Utilization Of Renewable Energy Resources Research Articles

Editorial: Emerging boost converter topologies for renewable energy applications

The role of the power electronic converter is very crucial for the effective utilization of renewable energy resources. Power electronic converters are used as an interface between the renewable energy source to the utilization which can be industrial loads, utility grids and domestic loads. The main converters used with the renewable energy resources are the DC/DC converter and DC/AC converter. As the voltage magnitude of most of the renewable energy resources is low, a boost stage is required between the source and the load. Therefore, a new category of high gain DC/DC converters and DC/AC converters are required with higher reliability and efficiency.The multilevel inverter (MLI) topology is a matured power converter and it is more suitable for medium and high voltage applications with renewable energy. Most of the multilevel inverters are employing isolated DC sources, which limits their applications. By replacing the DC source with capacitors, a significant reduction in the cost and size of the converters can be achieved. This The papers published in this special issue show the progress in the field of the power converter, and their control for various applications. Most of the concepts proposed in the articles have been validated experimentally. Still, there is a lot of scope for further improvement in the field of power converter and their control.

Recent technology and challenges of wind energy generation: A review

Energy is an integral part of economic growth and social development. Renewable energy sources are naturally occurring, which can help in reducing the dependency on non-renewable resources. The increasing effects of climate change have led to the utilization of renewable energy resources for power generation, among which wind is one of the significant sources of power generation. It provides a reliable, sustainable, and environmentally friendly alternative contributing to national energy security in the current age of decreasing global reserves of non-renewable resources across the globe. This paper reviews the wind energy technologies used, mainly focusing on the types of turbines used and their future scope. Further, the paper briefly discusses certain future wind generation technologies, namely airborne, offshore, smart rotors, multi-rotors, and other small wind turbine technologies. It also briefly discusses ways to improve the efficiency of different turbine generation technologies, majorly non-conventional ideas of wind turbine technologies based on cross axis wind turbine (CAWT), vertical axis wind turbine (VAWT), magnetic-based wind turbine. Overall, the summarization of wind energy here consists of four aspects: (1) wind turbine structure, (2) wind power generation technologies, (3) wind energy assessment methodologies, (4) limitation of developed technologies and future scope of wind energy development.

A Resource-Efficient Design for a Flexible Hydraulic-Pneumatic Flywheel in Wind Turbine Blades

The utilization of renewable energy resources significantly increases in order to reduce the impact of climate change. Wind turbines are one of the most important renewable energy sources and have an important role to play in power generation. They do, however, have to serve the increasingly variable demands of the grid. Some of these demands cannot be satisfied with the standard control mechanisms of state-of-the-art wind turbines. A hydraulic-pneumatic flywheel in a wind turbine rotor is one mechanism which, in addition to its various grid services, can also reduce the mechanical loads on the structure of a wind turbine. However, the installation of such a flywheel into rotor blades increases the weight of the blades. This paper focusses on the development of a design method for reducing the additional mass of the flywheel. This method incorporates the piston accumulators of the flywheel in the blade support structure, which allows for the replacement of parts of the blade spar caps with composite material from the piston accumulators. This enables the flywheel to be installed into the rotor blades without making the wind turbine significantly heavier.

Dual Battery Storage Technique for Remote, Location-Based Solar PV System and Standalone Applications

Nowadays, the usage of renewable energy resources (RER) is growing rapidly, but at the same time, the effective utilization of RER is also a challenging task. For the better usage of RER and the reduction of loss, the dual battery storage is proposed. The main aim of this work is to focus on the design and implementation of a reliable and renewable power generating system under a robust situation, along with a battery storage system. The perturb and observe (P&O) maximum power point tracking (MPPT) technique has been applied to improve the solar photovoltaic power production. In addition, the dual battery storage system is being introduced to improve the life cycle of the primary storage system. The proposed dual storage system is highly preferable for remote, location-based application systems, space applications and military operations. In the dual battery storage system, the batteries are working effectively with a good lifespan, when compared with the existing methods. To determine the state of charge (SOC) and depth of discharge (DOC), those batteries’ input charging and discharging levels were monitored closely. MATLAB Simulink (R2013) is used for simulation; finally, a real-time, three-phase inverter was designed and validated. Under this dual battery storage mode, the life time of battery is improved.

