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5th Anniversary of Energy Section—Recent Advances in Energy
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5th Anniversary of Energy Section—Recent Advances in Energy

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

Deadline for manuscript submissions: closed (10 August 2022) | Viewed by 55503

Special Issue Editors

Prof. Dr. Pooya Davari

E-Mail Website
Guest Editor
Department of Energy Technology, Aalborg University, Pontoppidanstraede 111, 9220 Aalborg, Denmark
Interests: active front-end rectifiers; harmonic mitigation in adjustable-speed drives; electromagnetic interference in power electronics; high-power-density power electronic systems; pulsed power application
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Enrico Cagno

E-Mail Website
Guest Editor
Department of Management, Economics and Industrial Engineering, Politecnico Di Milano, Via Lambruschini 4/b, building 26/B, 20156 Milano, Italy
Interests: energy efficiency; energy use; energy efficiency measures (EEMs); adoption process; barriers; drivers; non-energy benefits; multiple benefits; manufacturing; small–medium enterprises (SMEs)
Special Issues, Collections and Topics in MDPI journals
Dr. Mohsen Soltani

E-Mail Website
Guest Editor
Department of Energy Technology, Aalborg University, Niels Bohrs Vej 8, 6700 Esbjerg, Denmark
Interests: fault diagnosis; control systems; modeling; wind power; offshore wind turbines and wind farms; energy islands; control of power electronic systems and microgrids; energy management systems
Special Issues, Collections and Topics in MDPI journals
Dr. Edris Pouresmaeil

E-Mail Website
Guest Editor
Department of Electrical Engineering and Automation, Aalto University, 02150 Espoo, Finland
Interests: control of power electronics in power systems; integration of large-scale renewable energy sources into the low-inertia power grid; ICT-based power networks; smart grids; microgrid operation and control; simulator design and software development for smart grid applications
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Alongside the growing population and living standards, the demand for energy is rising exponentially. In the development of modern societies, one of the key factors is to mitigate climate change and achieve carbon neutrality by saving energy and becoming more independent of fossil-fuel-based energy resources. Therefore, there has been a shift in the energy paradigm to carbon-free technologies and applications in order to develop long-term sustainable energy generation and transformation. In order to fulfill the global green transition goals, there is a need for deployment of innovative solutions that aid the green transition through solving challenges for climate and environment. Among the many introduced technologies, those supporting the growth of clean energy and that improve energy efficiency are currently in the spotlight.

This year marks the 5th year since the inception of the Energy Section. To celebrate such an achievement with all of you, in this Special Issue, we are seeking high-quality submissions that highlight emerging technologies and applications addressing recent advances and breakthroughs in the field of energy production, harvesting, transformation, storage and consumption. The topics of interest include but are not limited to:

Proposed list of keywords:

  • Modern energy systems;
  • Renewable energy generation;
  • Energy storage;
  • Energy harvesting;
  • Power-to-X;
  • Low-carbon technologies in energy systems;
  • E-mobility;
  • Analysis of energy systems;
  • Energy hubs and energy islands;
  • Advanced power electronic technologies for energy systems;
  • Renewable energy generation (offshore, onshore, marine-based);
  • Digital technologies and AI for energy efficiency;
  • Energy management;
  • Energy auditing;
  • Energy end-use data monitoring;
  • Energy optimization;
  • Barriers and drivers to energy efficiency;
  • Supply chain.

Prof. Dr. Pooya Davari
Prof. Dr. Enrico Cagno
Dr. Mohsen Soltani
Prof. Dr. Edris Pouresmaeil
Guest Editors

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 submissions that pass pre-check are 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 semimonthly 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 2400 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.

