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Electrical energy becomes necessary for human being. Generation of electrical energy mostly depends on fossils fuel, they are limited in nature and also responsible for environmental pollution. Renewable energy resources provides a better alternative for future,In comparison to conventional energy resources economical aspect is a major issue of renewable energy sources with the feasibility and efficiency. These limitations are tried to overcome by deployment hybrid renewable energy resources. There are certain criteria to analyze and implement the sized, optimized and cost efficient system. This paper focus on hybrid energy systems based on solar photovoltaic (PV) and wind resources. This paper shed lights on various parameters of economic feasibility, sizing strategies with logical advancements to enhance their utilization, future prospects, and their arrangement. Strategies to develop an effective storage system is also presented here.A brief review on developments in optimization techniques, reliability index and cost analyzing techniques for hybrid renewable energy systems are also presented. [ABSTRACT FROM AUTHOR]

Abstract: Photovoltaic (PV) generation of electricity is an important renewable energy source. One way to increase the value of small-scale renewable generators is to aggregate and control their output so they appear to the wider grid as one larger generator. This paper introduces our Virtual Power Station system which aggregates multiple geographically dispersed small-scale photovoltaic generators together to present to the wider electricity system as a single dispatchable quantity in an energy market. As such a quantity has greater benefit to the wider system than the individual responses of many uncoordinated energy sites, the Virtual Power Station can improve the payback period for renewable energy systems. This paper describes a Virtual Power Station deployment with a diverse range of sites, and PV output, which are then coordinated together with an intelligent battery controller. We also introduce an optimal control strategy that manages the energy storage to allow a firm commitment of output energy from the Virtual Power Station. [Copyright &y& Elsevier]

• Solar photovoltaics stored by using cheap and abundant materials. • The Calcium-Looping process is integrated as electricity stored system (40% efficiency) • Electric-to-electric performance of the whole system reaches 57%. • A notable cost reduction could be achieved as alternative to batteries. Solar photovoltaic plants are today a competitive alternative to power plants based on fossil fuels. Cost reduction in photovoltaics modules, scalability and ease of installation of these plants are enabling a rapid worldwide expansion of the technology. Nevertheless, dispatchability still remains as the major challenge to overcome due the intrinsic variability of solar energy. Most of the current solar photovoltaic facilities at large scale lack energy storage while those with storage systems rely on expensive batteries. Batteries are based on elements such as nickel, lithium or cadmium whose scarcity hinder their sustainability for storing energy in the large scale. This manuscript presents a novel concept to integrate thermochemical energy storage in photovoltaic plants. Furthermore, the concept is also directly adaptable to wind power plants to store surplus energy. The paper analyses the suitability of the Calcium-Looping process as thermochemical energy storage system in solar photovoltaics plants. The system works as follows: part of the power produced in the solar plant provides electricity to the grid while the rest is used to supply heat for calcination of calcium carbonate. After calcination, the products of the reaction – calcium oxide and carbon dioxide- are stored separately. When power production is required, the stored products are brought together in a carbonation reactor wherein the exothermic reaction releases energy for power production. The overall system is simulated to estimate the process behaviour and results show that storage efficiencies of ∼40% can be achieved. Moreover, an economic analysis is developed to compare the proposed system with batteries. Due to the low price of natural calcium oxide precursors, such as limestone, and the expected longer lifetime of equipment as compared to batteries, the Calcium-Looping process can be considered as a potential alternative for improving dispatchability in solar photovoltaic plants. [ABSTRACT FROM AUTHOR]

This paper considers the technical and economic feasibility of using renewable energy with hydrogen as the energy storage medium for two remote communities in Bhutan, selected to illustrate two common scenarios presenting different challenges. The Royal Government of Bhutan has published plans to provide electricity to all households in the next 20 years, but the practical problems of extending the grid over long distances and mountainous terrain will make that target difficult and expensive to achieve. Consequently, the possibility of using natural energy and diversified generation is attractive. This paper examines the use of hydro power in one community and photovoltaics with wind power in another. Hydrogen is the proposed energy storage medium in both cases. Analysis suggests that it is technically possible to use renewable energy and hydrogen for diversified power supplies and that where, as here, the costs of grid extension are high, it may also be financially viable. Thus we argue that there is a good case for establishing a test and demonstration system near the capital Thimphu for further investigation prior to use in remote locations. [Copyright &y& Elsevier]

The work presented in this paper deals with an assisted management of a standalone multi-source power system. The proposed structure consists of a wind turbine (WT) and a photovoltaic generator (PV) used as renewable sources, a super-capacitor (SC) as an energy storage system and a diesel generator (DG) as an emergency power supply. The aim of this work was to develop an assisted management strategy in order to control the power flow in the system operation with the highest reliability. Four limits of the SC state of charge (SOC) were defined states for the power control strategy. The main advantage of the used strategy was to protect the storage system from the deep charge and discharge and then increase its lifespan. The proposed energy management concept was tested in simulation by applying all possible cases. The obtained results confirm its efficiency and harmony between production and consumption was guaranteed. [ABSTRACT FROM AUTHOR]