A review on various types of densification/briquetting technologies of biomass residues

The growing development, industrialization and population is the main reason of the increment in the global power demand around the world. The conventional power resources are limited and not eco-friendly as well as diminished in the future. Now, every country is move towards the more utilization of renewable energy resources. The biomass renewable energy source is one of them. The biomass residues material can be utilized for the production of power and also overcome the problem of decomposition of agricultural wastes and other wastes products by conversion into solid biomass fuels. The conversion of scattered agricultural residues/wastes into the useful product (biomass fuel) through the technology known as densification. The densification process supports the more utilization of renewable source and clean energy demands. The environmental challenges related with burning of biomass residues in the open field can be minimized by the densification of biomass residues. The densification is the process of compaction or densifying the biomass residues or waste through the application of various pressure levels. The challenges associated with handling, storage and transportation of biomass residues can also be minimize by densification technology. Briquettes and pellets are the end product of densification applications. The various types of densification pressure application and comparison have been discussed in the paper.

The Necessity of Sustainable Development and Climate Systems to Protect Natural Resources and Human Race

Sustainable development ensures a well-managed utilization of natural resources for the present generation along with preserving it for future usage. Increased rate of population and urbanization is found as major challenging factors in respect of practicing sustainable development activities. Both aforementioned problems are also prevalent in India that disrupts the attainment of Sustainable Development Goals. However, the Government of India has taken suitable initiatives to promote utilization of renewable energy resources by means of International Solar Alliance, Green India Mission, and others. Technological inclusion in this regard would be beneficial in implementing such programmes in an optimum way. Consequently it would ensure preservation of natural assets for future usage and maintain the quality of climatic conditions in a suitable way. Keyword :Sustainable development, climatic conduction, natural resources, human civilization

Intelligent ensemble of voting based solid fuel classification model for energy harvesting from agricultural residues

In recent times, utilization of renewable energy resources for transportation and electric power generation can be the sustainable way that reduces the risk of environmental, climatic, economic, political, and security concerns related to fossil fuel combustion. Among the several renewable energy sources, biomass is commonly used due to the fulfilment of ecological compatibility due to the fact that it is attained from plant and animal waste.At the same time, the classification of fuel materials becomes difficult when the material is previously processed or gathered from an environment that makes it challenging to discern. Therefore, with the constant development and diversification of energy harvesting from agricultural residues, there is a requirement to design a model for the classification of solid fuels. The recent developments of machine learning (ML) and deep learning (DL) techniques can be used for the solid fuel classification. The ML and DL models comprise many interdisciplinary areas, such as statistics, mathematics, artificial neural networks, data mining, optimization, and artificial intelligence. With this motivation, this paper designs a new intelligent ensemble of voting based solid fuel classification (IEVB-SFC) model for energy harvesting from agricultural residue. The proposed IEVB-SFC technique involves different stages of operations such as data acquisition, data preprocessing, classification, and ensemble process. At the primary stage, the data preprocessing is carried out in three different ways such as data transformation, class labeling, and data normalization. Besides, the IEVB-SFC technique comprises three different DL models as long short term memory (LSTM), gated recurrent unit (GRU), and convolutional neural network based LSTM (CNN-LSTM). Finally, an ensemble of three DL models takes place by the use of voting technique and thereby determines the appropriate solid fuel class labels, show the novelty of the work. The experimental results showcased the betterment of the IEVB-SFC technique over the recent state of art techniques with the maximum accuracy of 0.97.