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14 pages, 2708 KiB  
Article
Energy Forecasting in a Public Building: A Benchmarking Analysis on Long Short-Term Memory (LSTM), Support Vector Regression (SVR), and Extreme Gradient Boosting (XGBoost) Networks
by Junhui Huang, Mohammed Algahtani and Sakdirat Kaewunruen
Appl. Sci. 2022, 12(19), 9788; https://doi.org/10.3390/app12199788 - 28 Sep 2022
Cited by 18 | Viewed by 1821
Abstract
A primary energy consumption and CO2 emission source stems from buildings and infrastructures due to rapid urbanisation and social development. An accurate method to forecast energy consumption in a building is thus critically needed to enable successful management of adaptive energy consumption [...] Read more.
A primary energy consumption and CO2 emission source stems from buildings and infrastructures due to rapid urbanisation and social development. An accurate method to forecast energy consumption in a building is thus critically needed to enable successful management of adaptive energy consumption and ease the level of CO2 emission. However, energy forecasting for buildings, especially residential buildings, has several challenges, such as significant variations in energy usage patterns due to unpredicted demands of the residences and some intricate factors, which can randomly affect the patterns. Traditional forecasting approaches require a tremendous number of inputs needed for building physic models and variations often exist between as-built and as-designed buildings in reality. Most recent studies have adopted only ambient weather conditions, building components, and the occupant’s behaviours. As a result, in order to take into account the complexity of factors that can affect the building energy model development and its computation, we develop advanced machine learning models driven by the inherent electricity consumption pattern associated with the day and time. In this study, we demonstrate benchmarking results derived from three different machine learning algorithms, namely SVR, XGBoost, and LSTM, trained by using 1-year datasets with sub-hourly (30 min) temporal granularity to determine the outperformed predictor. Ultimately, the machine learning model robustness and performance on a basis of the coefficient of variation (CV) obtained by the SVR is benchmarked across XGBoost and LSTM trained by the same datasets containing attributes related to the building type, data size, and temporal granularity. The insight stemming from this study indicates that the suitable choice of the machine learning models for building energy forecasts largely depends on the natural characteristics of building energy data. Hyperparameter tuning or mathematical modification within an algorithm may not be sufficient to attain the most accurate machine learning model for building energy forecast. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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22 pages, 7877 KiB  
Article
A Systematic Control Design Method with Active Damping Control in Voltage Source Converters
by Hosein Gholami-Khesht, Pooya Davari, Chao Wu and Frede Blaabjerg
Appl. Sci. 2022, 12(17), 8893; https://doi.org/10.3390/app12178893 - 05 Sep 2022
Viewed by 1201
Abstract
This paper proposes a systematic control design method for active damping control of grid-connected voltage source converters (VSCs). The proposed control method considers the conventional cascaded control loops and improves them by including additional states feedback-based active damping. In such a way, all [...] Read more.
This paper proposes a systematic control design method for active damping control of grid-connected voltage source converters (VSCs). The proposed control method considers the conventional cascaded control loops and improves them by including additional states feedback-based active damping. In such a way, all control gains are lumped into one control gain matrix based on the proposed formulation. The lumping of all control gains into one matrix leads to a linear optimization problem, so different techniques can be used to calculate control gains. This work calculates them by using a simple but effective optimal control theorem as a noteworthy feature. The proposed control method can overcome the challenges of designing multiple control loops, evaluating wide time scale dynamics, and tuning required control parameters. Moreover, direct relationships between the proposed tuning parameters and system well-known stability and performance indicators such as maximum damping factor, minimum damping ratio, and the control efforts are identified, providing good physical insight. Finally, the proposed control structure and optimal gain calculations ensure power converter robustness against uncertainties in the grid’s short-circuit ratio (SCR) and different operating-point conditions. When the grid’s SCR changes from 10 (strong grid condition) to 1 (ultra-weak grid condition), the system under the proposed control method maintains good stability margins and simultaneously provides a fast dynamic response by facilitating the implementation of a high-bandwidth phase-locked loop (PLL). The performance of the proposed control strategy was investigated analytically and practically by conducting eigenvalue analysis, simulations, and experiments. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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17 pages, 1391 KiB  
Article
A Machine Learning Method for Modeling Wind Farm Fatigue Load
by Yizhi Miao, Mohsen N. Soltani and Amin Hajizadeh
Appl. Sci. 2022, 12(15), 7392; https://doi.org/10.3390/app12157392 - 22 Jul 2022
Cited by 2 | Viewed by 1361
Abstract
Wake steering control can significantly improve the overall power production of wind farms. However, it also increases fatigue damage on downstream wind turbines. Therefore, optimizing fatigue loads in wake steering control has become a hot research topic. Accurately predicting farm fatigue loads has [...] Read more.