• Hydrogen storage systems enable flexible energy conversion and scheduling. • Hydrogen storage cost accounts for the largest proportion of system cost. • The hydrogen energy storage system has less demand for energy storage space. With global energy consumption increasing year by year, the industrial sectors of the world's countries have never been more urgent in achieving carbon reduction. Renewable energy plays a crucial role in the industrial decarbonization process. As the most mature renewable energy technology, wind and photovoltaic power generation have made significant progress in recent years. However, the intermittent characteristics hinder the efficient use of renewable energy. Existing research provides sufficient support for the flexible scheduling of large-scale renewable energy. Hence, this paper proposes a combined energy system composed of wind power-photovoltaic-energy storage salt cavern with hydrogen as the energy scheduling carrier. The system mainly realizes energy conversion through electrolytic water equipment and fuel cells. Then, Qianjiang City, Hubei Province, is taken as the analysis object, and the working conditions of each component in the system are optimized with the help of an improved particle swarm optimization algorithm. According to the results, the system's contribution to the energy system is discussed, and the system's economy and carbon reduction effect is studied. The analysis proves that the improved particle swarm optimization algorithm has a stronger solving ability. The combined energy system can effectively improve the economy and renewable energy utilization rate, meet the regional electricity demand, and significantly reduce carbon emissions. The economic analysis of the system shows that the operation and maintenance cost of hydrogen storage salt caverns accounts for the largest proportion of the total cost, about 60 %. Compared with several existing large-scale energy storage technologies, it is found that the energy efficiency of the whole system is only about 40 % due to the limitation of technology maturity. Nevertheless, the flexibility of the hydrogen storage system layout is relatively high. The required underground space volume is only equivalent to 1/6 and 1/2 of pumped storage and compressed air storage with the same scheduling capacity. The system will provide a theoretical support for the optimization of energy pattern and layout. [ABSTRACT FROM AUTHOR]

Hydrogen is seen as the future energy that will help decarbonise the emissions of global energy use. Hydrogen-related technologies have recently attracted considerable attention due to their relatively low emissions and high energy yield. Even then, little attention was given to hydrogen's use in energy distribution networks. A renewable-based multi-energy system (RMES) considers power, cooling, heating, and hydrogen energy as utility systems for integrated urban and industrial areas to achieve urban-industrial symbiosis. This paper formulates the RMES as a multi-period mixed-integer nonlinear programming (MINLP) model to optimise the RMES, which minimises the financial implications and environmental impacts. Renewable solar energy is provided to the system using the photovoltaic solar system for electrical generation and the solar thermal collector for heat generation. Thermal, battery and hydrogen energy storages are integrated into the RMES to mitigate the energy supply and demand fluctuations and intermittency. A comparative analysis is conducted to individually identify the performance of different energy storage systems for economic and environmental objective functions. The comparison findings indicate that ESS performs better with 45% usage increases under objective environmental functions. The multi-objective optimisation using the ϵ-constraint method obtains the Pareto optimal solutions to the proposed multi-objective problem, which the 4th solution (ATC: 782,500 USD/y; ACE: 2,777.03 kg CO 2 -eq/y) appears to be the most viable. The solution maintains a high-profit level without sacrificing many opportunities for carbon emissions reduction while satisfying both objective functions simultaneously to a degree of satisfaction of 0.75. Overall, the proposed RMES is proven economical and environmentally friendly for implementation; however, the model is needed to optimise the system based on the specific situation. This study provides the optimisation model for energy recovery and technology optimisation in the multi-energy system for urban-industrial symbiosis, which minimises carbon emission and energy cost. This could lead the energy sector to achieve the Sustainable Development Goals, considering the economically and environmentally viable. • Renewable-based multi-energy system for urban-industrial symbiosis. • Heating, electricity, cooling and hydrogen energy demands are considered. • Multi-period optimisation based on economic and environmental factors. • Thermochemical, battery and hydrogen storages are compared. • Multi-objective optimisation for obtaining the non-dominating Pareto optimal. [ABSTRACT FROM AUTHOR]

Recently, energy management systems (EMSs) and storage equipment have become increasingly important for optimizing operating schedules to reduce operating costs. Although many previous studies aimed to optimize the operating schedule of energy systems, some considered only perfect predictions for demand and photovoltaic (PV) power generation. In practice, however, predicted values are often different from actual phenomena. Thus, a practical method that can specify how to control each component under the uncertainty is needed. In this paper, we proposed a new optimization strategy to handle the uncertainty and called it the two-time steps recalculation strategy (TtsR). TtsR proposes a framework for problem formulation and functions in combination with an optimization method. Epsilon differential evolution (εDE) was adopted to handle efficiency nonlinear and constraint conditions. TtsR was compared to the all-time steps recalculation strategy (AtsR), which is considered an ideal strategy because it can obtain accurate solutions. The results showed that TtsR required lower computational time than AtsR to obtain a quasi-optimal solution under conditions of unpredicted changes in the power generation and demand; meanwhile, TtsR was able to maintain computational accuracy. [ABSTRACT FROM AUTHOR]

