First Steps in the Design and Construction of the Ocean Grazer

2014 ◽  
Author(s):  
Antonis I. Vakis ◽  
Harmen Meijer ◽  
Wout A. Prins
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Proof Of Concept ◽  
Energy Converter ◽  
Basic Model ◽  
Model Predictions ◽  
The University ◽  
Design And Construction

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.

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

2018 ◽  
Author(s):  
Carlos Perez-Collazo ◽  
Deborah Greaves ◽  
Gregorio Iglesias
Keyword(s):  
Wave Energy ◽  
Wind Wave ◽  
Physical Modelling ◽  
Wave Energy Converter ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Proof Of Concept ◽  
Energy Converter ◽  
Wave Energy Converters ◽  
The University

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.

Development of a Model Predictive Controller for the Wave Energy Converter Control Competition

2019 ◽  
Author(s):  
Bradley A. Ling
Keyword(s):  
Prediction Model ◽  
Wave Energy ◽  
Linear Prediction ◽  
State Space Model ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
Point Absorber ◽  
Predictive Controller ◽  
Excitation Force ◽  
The University

Abstract The University of Maynooth is hosting a competition to develop a control strategy for a heaving point absorber wave energy converter (WEC). A linear model predictive control (MPC) design for the competition is presented. The state space model used in the MPC was derived numerically from the provided WEC-Sim model using linear system identification methods. A Kalman filter was used as the estimator, while also serving as an unknown input estimator to provide estimates of the excitation force on the WEC. The required excitation force predictions were made using an autoregressive linear prediction model. The inputs to the prediction model included estimated wave excitation forces and measured water surface elevation values from an up-field wave probe. Simulation results of the final control system design are also presented for each of the six wave cases specified by the competition organizers.

scholarly journals Responsiveness comparison between a lift-type and drag-type rotor in waves

2018 ◽  
Vol 57 ◽  
pp. 02001
Author(s):  
Yingchen Yang ◽  
Fredrick Jenet ◽  
Deyanira Jimenez ◽  
Brandon Benavides ◽  
Jesus Cerda ◽  
...  
Keyword(s):  
Wave Energy ◽  
Recent Progress ◽  
Vertical Axis ◽  
Frequency Discrimination ◽  
Wave Energy Converter ◽  
Experimental Results ◽  
Proof Of Concept ◽  
Energy Converter ◽  
Common Features ◽  
Research Findings

Our recent progress on development of a vertical-axis unidirectional rotary wave energy converter (WEC) is discussed in this work. The WEC features a vertical-axis rotor that preforms unidirectional rotation in waves. The vertical axis arrangement makes the WEC respond well to waves from any direction with no realignment needs. And, the unidirectional behavior of the rotor promises no wave-frequency discrimination, which is in comparison to reciprocating WECs that employ the resonant principle and are very frequency-specific. In our earlier proof-of-concept studies, we have successfully demonstrated two types of rotor designs: a lift type employing hydrofoil blades and a drag type using cup blades. In the present work, the two rotor types were further explored experimentally by employing more rotor configurations and blade shapes. The focus was on revealing the rotor responsiveness in simulated waves under a freewheeling condition. The experimental results were compared between a lift-type and drag-type rotor. The comparison provided in-depth understanding on common features of the two rotor types and major differences between them. The yielded research findings will directly guide the development of a prototype vertical-axis unidirectional WEC.

CECO wave energy converter: Experimental proof of concept

2015 ◽  
Vol 7 (6) ◽  
pp. 061704 ◽  
Author(s):  
Paulo Rosa-Santos ◽  
Francisco Taveira-Pinto ◽  
Luís Teixeira ◽  
José Ribeiro
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Proof Of Concept ◽  
Energy Converter ◽  
Experimental Proof

scholarly journals Experimental Investigation of the Mooring System of a Wave Energy Converter in Operating and Extreme Wave Conditions

2020 ◽  
Vol 8 (3) ◽  
pp. 180 ◽  
Author(s):  
Sergej Antonello Sirigu ◽  
Mauro Bonfanti ◽  
Ermina Begovic ◽  
Carlo Bertorello ◽  
Panagiotis Dafnakis ◽  
...  
Keyword(s):  
Wave Energy ◽  
Careful Analysis ◽  
Wave Energy Converter ◽  
Extreme Wave ◽  
Energy Converter ◽  
Correct Operation ◽  
Wave Energy Converters ◽  
Rotational Joint ◽  
Wave Conditions ◽  
The University

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.

scholarly journals NUMERICAL MODELLING AND POWER TAKE OFF CHARACTERIZATION OF A WAVE ENERGY CONVERTER WITH BOUNDARY ELEMENT METHOD

2017 ◽  
pp. 27 ◽  
Author(s):  
Mario Lopez ◽  
Francisco Taveira-Pinto ◽  
Paulo Rosa-Santos
Keyword(s):  
Boundary Element Method ◽  
Numerical Modelling ◽  
Boundary Element ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Innovative Technology ◽  
Energy Converter ◽  
The Time Domain ◽  
The University ◽  
Element Method

This paper deals with the numerical modelling of an innovative technology for harnessing wave energy and its power take-off system. The investigated wave energy converter is CECO, a device based on the principles of oscillating bodies that is being developed at the Faculty of Engineering of the University of Porto, Portugal. The particularity of this concept lies on the relative motion between a floating part and a supporting one, which is restricted to translations along an inclined direction. First, the wave energy converter is modelled in the frequency domain by means of a panel model that is based on the boundary element method. Once obtained the frequency-dependent hydrodynamic coefficients of the floating part, the dynamic equation of motion is solved in the time domain by including, not only the hydrodynamic forces, but also the force of the power take-off system. The results prove the ability of the numerical modelling approach to simulate the behavior of the device and provide insight into its performance.