Wake steering control can significantly improve the overall power production of wind farms. However, it also increases fatigue damage on downstream wind turbines. Therefore, optimizing fatigue loads in wake steering control has become a hot research topic. Accurately predicting farm fatigue loads has always been challenging. The current interpolation method for farm-level fatigue loads estimation is also known as the look-up table (LUT) method. However, the LUT method is less accurate because it is challenging to map the highly nonlinear characteristics of fatigue load. This paper proposes a machine-learning algorithm based on the Gaussian process (GP) to predict the farm-level fatigue load under yaw misalignment. Firstly, a series of simulations with yaw misalignment were designed to obtain the original load data, which considered the wake interaction between turbines. Secondly, the rainflow counting and Palmgren miner rules were introduced to transfer the original load to damage equivalent load. Finally, the GP model trained by inputs and outputs predicts the fatigue load. GP has more accurate predictions because it is suitable for mapping the nonlinear between fatigue load and yaw misalignment. The case study shows that compared to LUT, the accuracy of GP improves by 17% (RMSE) and 0.6% (MAE) at the blade root edgewise moment and 51.87% (RMSE) and 1.78% (MAE) at the blade root flapwise moment. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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21 pages, 7823 KiB  
Article
Low-Cost Three-Quadrant Single Solar Cell I-V Tracer
by José Ignacio Morales-Aragonés, Víctor Alonso Gómez, Sara Gallardo-Saavedra, Alberto Redondo-Plaza, Diego Fernández-Martínez and Luis Hernández-Callejo
Appl. Sci. 2022, 12(13), 6623; https://doi.org/10.3390/app12136623 - 30 Jun 2022
Cited by 3 | Viewed by 1555
Abstract
An I-V curve measurement technique is one of the most important techniques available for characterising photovoltaic cells. Measuring an accurate I-V curve at the single-cell level is a challenging task because of the low voltages and high currents implied, [...] Read more.
An I-V curve measurement technique is one of the most important techniques available for characterising photovoltaic cells. Measuring an accurate I-V curve at the single-cell level is a challenging task because of the low voltages and high currents implied, requiring the management of very low impedances. In this paper, the authors propose a low-cost device for I-V curve measurements of single (or small amounts) of cells in a series based on the charge transfer between two capacitors of equal capacitance. Our measurement strategy allows us to trace the usual first quadrant curve (the normal working region of solar cells) as well as the second and fourth quadrants of the I-V curve, which are quite important for research purposes. A prototype was built to demonstrate the feasibility and successful measurements of the three-quadrant I-V curve, obtained for more than 20 different cells. To use the device in a laboratory, without depending on the solar irradiation, a modular platform was 3D-printed, integrating a board with infrared LEDs as irradiating devices, and housing (to place the solar cell under test). The result is a useful low-cost setup for three-quadrant I-V curve tracing that works as expected. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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16 pages, 9001 KiB  
Article
Virtual Synchronous Machine Control of RES Plants in Isolated Power Systems
by Jaser A. Sa’ed, Salvatore Favuzza, Milagros Amparo Navarro Navia and Gaetano Zizzo
Appl. Sci. 2022, 12(12), 5920; https://doi.org/10.3390/app12125920 - 10 Jun 2022
Cited by 2 | Viewed by 1220
Abstract
Because of the increase in renewable energy sources (RESs) share, new control strategies of isolated power systems have been developed to improve the frequency and voltage stability of inverter-interfaced RESs. A voltage source converter (VSC) with a virtual synchronous machine (VSM) is among [...] Read more.
Because of the increase in renewable energy sources (RESs) share, new control strategies of isolated power systems have been developed to improve the frequency and voltage stability of inverter-interfaced RESs. A voltage source converter (VSC) with a virtual synchronous machine (VSM) is among the most promising control schemes. This paper demonstrates how VSM control of inverter-interfaced RES can be efficiently used to improve the dynamic stability in small isolated power systems. In the proposed analysis, the RESs of a Mediterranean island are assumed interfaced to the grid by VSCs with a swing controller and a vector-current controller (VCC) with two different options for the reference current (RC) to regulate the voltage at the point of common coupling (PCC) and the real power output. The system is modelled in a PSCAD environment, and the behavior of the control is tested in the case of a phase-to-phase fault. The results of the simulations for different scenarios and values for the control parameters show the effectiveness of the control in small isolated grids. Finally, the level of grid power quality is verified via harmonic analysis of the PCC voltage. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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15 pages, 4345 KiB  
Article
Improved Dynamic Power Flow Model with Frequency Regulation by DFIG Integrated through VSC-HVDC Considering Governor Delay of SG
by Tingting Sun and Jiejie Huang
Appl. Sci. 2022, 12(11), 5447; https://doi.org/10.3390/app12115447 - 27 May 2022
Cited by 1 | Viewed by 1195
Abstract
The doubly-fed induction generators (DFIGs) integrated to the grid through the voltage source converter-high voltage direct current (VSC-HVDC), the cascaded droop control from the system frequency to the DC voltage, then to the active output of the DFIG, was applied to enhance the [...] Read more.
The doubly-fed induction generators (DFIGs) integrated to the grid through the voltage source converter-high voltage direct current (VSC-HVDC), the cascaded droop control from the system frequency to the DC voltage, then to the active output of the DFIG, was applied to enhance the frequency regulation capability of the power system. The improved dynamic power flow (DPF) model was newly proposed to quantify the frequency response of the coordinated regulation with the inertia of the VSC-HVDC and the DFIGs, and the primary regulation of the synchronous generators (SGs) and the DFIGs. New features of the proposed model include: (i) the SGs’ output in the DPF considering the governor delay, (ii) setting of the virtual inertia of the VSC-HVDC within the DC voltage constraint, and (iii) variable inertia of the DFIGs following changing the kinetic energy of the rotor. The numerical results show the feasibility of the proposed model, and validate the regulation effect and accuracy of the modified inertia of the DFIGs and the maximized virtual inertia of the VSC-HVDC. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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14 pages, 14924 KiB  
