Special Issue "Renewable Energy Systems 2020"

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 (31 December 2020).
Related Special Issue: Renewable Energy Systems 2021

Special Issue Editor

Dr. Maria Vicidomini
E-Mail Website
Guest Editor
Department of Industrial Engineering, University of Naples Federico II, 80125 Naples, Italy
Interests: solar thermal systems; concentrating photovoltaic/thermal photovoltaic systems; energy saving in buildings; solar heating and cooling; solar desalination, geothermal energy; dynamic simulations of energy systems; renewable polygeneration systems
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Special Issue Information

Dear Colleagues,

In the last few years, several countries have experienced a dramatic increase in overall energy demand. Simultaneously, greenhouse gas emissions are increasing, leading to an increase of meteorological catastrophic events in several parts of the world. In this framework, several countries have agreed on the necessity to develop a novel sustainable energy paradigm and to perform all the actions required to limit the increase of the Earth’s average temperature. This goal can be achieved through different strategies: developing novel efficient energy conversion systems, promoting energy efficiency and a more conscious use of energy, and promoting the development of renewable energy sources. As a consequence, during the past few decades, a special effort has been made by several countries to develop novel and innovative energy systems, mainly based on renewable sources. This effort has led to a number of positive effects, such as energy diversification, reduction of pollutant emissions, and development of local green economies. On the other hand, the large non-programmable amount of renewable energy delivered to the electric grids poses severe issues in terms of management of excess energy and balance between demand and supply. This phenomenon is determining an increasing cost of the management of electric grids, which is typically transferred to the final consumer.

In this context, this Special Issue aims at collecting the most significant and recent studies dealing with the integration of renewable technologies into new or existing water, electricity, heating, and cooling networks. You are encouraged to submit manuscripts analyzing the possible utilization of renewables for multiple purposes (power production, heating, cooling, water management, transports), aiming at increasing the diffusion of such sources into our energy systems. Papers investigating novel electrical and thermal storage systems, as well as the adoption of electrical vehicles, are welcome, too. The topics of primary interest include but are not limited to:

  1. Energy planning
  2. Polygeneration systems based on renewables
  3. Advanced thermal storage
  4. Advanced electrical storage: compressed air energy storage (CAES), flying wheels, supercapacitors, etc.
  5. District heating and cooling systems
  6. Water pumping by renewables
  7. Thermally-driven water desalination
  8. Electrically-driven water desalination
  9. Integration of renewables with transportation, electrical vehicles
  10. System dynamic simulation
  11. Integration of renewable systems in buildings
  12. Control strategies and system management
  13. Economical assessment and funding policies
  14. Building dynamic simulation
Dr. Maria Vicidomini
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 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 2300 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.

Keywords

  • renewable energy systems
  • energy saving
  • electrical and thermal storage
  • simulation
  • energy–water nexus

Published Papers (11 papers)

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Editorial

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Editorial
Renewable Energy Systems 2020
Appl. Sci. 2021, 11(8), 3525; https://doi.org/10.3390/app11083525 - 15 Apr 2021
Viewed by 406
Abstract
In the last few years, several states have experienced a significant growth of the global energy demand [...] Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)