Multilayer thin-film based nanophotonic windows: static versus electrotunable design

To meet the global energy demand, rapid growth in fossil fuel consumption has significantly contributed to global warming. Judicious utilization of renewable energy resources could help to combat this global challenge. Here, we present a comparative study on the designs of static and electro-tunable ‘smart’ windows that could help to reduce the energy need of typical air-conditioning systems deployed in buildings and motor vehicles. Our design comprises insulator–metal–insulator multi-layered thin-films deposited over a silica glass substrate to filter visible and infrared solar radiation selectively. For static windows, we optimize our design to operate in diverse climatic conditions by choosing different combinations and thicknesses of metal and insulator layers. Whereas for electro-tunable windows, we use an electro–optic polymer as the insulator layers to dynamically control portions of transmitted solar radiation over a voltage range of −12 to +12 V. Through size-dependence analysis, we could safely assume that the performance of smart windows is less likely to degrade during experimental realization. Our designs are lithography-free, large-area compatible, polarization-independent, angle-insensitive, and robust to fabrication imperfections. The analytical results show a near-perfect match with the simulation findings. The theoretically calculated figure of merit indicates that our proposed smart windows can outperform industry-standard commercial windows.

Optimal Dispatch of Multi-Energy Integrated Micro-Energy Grid: A Model Predictive Control Method

In order to reduce the impacts caused by large-scale renewable energy resources accessing the utility grid, the micro-energy grid system, as a natural extension of the microgrid in the energy internet era, is proposed and developed to provide a new solution for the optimal utilization of renewable energy resources. In this paper, a multi-energy integrated micro-energy system is proposed which contains wind, PV, bedrock energy storage, magnetic levitation electric refrigeration, solid oxide fuel cell, solar thermal collector, energy storage, and V2G technologies, and detailed models of the energy generation/conversion/storage devices are formulated. Besides this, the uncertainties of renewable energy resources and cold/heat/electricity loads are considered, and the optimal dispatch problem of the micro-energy system is established from day-ahead and real-time time scales based on a model predictive control method. The day-ahead optimal scheduling aims at economic optimization and guides real-time scheduling, and real-time scheduling utilizes rolling optimization and a feedback correction mechanism to effectively correct the deviation of renewable energy generations and loads at a real-time horizon, which improves the optimization control accuracy, follows the day-ahead dispatch plan, and ensures the economics of real-time scheduling at the same time.

Design and application of a distributed generation hosting capacity algorithm

Distribution networks in Southern Africa and elsewhere are witnessing an unprecedented growth of consumer-side distributed generation (DG) courtesy of governmental interventions to maximise the utilisation of renewable energy resources through low-carbon grid-edge technologies. To deal with the increasing adoption of consumer-side DG, distribution network operators need to conduct technical studies to foster an understanding of the benefits and impacts of DG and the hosting capacity (HC) of existing distribution networks. This will aid the implementation of measures to manage grid exports. Using a distribution network in Namibia as a case study, this paper presents an algorithm for assessing the HC of consumer-side DG in existing distribution networks that are situated in areas anticipating high and uniform uptake of DG. The algorithm is a hybrid of deterministic and probabilistic methods. The uniqueness of the algorithm is the concept of calculating monthly HC. The algorithm was tested on a real existing residential distribution network and the results confirmed that HC varies monthly. However, the practical implementation of monthly HC requires upgrades to existing inverter technology, which currently contains a single export limit functionality. This opens the possibility to drive innovation in the inverter technology to develop a date-based multiple export limit functionality.