Article
Robustness of Model-Predictive and Passivity-Based Control in the Three-Phase DC/AC Converter Application
by Łukasz Dyga, Mohammed Alhasheem, Pooya Davari and Zbigniew Rymarski
Appl. Sci. 2022, 12(9), 4329; https://doi.org/10.3390/app12094329 - 25 Apr 2022
Cited by 4 | Viewed by 1551
Abstract
In modern controller design, various solutions for controlling power converter systems can be found depending on their applications, speed of working, pulse width modulation (PWM) techniques, switching frequencies—fc, and different load types. The need to manipulate control parameters can be [...] Read more.
In modern controller design, various solutions for controlling power converter systems can be found depending on their applications, speed of working, pulse width modulation (PWM) techniques, switching frequencies—fc, and different load types. The need to manipulate control parameters can be often observed in classical structures, e.g., well-known PID, repetitive, or deadbeat control particularly sensitive to distinct parameters uncertainties. The purpose of this paper is to present an improved version of controllers designated for a UPS that will be considerably resistant to model changes. Proposed control techniques are independent of unexpected output filter changes: Lf—filter coil inductance and Cf—filter capacitor conductance. The second aspect of this paper is to compare effectiveness of modified predictive MPC (model-predictive control) and feedback PBC (passivity-based control) controllers in reducing output voltage total harmonic distortion (THD) for various load values. The biggest distortions of output voltage were observed during experiments with nonlinear RC load. Both simulation and experimental verification of mismatching parameters were performed and examined. Thanks to the proposed solution, the output voltage THDv quality factor was reduced below 8% in an efficient way for all the applied loads and stayed at the level of 1% when well-matched filter parameters were provided. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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15 pages, 6290 KiB  
Article
A Predictive Reliability Model to Assess the Performance of Photovoltaic Systems
by Nahed Solouma and Amal El Berry
Appl. Sci. 2022, 12(6), 2885; https://doi.org/10.3390/app12062885 - 11 Mar 2022
Cited by 2 | Viewed by 1609
Abstract
Clean energy is extremely important not only because of economic purposes but also for health considerations. The use of photovoltaic (PV) systems is growing, with the increased needs for electricity. This requires more attention to research of PV systems. In this study, a [...] Read more.
Clean energy is extremely important not only because of economic purposes but also for health considerations. The use of photovoltaic (PV) systems is growing, with the increased needs for electricity. This requires more attention to research of PV systems. In this study, a method to predict the expected lifetime based on the reliability of system performance is proposed. Geographical data were collected near two different locations: Cairo, Egypt and Riyadh, Saudi Arabia. The PV system was simulated with inputs from collected data to obtain the device factors and system responses. To study the significance of inputs and device parameters on the system responses, the Taguchi OA method was used. The probability density function (pdf) of the time of acceptable performance was estimated from the simulation data. A reliability analysis method was applied to the obtained pdf to estimate the reliability function, lifetime or mean life, reliable life, and rate of failure of the used PV system as assessment factors. The results showed that the system efficiency is highly dependent on the ambient temperature, while the performance ratio depends on many variables. The reliability analysis revealed that the field orientation of 30° tilt and 20° azimuth and of 30° tilt and 30° azimuth are best for near Cairo and near Riyadh, respectively. These orientations lead to the longest mean life of 772.25 and 688.36 months for Cairo and Riyadh, respectively. It also resulted in the lowest failure rates of 0.001295 and 0.001228 per month for both regions. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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20 pages, 3578 KiB  
Article
Regional Adaptability Analysis of Solar Roof Utilization Technologies in China
by Qingqing Li, Jianhua Fan and Junpeng Huang
Appl. Sci. 2022, 12(6), 2792; https://doi.org/10.3390/app12062792 - 09 Mar 2022
Cited by 3 | Viewed by 1450
Abstract
Considering the vast areas of building rooftops and the fast development of solar utilization technologies, this paper aims to analyze the regional adaptability of solar roof utilization technologies for buildings in China. All provinces and cities in China are divided into 13 zones [...] Read more.
Considering the vast areas of building rooftops and the fast development of solar utilization technologies, this paper aims to analyze the regional adaptability of solar roof utilization technologies for buildings in China. All provinces and cities in China are divided into 13 zones based on their economic development, thermal climate division, and availability of solar energy resources. Over 100 buildings are investigated, and the information of 28 buildings is analyzed to finally identify 18 typical building types. A new evaluation method is developed for both solar heating systems and solar PV. An adaptability index is developed considering the energy conservation, environment effect, and economy benefit of the systems. The developed method is used to evaluate the solar utilization technologies applied on the 18 buildings across 13 zones. The result show that the average adaptability index values for solar thermal technology and solar PV technology are 2.54 and 1.63, respectively. The solar heating system has a shorter payback time than the solar PV system for most regions of China and therefore is more favored. Recommendations on supporting policies and measures are given for policy makers with an aim to promote the utilization efficiency of building roofs. This paper provides references for the selection and application of relevant solar utilization technologies on building roofs. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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16 pages, 6678 KiB  
