Special Issue "Renewable Energy 2018"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Energy".

Deadline for manuscript submissions: 15 April 2018

Special Issue Editor

Guest Editor
Prof. Dr. Tomonobu Senjyu

Faculty of Engineering, University of the Ryukyus, 1 Senbaru Nishihara-cho, Nakagami Okinawa 903-0213, Japan
Website | E-Mail
Phone: +81-98-895-8686
Fax: +81 895 8686
Interests: renewable energy; power systems; power electronics; system control; optimization; smart grid; energy storage; smart house; smart city; motor drives; artificial intelligence; electric vehicles

Special Issue Information

Dear Colleagues,

The Guest Editor is inviting submissions for a Special Issue of Applied Sciences on the subject area of "Renewable Energy 2018". Renewable energy is being introduced globally. Renewable energy is a promising and/or alternative energy resource in the world. This kind of energy reduces greenhouse gas compared with fossil resources. The introduction of renewable energy is environmental friendly and comprehensive in our society. However, highly-efficient and economic usage of renewable energy is a challenging task. We need to know the wide variety of knowledge for control, power electronics, power systems, etc. This Special Issue deals with recent state-of-the-art technology for renewable energy. These technologies increase the introduction of renewable energy in the world.

This Special Issue will focus on renewable energy and its applications. Topics of interest for publication include, but are not limited to: 

• Wind energy; 
• Solar energy; 
• Tidal energy; 
• Wave energy; 
• Biomass energy; 
• Energy storage; 
• Energy transportation; 
• Electrical power transmission; 
• Energy distribution; 
• Energy conversions; 
• Control technique for renewable energy; 
• Optimization technique for renewable energy; 
• Reduction of CO2 emission;
• Economic issues in renewable energy; 
• Hydrogen production from renewable energy.

Prof. Dr. Tomonobu Senjyu
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (5 papers)

View options order results:
result details:
Displaying articles 1-5
Export citation of selected articles as:

Research

Open AccessArticle Thermal Pre-Treatment of Sewage Sludge in a Lab-Scale Fluidized Bed for Enhancing Its Solid Fuel Properties
Appl. Sci. 2018, 8(2), 183; doi:10.3390/app8020183
Received: 5 January 2018 / Revised: 24 January 2018 / Accepted: 25 January 2018 / Published: 26 January 2018
PDF Full-text (1801 KB) | HTML Full-text | XML Full-text
Abstract
Thermal pre-treatment of non-lignocellulosic biomass, sewage sludge, using a lab-scale fluidized bed reactor was carried out in order to enhance its solid fuel properties. The influence of the torrefaction temperature range from 200–350 °C and 0–50 min residence time on the physical and
[...] Read more.
Thermal pre-treatment of non-lignocellulosic biomass, sewage sludge, using a lab-scale fluidized bed reactor was carried out in order to enhance its solid fuel properties. The influence of the torrefaction temperature range from 200–350 °C and 0–50 min residence time on the physical and chemical properties of the torrefied product was investigated. Properties of the torrefied product were analyzed on the basis of the degree of torrefaction, ultimate and proximate analysis, and gas analysis. An attempt was made to obtain the chemical exergy of sewage sludge. An elevated torrefaction temperature presented a beneficial impact on the degree of torrefaction and chemical exergy. Moreover, the effect of the torrefaction temperature and residence time on the elemental variation of sewage sludge exhibited an increase in the weight percentage of carbon while the H/C and O/C molar ratios deteriorated. Additionally, the product gas emitted during torrefaction was analyzed to study the pathway of hydrocarbons and oxygen containing compounds. The compounds with oxygen were emitted at higher temperatures in contrast to hydrocarbon gases. In addition, the study of various correlations for predicting the calorific value of torrefied sewage sludge was made. Full article
(This article belongs to the Special Issue Renewable Energy 2018)
Figures

Open AccessArticle Low-Voltage Ride-Through Control Strategy for a Grid-Connected Energy Storage System
Appl. Sci. 2018, 8(1), 57; doi:10.3390/app8010057
Received: 13 November 2017 / Revised: 27 December 2017 / Accepted: 28 December 2017 / Published: 2 January 2018
PDF Full-text (6507 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a low-voltage ride-through (LVRT) control strategy for grid-connected energy storage systems (ESSs). In the past, researchers have investigated the LVRT control strategies to apply them to wind power generation (WPG) and solar energy generation (SEG) systems. Regardless of the energy
[...] Read more.
This paper presents a low-voltage ride-through (LVRT) control strategy for grid-connected energy storage systems (ESSs). In the past, researchers have investigated the LVRT control strategies to apply them to wind power generation (WPG) and solar energy generation (SEG) systems. Regardless of the energy source, the main purpose of the LVRT control strategies is to inject reactive power into the grid depending on the grid-code regulations using the grid-side inverter; the proposed LVRT control strategy for grid-connected ESSs also has the same purpose. However, unlike the WPG and SEG systems having unidirectional power flow, grid-connected ESSs have a bidirectional power flow. Therefore, the charging condition of the grid-connected ESSs should be considered for the LVRT control strategy. The proposed LVRT control strategy for grid-connected ESSs determines the injection quantity of the active and reactive currents, and the strategy depends on the voltage drop ratio of the three-phase grid. Additionally, in this paper, we analyzed the variations of the point of common coupling (PCC) voltage depending on the phase of the reactive current during the charging and discharging conditions. The validity of the proposed LVRT control strategy is verified and the variations of the PCC voltage of the grid-connected ESS are analyzed by simulation and experimental results. Full article
(This article belongs to the Special Issue Renewable Energy 2018)
Figures

