scholarly journals Damping Studies on PMLG-Based Wave Energy Converter under Oceanic Wave Climates

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 920
Author(s):  
Yue Hong ◽  
Irina Temiz ◽  
Jianfei Pan ◽  
Mikael Eriksson ◽  
Cecilia Boström
Keyword(s):  
Wave Energy ◽  
Energy Production ◽  
Full Range ◽  
Electrical Power ◽  
Damping Coefficient ◽  
Irregular Wave ◽  
Ocean Wave Energy ◽  
Optimal Damping ◽  
The Impact

Wave energy converters (WECs), which are designed to harvest ocean wave energy, have recently been improved by the installation of numerous conversion mechanisms; however, it is still difficult to find an appropriate method that can compromise between strong environmental impact and robust performance by transforming irregular wave energy into stable electrical power. To solve this problem, an investigation into the impact of varied wave conditions on the dynamics of WECs and to determine an optimal factor for WECs to comply with long-term impacts was performed. In this work, we researched the performance of WECs influenced by wave climates. We used a permanent magnet linear generator (PMLG)-based WEC that was invented at Uppsala University. The damping effect was first studied with a PMLG-type WEC. Then, a group of sea states was selected to investigate their impact on the power production of the WEC. Two research sites were chosen to investigate the WEC’s annual energy production as well as a study on the optimal damping coefficient impact. In addition, we compared the WEC’s energy production between optimal damping and constant damping under a full range of sea states at both sites. Our results show that there is an optimal damping coefficient that can achieve the WEC’s maximum power output. For the chosen research sites, only a few optimal damping coefficients were able to contribute over 90% of the WEC’s annual energy production. In light of the comparison between optimal and constant damping, we conclude that, for specific regions, constant damping might be a better choice for WECs to optimize long-term energy production.

scholarly journals Historical Evolution of the Wave Resource and Energy Production off the Chilean Coast over the 20th Century

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2289 ◽  
Author(s):  
Alain Ulazia ◽  
Markel Penalba ◽  
Arkaitz Rabanal ◽  
Gabriel Ibarra-Berastegi ◽  
John Ringwood ◽  
...  
Keyword(s):  
20Th Century ◽  
Wave Energy ◽  
West Coast ◽  
Energy Production ◽  
Energy Resource ◽  
The West ◽  
Chilean Coast ◽  
Resource Variability ◽  
The Impact

The wave energy resource in the Chilean coast shows particularly profitable characteristics for wave energy production, with relatively high mean wave power and low inter-annual resource variability. This combination is as interesting as unusual, since high energetic locations are usually also highly variable, such as the west coast of Ireland. Long-term wave resource variations are also an important aspect when designing wave energy converters (WECs), which are often neglected in resource assessment. The present paper studies the long-term resource variability of the Chilean coast, dividing the 20th century into five do-decades and analysing the variations between the different do-decades. To that end, the ERA20C reanalysis of the European Centre for Medium-Range Weather Forecasts is calibrated versus the ERA-Interim reanalysis and validated against buoy measurements collected in different points of the Chilean coast. Historical resource variations off the Chilean coast are compared to resource variations off the west coast in Ireland, showing a significantly more consistent wave resource. In addition, the impact of historical wave resource variations on a realistic WEC, similar to the Corpower device, is studied, comparing the results to those obtained off the west coast of Ireland. The annual power production off the Chilean coast is demonstrated to be remarkably more regular over the 20th century, with variations of just 1% between the different do-decades.

scholarly journals Optimal damping coefficient for a class of continuous contact models

2020 ◽  
Vol 50 (2) ◽  
pp. 169-188
Author(s):  
Mohammad Poursina ◽  
Parviz E. Nikravesh
Keyword(s):  
Contact Force ◽  
Analytical Formula ◽  
Coefficient Of Restitution ◽  
Damping Coefficient ◽  
Optimization Strategy ◽  
Continuous Contact ◽  
Optimal Damping ◽  
Wide Range ◽  
Contact Models ◽  
The Impact

Abstract In this study, we develop an analytical formula to approximate the damping coefficient as a function of the coefficient of restitution for a class of continuous contact models. The contact force is generated by a logical point-to-point force element consisting of a linear damper connected in parallel to a spring with Hertz force–penetration characteristic, while the exponent of deformation of the Hertz spring can vary between one and two. In this nonlinear model, it is assumed that the bodies start to separate when the contact force becomes zero. After separation, either the restitution continues or a permanent penetration is achieved. Therefore, this model is capable of addressing a wide range of impact problems. Herein, we apply an optimization strategy on the solution of the equations governing the dynamics of the penetration, ensuring that the desired restitution is reproduced at the time of separation. Furthermore, based on the results of the optimization process along with analytical investigations, the resulting optimal damping coefficient is analytically expressed at the time of impact in terms of system properties such as the effective mass, penetration velocity just before the impact, coefficient of restitution, and the characteristics of the Hertz spring model.