A scalable and reconfigurable hybrid AC/DC microgrid clustering architecture with decentralized control for coordinated operation

Microgrid clusters are effective to increase utilization of renewable energy resources (RESs), and improve reliability and stability of power systems. Facilitating flexible configurations, grid networking and coordinated operation among multiple microgrids are essential for the microgrid cluster. In view of this, this paper presents a scalable and reconfigurable hybrid microgrid clustering architecture and a corresponding decentralized control method. Initially, a new interlinking converter referred as energy networking unit (ENU) is proposed. The ENU is used to interface the AC and DC subgrid in single hybrid microgrid, and also facilitates the connection with the external power grid. Then the ENU-based hybrid microgrid clustering architecture is established, which is characterized by scalability, reconfigurability and modularity. Thanks to the reconfigurable topology of ENUs, the architecture could realize flexible AC/DC interconnection between microgrids by the same converter modules with less power conversion units. Finally, a proposed decentralized control strategy for this architecture could realize autonomous power exchange between subgrids in single microgrid with considering energy storage restrictions and smooth mode switch. And an adaptive and autonomous power interaction among neighboring microgrids is also achieved with full utilization of the compensation capacity of clusters, thus improving the system reliability, as well as the utilization and local consumption of RESs. The effectiveness of the proposed clustering architecture and decentralized control strategy is verified by comprehensive cases.

Artificial intelligence on economic evaluation of energy efficiency and renewable energy technologies

The energy sector currently faces growing challenges related to increasing demand, efficiency, a lack of analytics required for optimal management, and changing supply and demand patterns. Renewable energy technologies such as Energy forecasting, energy efficiency, and energy accessibility are the key factors that incorporate Artificial intelligence. In this paper, the Artificial Intelligence-based useful evaluation model (AIEM) has been proposed for forecasting renewable energy and energy efficiency impact on the economy. This study intended to analyze, compare and build a model utilizing artificial intelligence and specific economic indicators significant in economic prediction regarding renewable energy. AI approaches that can be employed to overcome different challenges, including selecting the best consumer to react for the attributes and desires, competitive pricing, scheduling, and managing facilities, incentivizing demand responseparticipants, and compensating them equally and economically. The proposed model can help enhance energy efficiency to 97.32% and improve renewable energy resource utilization.

Decentralized energy management for unbalanced networked microgrids with uncertainty

The energy management schemes in microgrids enhance the utilization of renewable energy resources and improve the reliability and resilience measures in the distribution networks. While microgrids operate autonomously, the coordination among microgrid and distribution network operators (DNOs) contributes to the improvement in the economics and reliability of serving the demand. Here, a decentralized energy management framework for the networked microgrids is proposed in which the interactions between the microgrid and DNOs are captured using the Benders decomposition technique. The proposed framework limits the information shared among these autonomous operators and facilitates decentralized energy management in the distribution networks. Furthermore, the unbalanced operation of the distribution network and microgrids, as well as the uncertainty in the operating modes of the microgrids, renewable energy resources, and demand, were addressed. Modified IEEE-34 bus and IEEE-123 bus distribution networks are used to validate the effectiveness of the proposed algorithm.

Proposal and thermo-economic optimization of using LNG cold exergy for compressor inlet cooling in an integrated biomass fueled triple combined power cycle

Utilization of renewable energy resources and efficiency improvement of energy conversion systems are of great importance due to energy crisis and environmental issues. Renewable energy driven Triple Combined Cycle (TCC) is a relatively new idea in this respect. In this paper, a biomass gasification-fueled TCC is presented in which the conventional gas turbine, as the topping cycle, is combined with a Closed Brayton Cycle (CBC) and an Organic Rankine Cycle (ORC). The proposed TCC is integrated with LNG regasification process to exploit its cold exergy for compressor inlet cooling of the CBC. For the CBC three working fluids (namely: helium, nitrogen and carbon dioxide) are considered. There is a good thermal match between the LNG and these fluids in heat rejection process and they can be cooled down to temperatures of below 0°C at the compressor inlet for net power augmentation. Thermoeconomic method is applied to evaluate the TCC performance and optimization using genetic algorithm is employed to minimize the Levelized Cost of Electricity (LCOE). In the economic analysis the cost rate of environmental impacts due to pollutant emissions is also considered. The results indicated the superiority of helium over the other investigated working fluids from the economic perspective for which the LCOE is found to be 51.38 $/MWh. However, as an interesting outcome it is found that, from thermodynamic standpoint using CO2 as the working fluid yields higher exergy efficiency by 6.7% than the helium.

