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Overview on recent developments in energy storage: Mechanical, electrochemical and hydrogen technologies

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... ESS can also support system balancing, economic dispatching on the bulk transmission system, and regulation of power quality and coordination of distributed energy resources on distribution systems [2e4]. Small scale ESSs are used today in local communities or behind the meter to improve the emergency preparedness and resiliency of the grid [5]. The deployment of ESS technologies, alongside with other solutions such as advanced control systems and energy managment systems, can enhance the grid's capabilities and resiliency [1]. ...
... Among the most challenging design requirements for pumped hydro that limit its future growth is the availability of suitable geological sites to store the compressed water [7,8]. Compressed air is another relatively mature ESS technology, but is limited to the regions with suitable geological structures to store large amounts of compressed air [5]. Some new rechargeable battery technologies such as redox flow and zinciron batteries are promising ESS technologies, but still have some limitations that slow their deployment such as their high initial cost and low energy [5,8]. ...
... Compressed air is another relatively mature ESS technology, but is limited to the regions with suitable geological structures to store large amounts of compressed air [5]. Some new rechargeable battery technologies such as redox flow and zinciron batteries are promising ESS technologies, but still have some limitations that slow their deployment such as their high initial cost and low energy [5,8]. Other rechargeable battery technologies such as lead-acid, sodium-sulfur, and lithium-ion (Li-ion) batteries can be used as ESS, but they lack some characteristics of the efficient ESS systems. ...
Article
The intermittent nature of power generated by renewable energy systems makes it harder for many power grids to accommodate large generations in short period of times. In this paper, we quantify and discuss the cost associated with storing excess energy from the wholesale electricity markets in the United States in the form of hydrogen using proton exchange membrane reversible fuel cells (PEM-RFC) and in the form of electrochemical energy stored in lithium-ion batteries (LIB). The key financial metric used in this study is the levelized cost of electricity storage (LCOS). Results show that electricity can be stored in many regions in the U.S. at very competitive costs, reaching as low as 16.6¢/kWh using RFC and 8.6¢/kWh using LIB using electricity purchased from California Independent System Operator (CAISO). These values are near the future targets set by the U.S. Department of Energy of 5¢/kWh. Sensitivity analysis revealed that the LCOS using both ESSs is dependent on the following design and financial parameters from higher to lower effect: ESS roundtrip efficiency, system capital cost and the expected system lifetime, respectively. Analysis of system performance and economics showed that LIB seem to have better economic advantage based on the LCOS values, but lack the flexibility of the RFC system. RFC, on the other hand, has more advantages in terms of the size of energy storage capacity, operational charging/discharging flexibility, and the effect on increasing the grid resiliency, especially during long periods of power outages.
... Different storage systems exhibit different discharge times: short discharge time (less than 1 h) characterize flywheels and supercapacitors, small-scale compressed air energy storage (CAES) and batteries have medium discharge time (up to 10 h), pumped hydro storage (PHS) and large-scale CAES have a discharge time that is usually greater than 10 h. [6]  Efficiency It must be considered that an energy storage has an efficiency ( ), that can be defined as the ratio of the energy that is absorbed by the system (in), and the energy that is supplied by the system (out). = = (4) Efficiency propagates, so if there are several processes in series, the efficiency of the whole system is calculated as the product of all the efficiencies relative to the processes involved, as shown in Eq. (5). ...
... However, these devices are also very susceptible to self-discharge, and cannot operate at high voltages. [5] Fig. 6: Comparison of different electrochemical storage systems. [12] 1. 3 ...
Thesis
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This thesis work describes the research activity regarding a personal cooling system with integrated PCM (phase change material). The experimental analyzes were carried out in the ENEA research center in Portici. The system under consideration has the purpose of creating personal cooling, or localized cooling (for example, for a workstation inside an office). Such a system, characterized by low power, is generally coupled to a centralized air conditioning system. As demonstrated by multiple studies, if such a system is present, it allows for better conditions of comfort within the occupied spaces and to raise the set point temperature of the centralized system, allowing for significant energy savings. The system is based on the use of a phase change material inside the condenser of a vapor compression system, which absorbs the heat released from the refrigerant fluid during the condensation, thus allowing for the creation of a portable system with a high storage capacity, without the need to exchange heat with the external environment during the operation of the system. The development of a numerical model to be able to simulate the system in question is of fundamental importance, since, in general, a numerical model allows to design, analyze, and optimize a system without the need to carry out multiple onerous experimental tests. It is also evident that there is a need to have a valid model, so having experimental data with which to compare and therefore validate the results of the simulations is essential. This thesis work is divided in two different sections: in the first section, an introduction on the topics of energy storage, phase change materials, personal cooling, numerical modeling techniques is presented. The second section presents the implemented model and the experimental setup that has been realized, as well as the results of the experimental tests and numerical simulations.