Impact of technical power take-off constraints on the power extraction of unidirectional and bidirectional point absorbers

2015 ◽  
Vol 34 (6) ◽  
pp. 1796-1806
Author(s):  
Alessandro Bozzetto ◽  
Ole Christian Spro ◽  
Elisabetta Tedeschi
Keyword(s):  
Wave Energy ◽  
Control Strategy ◽  
Energy Production ◽  
Power Performance ◽  
Content Type ◽  
Practical Applications ◽  
Power Extraction ◽  
Point Absorber ◽  
Point Absorbers ◽  
The Impact

Purpose – The purpose of this paper is to quantify the impact of the constraints of the power take-off system (PTO) on the power extraction of a point absorber wave energy converter (WEC). Such constraints include power, torque and maximum stroke limitations. Two different concepts, unidirectional and bidirectional point absorbers, are analysed, which both are relevant for practical applications in the wave energy industry. Design/methodology/approach – The two different cases of unidirectional and bidirectional point absorbers are analysed and directly compared. Moreover, a simplified control strategy is considered for the point absorber, which is based on a constant torque reference. The WEC performance is first evaluated in selected sea states and then the analysis is extended to assess the impact of the different solutions on the expected yearly wave energy production of the point absorber, when deployed at a specific location. The European Marine Energy Center (EMEC) is selected as the target site for the analysis. Findings – The analysis was performed in selected sea states and then it was extended to all the sea conditions occurring at the EMEC test site. The comparison between unidirectional and bidirectional operated devices suggested a clear superiority of the latter, ensuring similar power extraction at the expense of a halved required torque by the PTO. Moreover, a selective control strategy was implemented, and the results showed an increase in yearly energy production for the bidirectional device. Research limitations/implications – The study proved the importance of including the actual PTO constraints in the preliminary power assessment in order to avoid unrealistic overestimation of the expected power performance. Originality/value – The paper quantifies the power performance obtained with the application of such control strategy considering both unidirectional and bidirectional point absorbers. This analysis and comparison is extremely relevant since both unidirectional and bidirectional devices are reaching the market.

scholarly journals A multiobjective short-term optimal operation model for a cascade system of reservoirs considering the impact on long-term energy production

2015 ◽  
Vol 51 (5) ◽  
pp. 3353-3369 ◽  
Author(s):  
Bin Xu ◽  
Ping-An Zhong ◽  
Zachary Stanko ◽  
Yunfa Zhao ◽  
William W.-G. Yeh
Keyword(s):  
Energy Production ◽  
Optimal Operation ◽  
Operation Model ◽  
Cascade System ◽  
Short Term ◽  
Term Energy ◽  
The Impact

scholarly journals Estimation of future methane production from Hellenic landfills

2013 ◽  
Vol 11 (2) ◽  
pp. 162-171
Keyword(s):  
Methane Production ◽  
Energy Production ◽  
Phase Model ◽  
Methane Generation ◽  
Sanitary Landfills ◽  
Multi Phase ◽  
The Impact ◽  
The Eu

The main objective of this research was to predict expected methane generation in Hellenic sanitary landfills, in order to evaluate its potential for energy production and to ensure health and safety in and around these sites on the long term. The study was performed for the period 2008 – 2028 with the use of a multi-phase model and included also a sensitivity analysis in order to determine the impact of certain waste parameters. In this context, two ‘extreme’ reference scenarios were formulated and assessed, one anticipating fulfilment of the EU landfill directive (which sets limits to the amount of biodegradable and packaging materials to be deposited in sanitary landfills) whereas a second (do-nothing scenario) assuming no such timely compliance.

scholarly journals Grid Impact of a Wave Farm on its Local Network: Analysis of Voltage and Flicker Levels

2012 ◽  
Author(s):  
Anne Blavette ◽  
Dara L. O’Sullivan ◽  
Ray Alcorn ◽  
Anthony W. Lewis ◽  
Michael G. Egan
Keyword(s):  
Time Series ◽  
Wave Energy ◽  
Large Scale ◽  
Negative Impact ◽  
Electrical Power ◽  
Local Network ◽  
Wave Energy Converters ◽  
Wave Farm ◽  
The Impact ◽  
Energy Converters