Analysis of efficiency enhancement of flat plate solar collector using crystal nano-cellulose (CNC) nanofluids

The upward energy demand, along with the depletion of conventional energy sources, demands improved utilization of renewable energy resources. Among all renewable energy resources, solar energy is the most appropriate alternative to conventional energy sources owing to its inexhaustibility and green property. Solar collectors are devices that convert solar radiation into heat or energy. However, the efficiency of the solar collector is still not adequate. The competent step to enhance the efficiency of the solar collector is to use nanofluids. This study is carried out different phases viz. characterization and stabilization while both qualitative and quantitative methods used to evaluate the stability of nanofluids thermophysical properties of Al2O3 and CNC nanofluids such as thermal conductivity measured at four different temperature using KD2 Pro, viscosity and specific heat determined at similar temperature range by viscometer and differential scanning calorimetry respectively. The experiment is executed with a fixed flow rate and in steady-state conditions under extensive solar radiation. The experimental study has revealed that up to 2.48% and 8.46% efficiency of solar collector enhanced by using 0.5% Al2O3 and 0.5% CNC nanofluids respectively. Moreover, nanofluids show good to moderate stability performance. Besides, the thermal conductivity of nanofluids increased while viscosity is in a decreasing trend with increasing temperature. Nanofluids could enhance the efficiency of a flat-plate solar collector.

Design and Development of a Proficient Converter for Solar Photovoltaic Based Sustainable Power Generating System

The demand for renewable energy resources is invigorated due to various issues primarily related to energy security, energy sustainability, and greenhouse gas emissions. The proper utilization of renewable energy resources has certain challenges due to the varying nature of meteorological parameters and atmospheric aerosols. Therefore, it is of utmost importance to extract the maximum power from the photovoltaic systems with the help of proficient converters. Here, a coupled inductor based highly efficient synchronous interleaved boost converter is designed and developed for the grid integrated photovoltaic system. The proposed converter contains an Insulated Gate Bipolar Transistor (IGBT) switch in place of the conventional diode to maintain zero leakage current, bared minimum switching losses, and improved conduction time thereby enhancing the overall efficiency and reliability of the system. In addition, the proposed system topology is simple to implement and is capable of controlling power at both the generation as well as the load sides. The results obtained are validated with the help of a laboratory prototype under practical scenarios like varying temperature and solar irradiance. Further, an intelligent technique based on modified particle swarm optimization is utilized to extract the maximum power from the photovoltaic system. Moreover, the power quality indices were monitored and analyzed at the point of common coupling and at the grid level which vets the effectiveness of the proposed topology.

Prospect of green power generation as a solution to energy crisis in Bangladesh

Non renewable energy sources in Bangladesh is severely limited. Mainly in the rural areas energy crisis and desertification problem is very acute. Thus, it is essential to find out the renewable energy resources as well as to improve the effective renewable energy technologies. Bangladesh is adorned with huge renewable energy capitals such as solar, hydro, wind, biomass, tidal and geothermal energy due to its appropriate geographical position. Proper harnessing of these renewable energy sources would be a promising solution to alleviate the energy need mainly in the rural areas of Bangladesh. However, there are some political, economical, technological, informational, institutional, personnel barriers for proper utilization of renewable energy resources. It is required to work together of different government and non-government organizations to solve the problems and utilize the renewable energy technologies. Thus, renewable energy technology development related research works are crucial in developing countries like Bangladesh. Moreover, the potentiality of renewable energy capitals and their implementation is needed to be assembled in details to understand the whole scenario of the renewable energy sector of Bangladesh. The objective of this research is to deliver a recent review of renewable energy status in Bangladesh in respect to the energy potentiality and its implementation, research and development activities. Major challenges of the renewable energy sector of Bangladesh are also addressed and based on that some recommendations are provided.