scholarly journals PHYSICAL AND NUMERICAL MODELING OF THE WAVECAT© WAVE ENERGY CONVERTER

2011 ◽  
Vol 1 (32) ◽  
pp. 64 ◽  
Author(s):  
Hernan Fernandez ◽  
Gregorio Iglesias ◽  
Rodrigo Carballo ◽  
Alberte Castro ◽  
Pedro Bartolomé
Keyword(s):  
Physical Model ◽  
Wave Energy ◽  
Wave Energy Converter ◽  
Intermediate Water ◽  
Energy Converter ◽  
Santiago De Compostela ◽  
Design Elements ◽  
Wave Flume ◽  
Fixed Model ◽  
The University

Wave energy presents a great potential in many coastal regions. This paper deals with WaveCat©, a new Wave Energy Converter (WEC) recently patented by the University of Santiago de Compostela. First, the WaveCat© concept and its main design elements. It is a floating WEC intended for intermediate water depths (50–75 m), whose principle of energy capture is wave overtopping. WaveCat© consists of two hulls, like a catamaran (hence its name); however, unlike a catamaran, the hulls are convergent so as to leave a wedge between them. Waves propagate into this wedge and, eventually, overtop the inner hull sides. Overtopping water is collected in onboard tanks and, subsequently, drained back to sea, propelling ultra-low head turbines in the process. The wave flume tests carried out on a 3D, fixed model at a 1:67 scale are presented. Development work is ongoing, including a numerical model—which is currently being validated based on the results from the physical model—and a 3D, floating physical model at a larger scale (1:30).

Wave Energy Converter Deployments at the Navy's Wave Energy Test Site: 2015‐2019

2020 ◽  
Vol 54 (6) ◽  
pp. 91-96
Author(s):  
Patrick Cross ◽  
Krishnakumar Rajagopalan
Keyword(s):  
Wave Energy ◽  
Test Site ◽  
Wave Energy Converter ◽  
Power Performance ◽  
Energy Converter ◽  
Sensing System ◽  
Look Ahead ◽  
A Site ◽  
The University ◽  
The U.S

AbstractA synopsis of wave energy converter (WEC) deployments at the U.S. Navy's Wave Energy Test Site (WETS), from the mid-2015 commissioning of the full three-berth site through 2019, is provided. This includes two deployments each of the Northwest Energy Innovations (NWEI) Azura device and the Fred. Olsen Ltd. BOLT Lifesaver, each with important modifications between deployments. The Azura was modified with a larger float and a heave plate, aimed at enhancing power performance, while the Lifesaver's second deployment addressed mooring challenges encountered in the first. Additionally, unique integration and deployment of a sophisticated environmental sensing system developed by the University of Washington, in which required power was drawn from the WEC itself, was achieved during this second Lifesaver deployment. A brief background of the site is included, as is a synopsis of two major efforts not directly related to WEC deployments—the development of a site-dedicated support vessel and work to redesign and make repairs to the WETS deep berth mooring systems, including the addition of a “no-WEC hawser” system to keep the moorings in tension between WEC deployments. Finally, a look ahead to WEC deployments planned in 2021‐2023 is provided.

scholarly journals Proof of Concept of a Breakwater-Integrated Hybrid Wave Energy Converter Using a Composite Modelling Approach

2021 ◽  
Vol 9 (2) ◽  
pp. 226
Author(s):  
Theofano I. Koutrouveli ◽  
Enrico Di Lauro ◽  
Luciana das Neves ◽  
Tomás Calheiros-Cabral ◽  
Paulo Rosa-Santos ◽  
...  
Keyword(s):  
Wave Energy ◽  
Wave Energy Converter ◽  
Electricity Production ◽  
Proof Of Concept ◽  
Energy Converter ◽  
Available Energy ◽  
Energy Technologies ◽  
Cost Of Energy ◽  
Wide Range ◽  
Modelling Approach

Despite the efforts of developers, investors and scientific community, the successful development of a competitive wave energy industry is proving elusive. One of the most important barriers against wave energy conversion is the efficiency of the devices compared with all the associated costs over the lifetime of an electricity generating plant, which translates into a very high Levelised Cost of Energy (LCoE) compared to that of other renewable energy technologies such as wind or solar photovoltaic. Furthermore, the industrial roll-out of Wave Energy Converter (WEC) devices is severely hampered by problems related to their reliability and operability, particularly in open waters and during harsh environmental sea conditions. WEC technologies in multi-purpose breakwaters—i.e., a structure that retains its primary function of providing sheltered conditions for port operations to develop and includes electricity production as an added co-benefit—appears to be a promising approach to improve cost-effectiveness in terms of energy production. This paper presents the proof of concept study of a novel hybrid-WEC (HWEC) that uses two well understood power generating technologies, air and water turbines, integrated in breakwaters, by means of a composite modelling approach. Preliminary results indicate: firstly, hybridisation is an adequate approach to harness the available energy most efficiently over a wide range of metocean conditions; secondly, the hydraulic performance of the breakwater improves; finally, no evident negative impacts in the overall structural stability specific to the integration were observed.

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