Most oscillating wave energy converters without significant amounts of energy storage capacity generate significant electrical power fluctuations in the range of seconds. Because of these fluctuations, a wave farm may have a negative impact on the power quality of the local grid to which it is connected. Hence, the impact of these devices on both distribution and transmission networks needs to be well understood, before large scale wave farms can be allowed to connect to the grid. This paper details a case study on the impact of a wave farm on the distribution grid around the national wave test site of Ireland. The electrical power output of the oscillating water column (OWC) wave energy converters was derived from experimental time series produced in the context of the FP7 project “CORES”. The results presented in this paper consider voltage fluctuation levels and flicker levels for a typical time series. Simulations were performed using DIgSILENT simulation tool “PowerFactory”.

scholarly journals The Performance of a Spectral Wave Model at Predicting Wave Farm Impacts

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5728
Author(s):  
J. Cameron McNatt ◽  
Aaron Porter ◽  
Christopher Chartrand ◽  
Jesse Roberts
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Wave Interaction ◽  
Wave Model ◽  
Skill Score ◽  
Coastal Protection ◽  
Linear Wave ◽  
Ocean Wave Energy ◽  
Wave Farm ◽  
The Impact

For renewable ocean wave energy to support global energy demands, wave energy converters (WECs) will likely be deployed in large numbers (farms), which will necessarily change the nearshore environment. Wave farm induced changes can be both helpful (e.g., beneficial habitat and coastal protection) and potentially harmful (e.g., degraded habitat, recreational, and commercial use) to existing users of the coastal environment. It is essential to estimate this impact through modeling prior to the development of a farm, and to that end, many researchers have used spectral wave models, such as Simulating WAves Nearshore (SWAN), to assess wave farm impacts. However, the validity of the approaches used within SWAN have not been thoroughly verified or validated. Herein, a version of SWAN, called Sandia National Laboratories (SNL)-SWAN, which has a specialized WEC implementation, is verified by comparing its wave field outputs to those of linear wave interaction theory (LWIT), where LWIT is theoretically more appropriate for modeling wave-body interactions and wave field effects. The focus is on medium-sized arrays of 27 WECs, wave periods, and directional spreading representative of likely conditions, as well as the impact on the nearshore. A quantitative metric, the Mean Squared Skill Score, is used. Results show that the performance of SNL-SWAN as compared to LWIT is “Good” to “Excellent”.

scholarly journals Unlimited Energy Source: A Review of Ocean Wave Energy Utilization and Its Impact on the Environment

2021 ◽  
Vol 6 (1) ◽  
pp. 1-16
Author(s):  
Muhammad Satriawan ◽  
L Liliasari ◽  
Wawan Setiawan ◽  
Ade Gafar Abdullah
Keyword(s):  
Wave Energy ◽  
Alternative Energy ◽  
Wave Energy Converter ◽  
Energy Utilization ◽  
Ocean Wave ◽  
Energy Industry ◽  
Energy Converter ◽  
Ocean Wave Energy ◽  
The Government ◽  
The Impact

This paper aims to review the potential of wave energy in several countries, the wave energy converter technology that has been developed, and the impact of the installation of wave energy converter technology devices on the environment. In addition, it discusses the theoretical formulations and challenges in the development of energy converter technology in the future. Based on the detail analysis, the potential of ocean wave energy for alternative energy is very large but cannot be used optimally because the technology of wave energy converter that has been developed is still on a prototype scale. In addition, the impact of the use of ocean wave converters on the environment is insignificant compared with conventional energy. Finally, this study informs and recommends the government and the private sector to start investing in the ocean wave energy industry optimally in order to achieve a sustainable future.

scholarly journals Long-Term Performance Analysis Using TRNSYS Software of Hybrid Systems with PV-T

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6921
Author(s):  
Sebastian Pater
Keyword(s):  
Energy Production ◽  
Electric Energy ◽  
Electrical Energy ◽  
Climatic Conditions ◽  
One Year ◽  
Systems Simulation ◽  
Long Term Performance ◽  
Term Performance ◽  
The Impact

A hybrid photovoltaic-thermal collector (PV-T) with the capability to produce thermal energy and electrical energy simultaneously has attracted the attention of researchers, especially in terms of improving PV-T performance. This study analyses the work of four model installations with PV-T and other devices built in the transient systems simulation program. The novelty of this article lies in a long-term approach to the operation of PV-T panels under selected climatic conditions. Influence of the installation’s configuration on the obtained temperatures of solar cells, and, in consequence, on electric power generated by PV-T and the amount of heat produced during one year in a selected location is presented. Among others, the impact of the temperature coefficient of photovoltaic cells for long-term PV-T operation was analyzed in the paper. The results showed that the type of cell used may decrease the yearly electric energy production from PV-T even by 7%. On the other hand, intensification of the process of heat reception from PV-T using a heat pump increased this production by 6% in relation to the base model. The obtained research results indicate possible methods for improving the effectiveness of PV-T operation in a long-term aspect.

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