PV-Diesel-Hydrogen fuel cell based grid connected configurations for an institutional building using BWM framework and cost optimization algorithm

The concept of Demand Side Management (DSM) is a popular topic in power system that provides an opportunity for grid operators to improve power grid’s stability and efficiency. However, most of the DSM techniques does not consider user satisfaction. This work uses the load data collected from a department in an institution located in Southern India based on user satisfaction to manage the load through peak shifting strategy in DSM technique. The load pattern before and after DSM implementation is supplied in an economical way through the utilization of renewable energy resources along with the existing grid connection. Optimization analysis is performed with the help of Hybrid Optimization of Multiple Energy Resources (HOMER) simulation software for a different combination which includes PV with grid, PV-Diesel with grid and PV-Hydrogen fuel with grid. Of the various results obtained from simulation, the best configuration is selected based on Multi-Criteria Decision Analysis (MCDA). The Best-Worst Method (BWM) under MCDA is used to select the best configuration based on various criteria. The results shows that the configuration of solar PV with grid after DSM (0.961 preference) holds the highest preference followed by the combined configuration of solar PV and diesel power with grid after DSM (0.792 preference) and lastly by the combined configuration of solar PV and hydrogen fuel cells with grid before DSM (0.425 preference). This work also develops an approach for cost optimisation, and it is capable of giving maximum satisfaction to the user based on the preferred user-budget which is another key finding of this work. Three different budget scenarios are considered, for which the load pattern generated reveals that maximum satisfaction is attained by the user for the predetermined user budgets.

Energy Management Strategy for Grid-Networks of a Distributed Generation

Energy management and control are major factors of importance in this revolutionary era of power system. The revolution in renewable energy generation and its utilization imposes to develop and adopt energy management strategies. Considering the dynamic behavior of renewable energy sources and load, a systematic control and energy management strategy is developed. The aim of this paper is to implement real time supervision and energy management on a hybrid system for efficient utilization of renewable energy resources. The developed energy management strategy can be imposed on any size of off-grid and on-grid distributed renewable energy generation system. A grid connected distributed generation is considered with solar, wind and biomass energy sources with battery as a storage. MATLAB is used to develop energy management strategy and different cases are resulted successfully. The effectiveness of energy management strategy on hybrid system and its results are presented and discussed.

A Modified Hybrid DC Circuit Breaker With Reduced Arc for Low Voltage DC Grids

The increasing demand for the development and utilization of renewable energy resources has lead to a growing interest in the development of LVDC systems. The dc grid provides more flexibility in integrating different forms of renewable energy sources effectively. However, the lack of a reliable protection mechanism remains the main drawback in the growth of dc distribution systems. Unlike ac systems, the absence of a natural zero crossing in dc systems for arc extinction makes the use of a conventional mechanical circuit breaker (MCB) a less reliable solution. The use of a solid-state circuit breaker (SSCB) results in fast fault interruption but reduces the overall efficiency of the system due to the on-state voltage drop of the semiconductor devices. A hybrid circuit breaker (HCB) combining MCB and SSCB yields better static and dynamic performances but the main challenges remains in the demagnetization of the transmission line inductance after a fault interruption and an arc formation between the MCB contacts. This paper proposes a hybrid circuit breaker (HCB) which is suitable for fast fault interruption in low voltage dc (LVDC) systems while alleviating the above issues. Proposed topology employs a semiconductor switch as well as an actively switched capacitor branch in parallel with the main mechanical breaker to facilitate fast current commutation during a fault. The mechanical breaker forming the main branch is turned off at zero voltage. This eliminates the arc formation across the moving contacts of the breaker. Moreover, the fault interruption process does not require a varistor for network demagnetization following the fault current commutation. This paper also presents a discharging mechanism for the capacitor in a practical implementation. Operation of the proposed dc circuit breaker is evaluated through a prototype tested in the laboratory.