Article
Single-Phase, Bidirectional, 7.7 kW Totem Pole On-Board Charging/Discharging Infrastructure
by Vinit Kumar and KangHyun Yi
Appl. Sci. 2022, 12(4), 2236; https://doi.org/10.3390/app12042236 - 21 Feb 2022
Cited by 4 | Viewed by 3443
Abstract
In the present scenario of the fossil fuel crisis, a shift from conventional transportation to electric vehicles (EVs) is the goal, and it is necessary to make it economically feasible. Developing an efficient charger with mid-range power level may successfully resolve this problem. [...] Read more.
In the present scenario of the fossil fuel crisis, a shift from conventional transportation to electric vehicles (EVs) is the goal, and it is necessary to make it economically feasible. Developing an efficient charger with mid-range power level may successfully resolve this problem. In this direction, an EV charging infrastructure has been proposed to achieve grid-to-vehicle (G2V) charging, with vehicle-to-grid (V2G) capability. In G2V mode, the proposed infrastructure consists of an on-board, single-phase, 7.7 kW totem pole converter in continuous conduction mode to achieve high-power factor correction (PFC). Additionally, instead of conventional Si power MOSFET, an SiC-based converter is introduced to lower the switching losses at high switching frequency with smaller filters. Using an SiC-based converter leads to increased efficiency (more than 98%) and reduced total harmonic distortion (less than 5%), making the system economical. Simultaneously, to make the system more economical, the proposed converter works as an inverter to feedback the power to the grid in V2G mode. Furthermore, to analyse the feasibility, the proposed infrastructure has been simulated and its performance is validated using the simpower tool in MATLAB/Simulink environment. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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12 pages, 1632 KiB  
Article
Overview of Power Electronic Converter Topologies Enabling Large-Scale Hydrogen Production via Water Electrolysis
by Mengxing Chen, Shih-Feng Chou, Frede Blaabjerg and Pooya Davari
Appl. Sci. 2022, 12(4), 1906; https://doi.org/10.3390/app12041906 - 11 Feb 2022
Cited by 29 | Viewed by 10650
Abstract
Renewable power-to-hydrogen (P2H) technology is one of the most promising solutions for fulfilling the increasing global demand for hydrogen and to buffer large-scale, fluctuating renewable energies. The high-power, high-current ac/dc converter plays a crucial role in P2H facilities, transforming medium-voltage (MV) ac power [...] Read more.
Renewable power-to-hydrogen (P2H) technology is one of the most promising solutions for fulfilling the increasing global demand for hydrogen and to buffer large-scale, fluctuating renewable energies. The high-power, high-current ac/dc converter plays a crucial role in P2H facilities, transforming medium-voltage (MV) ac power to a large dc current to supply hydrogen electrolyzers. This work introduces the general requirements, and overviews several power converter topologies for P2H systems. The performances of different topologies are evaluated and compared from multiple perspectives. Moreover, the future trend of eliminating the line frequency transformer (LFT) is discussed. This work can provide guidance for future designing and implementing of power-electronics-based P2H systems. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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14 pages, 2925 KiB  
Article
Stochastic Approach to Hosting Limit of Transmission System and Improving Method Utilizing HVDC
by Dongyeong Lee, Junghun Lee and Gilsoo Jang
Appl. Sci. 2022, 12(2), 696; https://doi.org/10.3390/app12020696 - 11 Jan 2022
Cited by 2 | Viewed by 1386
Abstract
According to the global de-carbonization trends, renewable energy integration has become an increasingly important issue in power systems. To achieve 100% renewable energy integration and operate a system with these resources, it is necessary to appropriately evaluate the system hosting capability and prepare [...] Read more.
According to the global de-carbonization trends, renewable energy integration has become an increasingly important issue in power systems. To achieve 100% renewable energy integration and operate a system with these resources, it is necessary to appropriately evaluate the system hosting capability and prepare appropriate planning and operation strategies using the evaluation result. So far, these interests have focused particularly on distribution-level systems. However, although the hosting limit in transmission-level systems requires further consideration, previous study is limited. This study introduces the constraints on the transmission-level hosting limit. In addition, a stochastic estimation of the hosting limit methodology in the transmission system and the use of a high voltage direct current system to improve hosting capacity are proposed and evaluated. Moreover, these methodology-based simulations are conducted using possible scenarios on the IEEE 39 bus system with some constraints, and the simulation results are presented herein. The results showed that the HVDC location selection and operation using the proposed method and optimization technique is appropriate. The strategy can be used to integrate more renewable energy. Furthermore, the proposed methodology can be applied to renewable energy integration scenario establishing a plan. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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28 pages, 3714 KiB  
Article
Assessment of the Impacts of Climate Change on Power Systems: The Italian Case Study
by Giuseppe Marco Tina and Claudio F. Nicolosi
Appl. Sci. 2021, 11(24), 11821; https://doi.org/10.3390/app112411821 - 13 Dec 2021
Cited by 6 | Viewed by 2135
Abstract