Open AccessArticle Robust Control Examples Applied to a Wind Turbine Simulated Model
Appl. Sci. 2018, 8(1), 29; doi:10.3390/app8010029
Received: 25 November 2017 / Revised: 16 December 2017 / Accepted: 19 December 2017 / Published: 26 December 2017
PDF Full-text (706 KB) | HTML Full-text | XML Full-text
Abstract
Wind turbine plants are complex dynamic and uncertain processes driven by stochastic inputs and disturbances, as well as different loads represented by gyroscopic, centrifugal and gravitational forces. Moreover, as their aerodynamic models are nonlinear, both modeling and control become challenging problems. On the
[...] Read more.
Wind turbine plants are complex dynamic and uncertain processes driven by stochastic inputs and disturbances, as well as different loads represented by gyroscopic, centrifugal and gravitational forces. Moreover, as their aerodynamic models are nonlinear, both modeling and control become challenging problems. On the one hand, high-fidelity simulators should contain different parameters and variables in order to accurately describe the main dynamic system behavior. Therefore, the development of modeling and control for wind turbine systems should consider these complexity aspects. On the other hand, these control solutions have to include the main wind turbine dynamic characteristics without becoming too complicated. The main point of this paper is thus to provide two practical examples of the development of robust control strategies when applied to a simulated wind turbine plant. Extended simulations with the wind turbine benchmark model and the Monte Carlo tool represent the instruments for assessing the robustness and reliability aspects of the developed control methodologies when the model-reality mismatch and measurement errors are also considered. Advantages and drawbacks of these regulation methods are also highlighted with respect to different control strategies via proper performance metrics. Full article
(This article belongs to the Special Issue Renewable Energy 2018)
Figures

Figure 1

Open AccessArticle Utilizing Downdraft Fixed Bed Reactor for Thermal Upgrading of Sewage Sludge as Fuel by Torrefaction
Appl. Sci. 2017, 7(11), 1189; doi:10.3390/app7111189
Received: 31 October 2017 / Revised: 13 November 2017 / Accepted: 15 November 2017 / Published: 18 November 2017
PDF Full-text (2302 KB) | HTML Full-text | XML Full-text
Abstract
A lab-scale downdraft fixed bed reactor was used for the study of sewage sludge, a non-lignocellulosic biomass, torrefaction to enhance the thermochemical properties of sewage sludge. The torrefaction was carried out for a temperature range of 200–350 °C and a residence time of
[...] Read more.
A lab-scale downdraft fixed bed reactor was used for the study of sewage sludge, a non-lignocellulosic biomass, torrefaction to enhance the thermochemical properties of sewage sludge. The torrefaction was carried out for a temperature range of 200–350 °C and a residence time of 0–50 min. Degree of torrefaction, torrefaction index, chemical exergy, gas analysis, and molar ratios were taken into account to analyze the torrefied product with respect to torrefaction temperature. The effect of torrefaction temperature was very pronounced and the temperature range of 250–300 °C was considered to be the optimum torrefaction temperature range for sewage sludge. Chemical exergy, calorific value and torrefaction index were significantly influenced by the change in the relative carbon content resulting in decrease of the O/C and H/C molar ratios. Full article
(This article belongs to the Special Issue Renewable Energy 2018)
Figures

Figure 1

Open AccessArticle Spectral Correction of CPV Modules Equipped with GaInP/GaInAs/Ge Solar Cells and Fresnel Lenses
Appl. Sci. 2017, 7(8), 842; doi:10.3390/app7080842
Received: 24 July 2017 / Revised: 10 August 2017 / Accepted: 11 August 2017 / Published: 16 August 2017
Cited by 3 | PDF Full-text (804 KB) | HTML Full-text | XML Full-text
Abstract
Photovoltaic (PV) devices are spectrally selective, and their performance is influenced by unavoidable spectral variations. In addition, multijunction-based concentrating photovoltaic (CPV) devices show a strong spectral dependence due to the series connection of various junctions with different absorption bands, and also due to
[...] Read more.
Photovoltaic (PV) devices are spectrally selective, and their performance is influenced by unavoidable spectral variations. In addition, multijunction-based concentrating photovoltaic (CPV) devices show a strong spectral dependence due to the series connection of various junctions with different absorption bands, and also due to the use of concentrator optics. In this work, the accuracy of a new set of analytical equations that quantify the spectral impact caused by the changes in air mass (AM), aerosol optical depth (AOD) and precipitable water (PW) is discussed. Four different CPV devices based on lattice-matched and metamorphic triple-junction solar cells and a poly(methyl methacrylate) (PMMA) and silicon-on-glass (SoG) Fresnel lenses are considered. A long-term outdoor experimental campaign was carried out at the Centre for Advanced Studies on Energy and Environment (CEAEMA) of the University of Jaén, Spain. Results show a high accuracy in the estimations of the spectral factor (SF), with an average mean absolute percentage error (MAPE) within 0.91% and a mean relative error (MRE) within −0.32%. Full article
(This article belongs to the Special Issue Renewable Energy 2018)
Figures

Figure 1

Back to Top