Proof of Concept of a Novel Hybrid Wind-Wave Energy Converter

Author(s):  
Carlos Perez-Collazo ◽  
Deborah Greaves ◽  
Gregorio Iglesias

In a global scenario of climate change and raising threats to the marine environment, a sustainable exploitation of offshore wind and wave energy resources is not only crucial for the consolidation of both industries, but also to provide a reliable and accessible source of renewable energy. In this context, and with the shared challenge for both industries to reduce costs, the combination of wind and wave technologies has emerged. In particular, this research deals with a novel hybrid system that integrates an oscillating water column, wave energy converter, with an offshore wind turbine substructure. In this paper, the novel hybrid wind-wave energy converter is studied in a three steps process. First, assessing a preliminary concept by means of a concept development methodology for hybrid wind-wave energy converters. Secondly, an OWC WEC sub-system is defined, on the basis of the results from the first step. Finally, the proof of concept of the WEC sub-system is carried out by means of a physical modelling test campaign at the University of Plymouth’s COAST laboratory.

2020 ◽  
Vol 162 ◽  
pp. 103731 ◽  
Author(s):  
Yu Zhou ◽  
Dezhi Ning ◽  
Wei Shi ◽  
Lars Johanning ◽  
Dongfang Liang

2020 ◽  
Vol 8 (3) ◽  
pp. 180 ◽  
Author(s):  
Sergej Antonello Sirigu ◽  
Mauro Bonfanti ◽  
Ermina Begovic ◽  
Carlo Bertorello ◽  
Panagiotis Dafnakis ◽  
...  

A proper design of the mooring systems for Wave Energy Converters (WECs) requires an accurate investigation of both operating and extreme wave conditions. A careful analysis of these systems is required to design a mooring configuration that ensures station keeping, reliability, maintainability, and low costs, without affecting the WEC dynamics. In this context, an experimental campaign on a 1:20 scaled prototype of the ISWEC (Inertial Sea Wave Energy Converter), focusing on the influence of the mooring layout on loads in extreme wave conditions, is presented and discussed. Two mooring configurations composed of multiple slack catenaries with sub-surface buoys, with or without clump-weights, have been designed and investigated experimentally. Tests in regular, irregular, and extreme waves for a moored model of the ISWEC device have been performed at the University of Naples Federico II. The aim is to identify a mooring solution that could guarantee both correct operation of the device and load carrying in extreme sea conditions. Pitch motion and loads in the rotational joint have been considered as indicators of the device hydrodynamic behavior and mooring configuration impact on the WEC.


Author(s):  
Antonis I. Vakis ◽  
Harmen Meijer ◽  
Wout A. Prins

A novel wave energy converter, termed the Ocean Grazer, designed to extract energy from waves of varying profiles and energy contents has recently been proposed by the University of Groningen. The authors have performed preliminary modeling work to predict the behavior of the converter’s power take-off system, and constructed a proof-of-concept prototype to validate basic model predictions.


2018 ◽  
Author(s):  
Caitlyn Clark ◽  
Bryony DuPont

Offshore wind and wave energy are co-located resources, and both the offshore wind and wave energy industries are driven to reduce costs while maintaining or increasing power production within developments. Due to the maturity of offshore wind technology and continued growth of both offshore floating wind and wave energy converter (WEC) technology, there is new opportunity within the offshore renewable energy sector to combine wind and wave technologies in the same leased ocean space through co-located array development. Combining wind and wave energy technologies through co-location is projected to have synergistic effects that reduce direct and indirect costs for developments. While several of these effects have been quantified, many have not been related to cost, and there is currently no cost model that incorporates all of these effects. Further, in areas where fixed-bottom offshore wind structures are infeasible, floating offshore wind platforms could provide access to plentiful resource further offshore. In this paper, we develop a cost model that represents co-located array developments, particularly for floating offshore wind and wave energy converter technology, and identify research gaps and uncertainties to be minimized in future work.


Author(s):  
Rony JS ◽  
Debabrata Karmakar

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.