Climate change due to the greenhouse effect will affect meteorological variables, which in turn will affect the demand for electrical energy and its generation in coming years. These impacts will become increasingly important in accordance with the increasing penetration of renewable, non-programmable energy [...] Read more.
Climate change due to the greenhouse effect will affect meteorological variables, which in turn will affect the demand for electrical energy and its generation in coming years. These impacts will become increasingly important in accordance with the increasing penetration of renewable, non-programmable energy sources (e.g., wind and solar). Specifically, the speed and amplitude of power system transformation will be different from one country to another according to many endogenous and exogenous factors. Based on a literature review, this paper focuses on the impact of climate change on the current, and future, Italian power system. The paper shows a wide range of results, due not just to the adopted climate change models used, but also to the models used to assess the impact of meteorological variables on electricity generation and demand. Analyzing and interpreting the reasons for such differences in the model results is crucial to perform more detailed numerical analyses on the adequacy and reliability of power systems. Concerning Italian future scenarios, the double impact of uncertainties in national policies and changes in power plant productivity and demand, has been considered and addressed. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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12 pages, 917 KiB  
Article
Simulation and Exergy Analysis of a Refrigeration System Using an Open-Source Web-Based Interactive Tool—Comparison of the Conventional Approach and a Novel One for Avoidable Exergy Destruction Estimation
by Volodymyr Voloshchuk, Paride Gullo, Eugene Nikiforovich and Nadia Buyak
Appl. Sci. 2021, 11(23), 11535; https://doi.org/10.3390/app112311535 - 06 Dec 2021
Cited by 2 | Viewed by 1965
Abstract
Avoidable endogenous/exogenous parts of the exergy destruction in the components of an energy conversion system can be computed by applying advanced exergy analysis. Their calculation is crucial for the correct assessment of the real thermodynamic enhancement achievable by the investigated energy conversion system. [...] Read more.
Avoidable endogenous/exogenous parts of the exergy destruction in the components of an energy conversion system can be computed by applying advanced exergy analysis. Their calculation is crucial for the correct assessment of the real thermodynamic enhancement achievable by the investigated energy conversion system. This work proposes a new approach to estimate the avoidable exergy destruction rates of system components, being more rigorous compared to the conventional method due to the elimination of the need for the implementation of theoretical assumptions associated with the idealization of processes. An open-source web-based interactive tool was implemented to contrast the results of the conventional advanced exergy analysis to those involving the new approach for avoidable exergy destruction estimation. The comparison was based on the same case study, i.e., a refrigeration system selected from the literature. It was observed that the developed tool can be properly employed for comparing the two approaches within exergy analyses, and the results obtained presented some differences for the compressor and the condenser. Compared to the new approach, the existing methodology of advanced exergy analysis suggests lower values of the avoidable part of exergy destruction, which can be reduced by improving the efficiency of the compressor and the condenser. Moreover, the avoidable parts of exergy destruction, which could be removed within these components by improving the efficiencies of the remaining components, were higher in the case of the application of the existing advanced exergetic analysis as compared with the findings obtained by the proposed approach. These differences were due to the impossibility of the existing advanced exergy analysis to implement complete thermodynamic “idealization” for the condenser and evaporator. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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16 pages, 2900 KiB  
Article
Comparative Evaluation on Combustion and Emission Characteristics of a Diesel Engine Fueled with Crude Palm Oil Blends
by Jun Cong Ge, Sam Ki Yoon and Jun Hee Song
Appl. Sci. 2021, 11(23), 11502; https://doi.org/10.3390/app112311502 - 04 Dec 2021
Cited by 6 | Viewed by 1404
Abstract
Vegetable oil as an alternative fuel for diesel engine has attracted much attention all over the world, and it is also expected to achieve the goal of global carbon neutrality in the future. Although the product after transesterification, biodiesel, can greatly reduce the [...] Read more.
Vegetable oil as an alternative fuel for diesel engine has attracted much attention all over the world, and it is also expected to achieve the goal of global carbon neutrality in the future. Although the product after transesterification, biodiesel, can greatly reduce the viscosity compared with vegetable oil, the high production cost is one of the reasons for restricting its extensive development. In addition, based on the current research on biodiesel in diesel engines, it has been almost thoroughly investigated. Therefore, in this study, crude palm oil (CPO) was directly used as an alternative fuel to be blended with commercial diesel. The combustion, engine performance and emissions were investigated on a 4-cylinder, turbocharged, common rail direct injection (CRDI) diesel engine fueled with different diesel-CPO blends according to various engine loads. The results show that adding CPO to diesel reduces the maximum in-cylinder pressure and maximum heat release rate to 30 Nm and 60 Nm. The most noteworthy finding is that the blend fuels reduce the emissions of hydrocarbons (HC), nitrogen oxides (NOx) and smoke, simultaneously. On the whole, diesel fuel blended with 30% CPO by volume is the best mixing ratio based on engine performance and emission characteristics. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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15 pages, 4137 KiB  
Article