Research

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Article
Renewable Energy Tracking and Optimization in a Hybrid Electric Vehicle Charging Station
Appl. Sci. 2021, 11(1), 245; https://doi.org/10.3390/app11010245 - 29 Dec 2020
Cited by 3 | Viewed by 931
Abstract
The increasing electric vehicle fleet requires an upgrade and expansion of the available charging infrastructure. The uncontrolled charging cycles greatly affect the electric grid, and for this reason, renewable energy sources and battery storage are getting incorporated into a hybrid charging station solution. [...] Read more.
The increasing electric vehicle fleet requires an upgrade and expansion of the available charging infrastructure. The uncontrolled charging cycles greatly affect the electric grid, and for this reason, renewable energy sources and battery storage are getting incorporated into a hybrid charging station solution. Adding a renewable source and a battery to the charging station can help to “buffer” the power required from the grid, thus avoiding peaks and related grid constraints. To date, the origin of the energy coming from the battery has not been traced. In this paper, a solution of the hybrid electric vehicle charging station coupled with the small-scale photovoltaic system and battery energy storage is proposed to eliminate the adverse effects of uncontrolled electric vehicle charging, with the exact calculation of renewable energy share coming from energy stored in the battery. The methodology for the multicriteria optimization of the charging/discharging schedule of a battery and electric vehicle charging level is based on multi-attribute utility theory. The optimization criteria include the minimization of charging costs, maximization of renewable energy (from both the solar plant and the battery), and the minimization of battery degradation. The problem is solved using a genetic algorithm optimization procedure adapted to the multicriteria optimization function. The methodology is tested on an illustrative example, and it is proven that the decision-maker’s preferences greatly affects the choice of the optimal strategy and the optimal battery capacity. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
Appl. Sci. 2020, 10(23), 8443; https://doi.org/10.3390/app10238443 - 26 Nov 2020
Cited by 9 | Viewed by 851
Abstract
Power to gas (PtG) is an emerging technology that allows to overcome the issues due to the increasingly widespread use of intermittent renewable energy sources (IRES). Via water electrolysis, power surplus on the electric grid is converted into hydrogen or into synthetic natural [...] Read more.
Power to gas (PtG) is an emerging technology that allows to overcome the issues due to the increasingly widespread use of intermittent renewable energy sources (IRES). Via water electrolysis, power surplus on the electric grid is converted into hydrogen or into synthetic natural gas (SNG) that can be directly injected in the natural gas network for long-term energy storage. The core units of the Power to synthetic natural gas (PtSNG) plant are the electrolyzer and the methanation reactors where the renewable electrolytic hydrogen is converted to synthetic natural gas by adding carbon dioxide. A technical issue of the PtSNG plant is the different dynamics of the electrolysis unit and the methanation unit. The use of a hydrogen storage system can help to decouple these two subsystems and to manage the methanation unit for assuring long operation time and reducing the number of shutdowns. The purpose of this paper is to evaluate the energy storage potential and the technical feasibility of the PtSNG concept to store intermittent renewable sources. Therefore, different plant sizes (1, 3, and 6 MW) have been defined and investigated by varying the ratio between the renewable electric energy sent to the plant and the total electric energy generated by the renewable energy source (RES) facility based on a 12 MW wind farm. The analysis has been carried out by developing a thermochemical and electrochemical model and a dynamic model. The first allows to predict the plant performance in steady state. The second allows to forecast the annual performance and the operation time of the plant by implementing the control strategy of the storage unit. The annual overall efficiencies are in the range of 42–44% low heating value (LHV basis). The plant load factor, i.e., the ratio between the annual chemical energy of the produced SNG and the plant capacity, results equal to 60.0%, 46.5%, and 35.4% for 1, 3, and 6 MW PtSNG sizes, respectively. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
A Low-Cost Secure IoT Mechanism for Monitoring and Controlling Polygeneration Microgrids
Appl. Sci. 2020, 10(23), 8354; https://doi.org/10.3390/app10238354 - 24 Nov 2020
Cited by 2 | Viewed by 928
Abstract
The use of Internet-connected devices at homes has increased to monitor energy consumption. Furthermore, renewable energy sources have also increased, reducing electricity bills. However, the high cost of the equipment limits the use of these technologies. This paper presents a low-cost secured-distributed Internet [...] Read more.
The use of Internet-connected devices at homes has increased to monitor energy consumption. Furthermore, renewable energy sources have also increased, reducing electricity bills. However, the high cost of the equipment limits the use of these technologies. This paper presents a low-cost secured-distributed Internet of Things (IoT) system to monitor and control devices connected in a polygeneration microgrid, as a combined power system for local loads with renewable sources. The proposed mechanism includes a Wireless Sensor Actuator Networked Control System that links network nodes using the IEEE 802.15.4 standard. The Internet communication enables the monitor and control of devices using a mobile application to increase the efficiency. In addition, security mechanisms are implemented at several levels including the authentication, encryption, and decryption of the transmitted data. Furthermore, a firewall and a network intrusion detection-and-prevention program are implemented to increase the system protection against cyber-attack. The feasibility of the proposed solution was demonstrated using a DC microgrid test bench consisting of a diverse range of renewable energy sources and loads. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