2021 ◽  
Author(s):  
David M. Skene ◽  
Nataliia Sergiienko ◽  
Boyin Ding ◽  
Benjamin Cazzolato

Abstract The potential for coupling a cylindrical point absorber type wave energy converter (WEC) to a 5MW spar type floating offshore wind turbine is investigated. The wind and WEC system is modelled in the frequency domain and in two dimensions under the simplifying assumption that wind and waves propagate in the same direction. Coupling of the bodies is considered with respect to all theoretical combinations that might be achieved rather than a single specific design. Results are analysed with respect to the maximum power that the WEC coupling can achieve. It is shown that for mild waves the WEC can theoretically produce power in the range of 0.2 to 0.6 MW, its optimal dimensions are such that the draft and radius are approximately 18.8 m, and that obtaining this power tends to marginally amplify the pitch of the spar.


2005 ◽  
Vol 128 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Gaelle Duclos ◽  
Aurelien Babarit ◽  
Alain H. Clément

Considered as a source of renewable energy, wave is a resource featuring high variability at all time scales. Furthermore wave climate also changes significantly from place to place. Wave energy converters are very often tuned to suit the more frequent significant wave period at the project site. In this paper we show that optimizing the device necessitates accounting for all possible wave conditions weighted by their annual occurrence frequency, as generally given by the classical wave climate scatter diagrams. A generic and very simple wave energy converter is considered here. It is shown how the optimal parameters can be different considering whether all wave conditions are accounted for or not, whether the device is controlled or not, whether the productive motion is limited or not. We also show how they depend on the area where the device is to be deployed, by applying the same method to three sites with very different wave climate.


Author(s):  
Pedro C. Vicente ◽  
Anto´nio F. O. Falca˜o ◽  
Paulo A. P. Justino

Floating point absorbers devices are a large class of wave energy converters for deployment offshore, typically in water depths between 40 and 100m. As floating oil and gas platforms, the devices are subject to drift forces due to waves, currents and wind, and therefore have to be kept in place by a proper mooring system. Although similarities can be found between the energy converting systems and floating platforms, the mooring design requirements will have some important differences between them, one of them associated to the fact that, in the case of a wave energy converter, the mooring connections may significantly modify its energy absorption properties by interacting with its oscillations. It is therefore important to examine what might be the more suitable mooring design for wave energy devices, according to the converters specifications. When defining a mooring system for a device, several initial parameters have to be established, such as cable material and thickness, distance to the mooring point on the bottom, and which can influence the device performance in terms of motion, power output and survivability. Different parameters, for which acceptable intervals can be established, will represent different power absorptions, displacements from equilibrium position, load demands on the moorings and of course also different costs. The work presented here analyzes what might be, for wave energy converter floating point absorber, the optimal mooring configuration parameters, respecting certain pre-established acceptable intervals and using a time-domain model that takes into account the non-linearities introduced by the mooring system. Numerical results for the mooring forces demands and also motions and absorbed power, are presented for two different mooring configurations for a system consisting of a hemispherical buoy in regular waves and assuming a liner PTO.


Author(s):  
Eirini Katsidoniotaki ◽  
Edward Ransley ◽  
Scott Brown ◽  
Johannes Palm ◽  
Jens Engström ◽  
...  

Abstract Accurate modeling and prediction of extreme loads for survivability is of crucial importance if wave energy is to become commercially viable. The fundamental differences in scale and dynamics from traditional offshore structures, as well as the fact that wave energy has not converged around one or a few technologies, implies that it is still an open question how the extreme loads should be modeled. In recent years, several methods to model wave energy converters in extreme waves have been developed, but it is not yet clear how the different methods compare. The purpose of this work is the comparison of two widely used approaches when studying the response of a point-absorber wave energy converter in extreme waves, using the open-source CFD software OpenFOAM. The equivalent design-waves are generated both as equivalent regular waves and as focused waves defined using NewWave theory. Our results show that the different extreme wave modeling methods produce different dynamics and extreme forces acting on the system. It is concluded that for the investigation of point-absorber response in extreme wave conditions, the wave train dynamics and the motion history of the buoy are of high importance for the resulting buoy response and mooring forces.


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