The Future Impact of Carbon Tax on Electricity Flow between Great Britain and Its Neighbors until 2030
by Ahmad Rafiee, Mehdi Karimi, Amir Safari and Fahimeh Abbasi Talabari
Appl. Sci. 2021, 11(21), 10460; https://doi.org/10.3390/app112110460 - 07 Nov 2021
Cited by 2 | Viewed by 1549
Abstract
This paper investigates the future role of cross-border electricity flow between Great Britain (GB) and its neighbors until 2030, considering high deployment of renewable energy sources (e.g., wind, solar, and biomass), enhanced interconnection capacity, and a partly electrified heating sector. It was assumed [...] Read more.
This paper investigates the future role of cross-border electricity flow between Great Britain (GB) and its neighbors until 2030, considering high deployment of renewable energy sources (e.g., wind, solar, and biomass), enhanced interconnection capacity, and a partly electrified heating sector. It was assumed that two cross-border interconnectors links will connect GB’s power system to its neighbors: (1) a one-way interconnector (IC1) that imports electricity to GB, and (2) a two-way one (IC2) between France and GB. The IC2 was allowed to transfer electricity from a cheaper power system to a more expensive one. The results show that at a fixed CO2 price, a change in power imported via IC1 will affect the power dispatch of the CO2 emitting power plants and biomass-fired power plants, and electricity trade via IC1 and IC2. At IC1 importing of £60/MWh, by raising the CO2 price from 60 to £70/ton, the share of CCGT power plants will reduce by 75%, and the power imported via IC1 link will face 19-times growth. With a constant IC1 import price, raising the CO2 tax will reduce the total quantity of electricity being exported to France via IC2. Moreover, increasing the CO2 tax will increase the emissions cost of gas and coal-fired generators, and the power required to meet the demand will be imported via IC1. With the IC1 electricity price set to £20/MWh and the CO2 tax set to £50/ton, there may be 595 periods out of 17,520 in which GB will be used as an electricity trade corridor. GB’s total CO2 emissions should drop as the CO2 tax increases. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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21 pages, 2220 KiB  
Article
Optimization of Water Pressure of a Distribution Network within the Water–Energy Nexus
by Hossein Nasrollahi, Reza Safaei Boroujeni, Reza Shirmohammadi, Shima Najafi Nobar, Alireza Aslani, Majid Amidpour and Fontina Petrakopoulou
Appl. Sci. 2021, 11(18), 8371; https://doi.org/10.3390/app11188371 - 09 Sep 2021
Cited by 1 | Viewed by 2098
Abstract
Pressure control in water distribution networks (WDNs) reduces leaks and bursting. Thus, it is regarded as a valuable solution to cut costs related to the operation and maintenance of WDNs and it is recommended for use in deteriorated water distribution pipes. However, growing [...] Read more.
Pressure control in water distribution networks (WDNs) reduces leaks and bursting. Thus, it is regarded as a valuable solution to cut costs related to the operation and maintenance of WDNs and it is recommended for use in deteriorated water distribution pipes. However, growing consumer demand for satisfactory performance from faucets, combined with reduced water pressure from water supply companies, has resulted in an increased need for domestic water pressure booster systems (WPBSs) and has led to an increase in the energy demand. This misalignment of interests between water companies and energy consumers highlights the water–energy nexus perspective. This research aims to find a solution for optimizing the pressure of any WDN through the application of WPBSs to simultaneously minimize the cost associated with water leaks, repairs of burst pipes, and energy consumption. This methodology is applied to Baharestan city, where an optimum pressure of 47.6 mH2O is calculated. According to the sensitivity analysis of the inputs, the optimized pressure and cost are most sensitive to water loss and leakage exponent, respectively. Moreover, the hourly optimization of water pressure based on changes in demand and energy prices throughout the day is estimated to cut costs by 41%. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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14 pages, 1990 KiB  
Article
Optimization of the Electrical Demand of an Existing Building with Storage Management through Machine Learning Techniques
by Moisés Cordeiro-Costas, Daniel Villanueva and Pablo Eguía-Oller
Appl. Sci. 2021, 11(17), 7991; https://doi.org/10.3390/app11177991 - 29 Aug 2021
Cited by 5 | Viewed by 1867
Abstract
Accurate prediction from electricity demand models is helpful in controlling and optimizing building energy performance. The application of machine learning techniques to adjust the electrical consumption of buildings has been a growing trend in recent years. Battery management systems through the machine learning [...] Read more.
Accurate prediction from electricity demand models is helpful in controlling and optimizing building energy performance. The application of machine learning techniques to adjust the electrical consumption of buildings has been a growing trend in recent years. Battery management systems through the machine learning models allow a control of the supply, adapting the building demand to the possible changes that take place during the day, increasing the users’ comfort, and ensuring greenhouse gas emission reduction and an economic benefit. Thus, an intelligent system that defines whether the storage system should be charged according to the electrical needs of that moment and the prediction of the subsequent periods of time is defined. Favoring consumption in the building in periods when energy prices are cheaper or the renewable origin is preferable. The aim of this study was to obtain a building electrical energy demand model in order to be combined with storage devices with the purpose of reducing electricity expenses. Specifically, multilayer perceptron neural network models were applied, and the battery usage optimization is obtained through mathematical modelling. This approach was applied to a public office building located in Bangkok, Thailand. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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Review