A Game Theoretic Approach for Energy Sharing in the Italian Renewable Energy Communities
Appl. Sci. 2020, 10(22), 8166; https://doi.org/10.3390/app10228166 - 18 Nov 2020
Cited by 9 | Viewed by 1255
Abstract
With the Clean Energy Package, the European Union introduced the concept of Renewable Energy Communities: groups of citizens, small and medium enterprises and local authorities that decide to join forces to equip themselves with systems to produce and share energy from renewable energy [...] Read more.
With the Clean Energy Package, the European Union introduced the concept of Renewable Energy Communities: groups of citizens, small and medium enterprises and local authorities that decide to join forces to equip themselves with systems to produce and share energy from renewable energy sources. The Italian legislation recently started an experimental phase in which renewable energy communities receive an incentivising tariff for the energy produced and shared within the community. This paper faces the problem of creating a new renewable energy community in two steps. First, a mathematical model of the energy flows among the members of the community is characterised according to the Italian schema. This model is used to find the optimal portfolio for the energy community, given energy requests and local source availability. Secondly, the Shapley value, a particular solution of cooperative games known to be the most fair method to allocate costs and profits of shared infrastructures, is proposed to distribute benefits among community members. The methodology has been applied to a case study based on a real low voltage network, and the economics for consumers and producers in participating to the project have been evaluated. The proposed solution, simulated adopting real economic parameters defined in the Italian regulatory framework, results to be economically viable from the point of view of the investors with a profitability index of 1.36 and, at the same time, aligned with the social purposes of the energy communities. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
Droop Control Strategy of Utility-Scale Photovoltaic Systems Using Adaptive Dead Band
Appl. Sci. 2020, 10(22), 8032; https://doi.org/10.3390/app10228032 - 12 Nov 2020
Cited by 1 | Viewed by 599
Abstract
This paper proposes a novel droop control strategy for addressing the voltage problem against disturbance in a transmission system connected with a utility-scale photovoltaic. Typically, a voltage control at the renewable energy sources (RESs) connected to the transmission grid uses a reactive power–voltage [...] Read more.
This paper proposes a novel droop control strategy for addressing the voltage problem against disturbance in a transmission system connected with a utility-scale photovoltaic. Typically, a voltage control at the renewable energy sources (RESs) connected to the transmission grid uses a reactive power–voltage control scheme with a fixed dead band. However, this may cause some problems; thus, this paper proposes a method for setting a dead band value that varies with time. Here, a method for calculating an appropriate dead band that satisfies the voltage maintenance standard for two disturbances is described using voltage sensitivity analysis and the equation of existing droop control. Simulation studies are conducted using the PSS® E program to analyze the short term voltage stability and display the results for various dead bands. The proposed modeling and operational strategy are validated in simulation using a modified IEEE 39 bus system. The results provide useful information, indicating that the control scheme through an adaptive dead band enables more stable system operation than that through a fixed dead band. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
Modeling of a Village-Scale Multi-Energy System for the Integrated Supply of Electric and Thermal Energy
Appl. Sci. 2020, 10(21), 7445; https://doi.org/10.3390/app10217445 - 23 Oct 2020
Cited by 3 | Viewed by 1113
Abstract
Energy system models for off-grid systems usually tend to focus solely on the provision of electricity for powering simple appliances, thus neglecting more energy-intensive and critical needs, such as water heating. The adoption of a Multi-Energy System (MES) perspective would allow us not [...] Read more.
Energy system models for off-grid systems usually tend to focus solely on the provision of electricity for powering simple appliances, thus neglecting more energy-intensive and critical needs, such as water heating. The adoption of a Multi-Energy System (MES) perspective would allow us not only to provide comprehensive solutions addressing all types of energy demand, but also to exploit synergies between the electric and thermal sectors. To this end, we expand an existing open-source micro-grid optimization model with a complementary thermal model. Results show how the latter achieves optimal solutions that are otherwise restricted, allowing for a reduction in the Levelized Cost of Energy (LCOE) of 59% compared to a conventional microgrid, and an increase of reliance on renewable sources of 70%. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
Economic Assessment of Solar-Powered Residential Battery Energy Storage Systems: The Case of Madeira Island, Portugal
Appl. Sci. 2020, 10(20), 7366; https://doi.org/10.3390/app10207366 - 21 Oct 2020
Cited by 6 | Viewed by 954
Abstract
This paper presents an economic assessment of introducing solar-powered residential battery energy storage in the Madeira Island electric grid, where only micro-production for self-consumption is currently allowed. The evaluation was conducted against six local micro-producers using one year of energy consumption and solar [...] Read more.
