybrid concept is performed using the aero-servo-hydro-elastic simulation tool FAST. The study analyses the responses of the combined system to understand the influence of the WECs on the STLP platform for various operating conditions of the wind turbine under regular and irregular waves. A positive synergy is observed between the platform and the WECs, and the study also focuses on the forces and moments developed at the interface of the tower and platform to understand the effect of wind energy on the turbine tower and importance of motion amplitudes on the performance of the combined platform system. The mean and standard deviation for the translation and rotational motions of combined wind and wave energy converters are determined for different sea states under both regular and irregular waves to analyse the change in responses of the structure. The study observed a reduction in motion amplitudes of the hybrid floating system with the addition of the wave energy converters around the STLP floater to improve the energy efficiency of the hybrid system. The study helps in understanding the best possible arrangement of point absorber type wave energy converters at the conceptual stage of the design process.

scholarly journals Passive Model Predictive Control on a Two-Body Self-Referenced Point Absorber Wave Energy Converter

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1731
Author(s):  
Dan Montoya ◽  
Elisabetta Tedeschi ◽  
Luca Castellini ◽  
Tiago Martins
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Wave Energy ◽  
Power Flow ◽  
Linear Constraints ◽  
Wave Energy Converter ◽  
Control Technique ◽  
Computational Time ◽  
Energy Converter ◽  
Point Absorber

Wave energy is nowadays one of the most promising renewable energy sources; however, wave energy technology has not reached the fully-commercial stage, yet. One key aspect to achieve this goal is to identify an effective control strategy for each selected Wave Energy Converter (WEC), in order to extract the maximum energy from the waves, while respecting the physical constraints of the device. Model Predictive Control (MPC) can inherently satisfy these requirements. Generally, MPC is formulated as a quadratic programming problem with linear constraints (e.g., on position, speed and Power Take-Off (PTO) force). Since, in the most general case, this control technique requires bidirectional power flow between the PTO system and the grid, it has similar characteristics as reactive control. This means that, under some operating conditions, the energy losses may be equivalent, or even larger, than the energy yielded. As many WECs are designed to only allow unidirectional power flow, it is necessary to set nonlinear constraints. This makes the optimization problem significantly more expensive in terms of computational time. This work proposes two MPC control strategies applied to a two-body point absorber that address this issue from two different perspectives: (a) adapting the MPC formulation to passive loading strategy; and (b) adapting linear constraints in the MPC in order to only allow an unidirectional power flow. The results show that the two alternative proposals have similar performance in terms of computational time compared to the regular MPC and obtain considerably more power than the linear passive control, thus proving to be a good option for unidirectional PTO systems.

High-performance and robust bistable point absorber wave energy converter

2021 ◽  
pp. 108767
Author(s):  
Ru Xi ◽  
Haicheng Zhang ◽  
DaolinXu ◽  
Huai Zhao ◽  
Ramnarayan Mondal
Keyword(s):  
Wave Energy ◽  
High Performance ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Point Absorber
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