One of the main advantages of solar photovoltaic (PV) energy is its availability during periods of high electricity demand, namely hot, sunny days. Unfortunately, the daily energy peak of a south-facing solar panel, oriented to maximize energy production, rarely coincides with the actual peak in electricity demand, which is usually in the late afternoon or evening. Using the Province of Ontario, Canada, as a case study, this paper evaluates three strategies for improving the correlation between PV energy production and electricity demand: optimally orienting PV modules, combining geographically dispersed arrays, and using a simple energy storage system. The strategies are compared based on their ability to improve the supply-demand correlation, their relative cost of energy, and the capacity credit of each strategy. We find that optimally orienting multiple modules in an array offers little potential to improve correlation, while the cost of energy increases between 30 and 40%. Geographically dispersed PV arrays and energy storage offer a better approach to improving the correlation between PV production and electricity demand. [ABSTRACT FROM AUTHOR]

Abstract: The large band variation in the wind speed and unpredictable solar radiation causes remarkable fluctuations of output power in offshore wind and photovoltaic system respectively, which leads to large deviation in the system frequency. In this context, to minimize the deviation in frequency, this paper presents integration of different energy resources like offshore wind, photovoltaic (PV), fuel cell (FC) and diesel engine generator (DEG) along with the energy storage elements like flywheel energy storage system (FESS) and battery energy storage system (BESS). Further ultracapacitor (UC) as an alternative energy storage element and proportional–integral (PI) controller is addressed in order to achieve improvements in the deviation of frequency profiles. A comparative assessment of frequency deviation for different hybrid systems is also carried out in the presence of high-voltage direct current (HVDC) link and high-voltage alternating current (HVAC) line. Frequency deviation for different isolated hybrid systems are presented graphically as well as in terms of integral square error (ISE). Both qualitative and quantitative analysis reflects the improvements in frequency deviation profiles with use of ultracapacitor (UC) as energy storage element. [ABSTRACT FROM AUTHOR]

Abstract: PEPITE is a project funded by the French ANR PAN-H research program. This project concerns, among various other tasks, a demonstration of a weather station electricity supply with help of a PV/FC/EL hybrid system located at the CEA center of Cadarache (France). To design a relevant sizing for this demonstration system, a complete sizing tool has been developed via a new numerical optimizing code named ORIENTE. It uses Matlab software based on sequential running time. The demonstration system will be composed of a PV array, a PEM fuel cell system and a PEM electrolyzer, batteries, storage tanks for H2, O2 and H2O, as well as associated converters. This paper presents the obtained optimal sizing curves for the hybrid system (Ppv [kWp], [kg]) by taking into account the predefined constant load (6.5kW) functioning 24/24hours and the system energy balance for a loss-of-load probability LLP=0. These results give the sizes of each subsystem and will make possible to build the best energy flows control mode. [Copyright &y& Elsevier]

Abstract: A stand-alone renewable-energy system employing a hydrogen-based energy store is now being commissioned within the HaRI project at West Beacon Farm, Leicestershire, UK. The interconnection of the various generators, loads and storage system is made through a central DC busbar: an arrangement that is believed to be unique within systems of this type and scale. The rotating generators, such as the wind turbines, are connected through standard industrial drives operating in regenerative mode, while the DC devices—electrolyser, fuel cell and solar photovoltaic array—employ custom DC–DC converters. This paper reviews the design philosophy of the electrical system and the various converters required. Modelling and simulation of the system is discussed along with practical lessons learnt from its implementation and some initial results are presented. [Copyright &y& Elsevier]

• A robust optimization model is proposed to handle economic dispatch problems with uncertainties. • An improved distributed approach with self-adaptive step-size and a polynomial filter is proposed. • It has faster convergence performances and robustness to random communication failures. Power systems are confronted with prodigious challenges of scheduling and operation incurred by the high penetration of distributed renewable energy with intermittency and uncertainty. Therefore, this paper proposes an improved distributed robust optimization approach with self-adaptive step-sizes based on the line search method and a polynomial filter, to minimize the overall costs of flexible resources including conventional generators, energy storage systems, renewable energy curtailments, deferrable loads and tie-line power exchanges, while considering various constraints, such as supply-demand power balance, line congestion constraints and power output limits. Numerical case studies conducted in a modified IEEE 14-bus system and a modified IEEE 118-bus system demonstrate the reliability, robustness and extensibility of the proposed approach. In addition, the effectiveness and accuracy of the proposed distributed robust optimization approach are validated through comparisons with the traditional centralized gradient method and the convergence performance is better in contrast to other distributed optimization algorithm. [ABSTRACT FROM AUTHOR]