Jump to: Research

27 pages, 4311 KiB  
Review
Recent Developments on Hydrogen Production Technologies: State-of-the-Art Review with a Focus on Green-Electrolysis
by Leonardo Vidas and Rui Castro
Appl. Sci. 2021, 11(23), 11363; https://doi.org/10.3390/app112311363 - 01 Dec 2021
Cited by 67 | Viewed by 13767
Abstract
Growing human activity has led to a critical rise in global energy consumption; since the current main sources of energy production are still fossil fuels, this is an industry linked to the generation of harmful byproducts that contribute to environmental deterioration and climate [...] Read more.
Growing human activity has led to a critical rise in global energy consumption; since the current main sources of energy production are still fossil fuels, this is an industry linked to the generation of harmful byproducts that contribute to environmental deterioration and climate change. One pivotal element with the potential to take over fossil fuels as a global energy vector is renewable hydrogen; but, for this to happen, reliable solutions must be developed for its carbon-free production. The objective of this study was to perform a comprehensive review on several hydrogen production technologies, mainly focusing on water splitting by green-electrolysis, integrated on hydrogen’s value chain. The review further deepened into three leading electrolysis methods, depending on the type of electrolyzer used—alkaline, proton-exchange membrane, and solid oxide—assessing their characteristics, advantages, and disadvantages. Based on the conclusions of this study, further developments in applications like the efficient production of renewable hydrogen will require the consideration of other types of electrolysis (like microbial cells), other sets of materials such as in anion-exchange membrane water electrolysis, and even the use of artificial intelligence and neural networks to help design, plan, and control the operation of these new types of systems. Full article
(This article belongs to the Special Issue 5th Anniversary of Energy Section—Recent Advances in Energy)
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