This paper presents an economic assessment of introducing solar-powered residential battery energy storage in the Madeira Island electric grid, where only micro-production for self-consumption is currently allowed. The evaluation was conducted against six local micro-producers using one year of energy consumption and solar photovoltaic production measurements and two distinct storage control strategies. Several inverter sizes and storage capacities were considered based on the six micro-producers’ consumption and production profiles. The results were then analyzed concerning year-long simulations and a projection for the next ten years. To this end, several indicators were assessed, including self-consumption, profit per Euro invested, number of cycles and storage degradation. The results obtained show that, despite the benefits of storage to increase the self-consumption rates, considerable drops in the storage prices are still necessary to achieve profitability during these devices’ lifetime. Furthermore, our results also highlight a very interesting trade-off between self-consumption, pre-charge and profitability, in a sense that higher levels of pre-charge increase the chances of reaching profitability even though this will imply considerable drops in the levels of self-consumption. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
Assessment of the Impact of Electric Vehicles on the Design and Effectiveness of Electric Distribution Grid with Distributed Generation
Appl. Sci. 2020, 10(15), 5125; https://doi.org/10.3390/app10155125 - 26 Jul 2020
Cited by 4 | Viewed by 835
Abstract
The objective of this paper is to assess the probable effect that electric vehicles (EVs), already in wide circulation and likely to increase exponentially in the near future, will have on distribution networks. Analyses are conducted on the necessary interventions and evolutions that [...] Read more.
The objective of this paper is to assess the probable effect that electric vehicles (EVs), already in wide circulation and likely to increase exponentially in the near future, will have on distribution networks. Analyses are conducted on the necessary interventions and evolutions that the distribution grid will have to undergo in order to manage this new and progressively increasing heavy load of energy. Thus, in order to understand the technical limitations of the current infrastructure and how transformers and lines will be able to withstand the increasing penetration of EVs, urban and rural grid models have been studied, to highlight the differences between the impacts on high- and low-density networks. In addition, an analysis of fast charging station impact has been carried out. MATLAB software was used to perform the simulations for the creation of scripts, which were then exploited within the DIgSILENT PowerFactory software. This allowed evaluation of the networks under examination and verification of the effectiveness of the proposed solutions. In concluding based on findings, some methods of managing the distribution network to optimise the network parameters analysed in the study and a solution involving electric vehicles are recommended. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
Performance Evaluation of Two Machine Learning Techniques in Heating and Cooling Loads Forecasting of Residential Buildings
Appl. Sci. 2020, 10(11), 3829; https://doi.org/10.3390/app10113829 - 31 May 2020
Cited by 22 | Viewed by 1344
Abstract
Nowadays, since energy management of buildings contributes to the operation cost, many efforts are made to optimize the energy consumption of buildings. In addition, the most consumed energy in the buildings is assigned to the indoor heating and cooling comforts. In this regard, [...] Read more.
Nowadays, since energy management of buildings contributes to the operation cost, many efforts are made to optimize the energy consumption of buildings. In addition, the most consumed energy in the buildings is assigned to the indoor heating and cooling comforts. In this regard, this paper proposes a heating and cooling load forecasting methodology, which by taking this methodology into the account energy consumption of the buildings can be optimized. Multilayer perceptron (MLP) and support vector regression (SVR) for the heating and cooling load forecasting of residential buildings are employed. MLP and SVR are the applications of artificial neural networks and machine learning, respectively. These methods commonly are used for modeling and regression and produce a linear mapping between input and output variables. Proposed methods are taught using training data pertaining to the characteristics of each sample in the dataset. To apply the proposed methods, a simulated dataset will be used, in which the technical parameters of the building are used as input variables and heating and cooling loads are selected as output variables for each network. Finally, the simulation and numerical results illustrates the effectiveness of the proposed methodologies. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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Article
An Economic Analysis of An Innovative Floating Offshore Wind Platform Built with Concrete: The SATH® Platform
Appl. Sci. 2020, 10(11), 3678; https://doi.org/10.3390/app10113678 - 26 May 2020
Cited by 3 | Viewed by 931
Abstract
The goal of this work is to carry out an economic analysis of a novel floating offshore wind structure, of which the main material is concrete: the SATH® platform. It takes a step forward in floating marine wind energy research, in which [...] Read more.
The goal of this work is to carry out an economic analysis of a novel floating offshore wind structure, of which the main material is concrete: the SATH® platform. It takes a step forward in floating marine wind energy research, in which traditional platforms are mainly composed of steel. The technique to calculate the costs of the platform and the economic parameters to decide if the farm is economically feasible are explained in the paper. This case study analyzes a possible farm of 500 MW located in Portugal and several scenarios considering different electric tariffs and capital costs (Scenario 1: electric tariff of 50 €/MWh and 6% of capital cost; Scenario 2: electric tariff of 50 €/MWh and 8% of capital cost; Scenario 3: electric tariff of 150 €/MWh and 6% of capital cost; Scenario 4: electric tariff of 150 €/MWh and 8% of capital cost). Results show the economic feasibility of a farm with the characteristics of Scenarios 3 and 4. This work is significant in order to provide a new approach to analyzing traditional floating offshore wind structures, which can represent a path towards the future of floating offshore renewable energy technologies. Full article
(This article belongs to the Special Issue Renewable Energy Systems 2020)
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