... For this reason, recently, the excellent complementarity with PSPs promotes IRESs to be combined with hydro-equipment [8]. Nevertheless, the widely implemented fixed-speed pumped storage plants (FSPSPs) cannot regulate power flows under pumping operations due to their rigid operating characteristics [17,18]. In this case, the pumping system cannot continuously afford the duty of mitigating the power variation which may extremely influence the reliability of the [19][20][21][22][23] due to its several advantages compared to traditional FSPSPs where these advantages include the rapidity, high efficiency, and reliability in operation and regulation [24]. ...
... The mechanical power Pm can be described in Eq. (17) P m = ηρgqh. (17) A linearized pump-turbine model with six coefficients is generally applied to describe the pump-turbine characteristics [24,32], as shown in Eq. (18) { T m = e my y + e mω ω r + e mh h q = e qy y + e qω ω r + e qh h ...
Article
The integration of hydropower and variable energy sources emerges as a functional method for handling power variability. Due to the advantage of adjustable power input of the pumped storage operation, variable-speed pumped storage plants (VSPSPs) have been proposed as a potential alternative to traditional fixed-speed pumped storage plants (FSPSPs) for dealing with the variable storage demand. The performance evaluation of VSPSPs in coping with changes in loads and variations in renewable energy sources during the energy storage process is crucial to ensure adequate flexibility and reliability of the grid. In this paper, the regulation performance assessment of VSPSP in mitigating wind power variations is presented based on IEEE 14-bus test system. The goal is to draw up the regulation reliability of the VSPSP under pumping mode for balancing the dynamic characteristics of wind power. Specifically, a numerical model of VSPSPs with doubly-fed induction machines is described and developed which is then validated by the measured data in the form of a case study. Moreover, by considering ten wind scenarios having differences in frequency, gradient, guts intensity, and standard deviation; simulations of VSPSP performing power regulation in the pump mode are conducted and the dynamic regulation effects are assessed. Finally, the power regulation quality comparison is provided between the power generation and storage modes to validate the regulation reliability of the VSPSP under the pumped storage operation. The regulation time delay (RTD) ratios of VSUs to FSUs are found in the range of 4.67–9.16%, demonstrating the rapidity of VSPSPs in the power regulation.
... Lead-acid and nickel-cadmium batteries are the most mature solutions; however, the majority of the current research and development is focusing on lithium-ions batteries. The latter can offer a relatively high lifetime, though approximatively four times lower than PHS, elevated round-trip efficiencies, about 75 to 97 % [30], and very high energy densities, around 75 to 200 Wh/kg [32]. However, they have high upfront costs limiting their market growth and economic potential for large scale applications [33]. ...
... TCi j  , defined as in Eq. (32). These values enable to understand where the modeling error is mostly located. ...
Thesis
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High-temperature thermal energy storage could enable widespread exploitation of renewable energy sources, providing the required energy flexibility. Technology and component development is needed to enhance the storage thermo-dynamic performance, and identify key design features. Similarly, system-level integration studies are required to fully understand the techno-economic potential of high-temperature thermal energy storage as integrated into different energy systems. This research work focuses on the development of an innovative packed bed high-temperature thermal energy storage and a multi-level investigation of the potential of this technology. The integration and techno-economic performance of a packed bed thermal energy storage have been studied focusing primarily on its application within concentrating solar power plants. Numerical studies and experimental tests have been conducted assessing the suitability of various coatings to optimize the heat transfer in high-temperature packed beds. A comprehensive design of an innovative packed bed thermal energy storage prototype and its experimental evaluation have been presented. Adapted numerical models have also been validated based on the experimental results, providing the ground for further technology development.The outcomes of this research work show that packed bed thermal energy storage could be a key component in air-driven concentrating solar powerplants, granting high capacity factor while limiting the capital costs. The designed radial flow packed bed storage showed thermal efficiency of about72 % and extremely low-pressure drops. Thermocline degradation control strategies and proper packing have been highlighted as key aspects to target for further development. This research also highlights that accurate boundary conditions should be accounted for when designing packed bed thermal energy storage. Innovative figures of merit, such as the Levelized Cost ofStorage, should be included in the design process. The outcomes of this work show also that coatings could be exploited to modify the particle surface properties while optimizing the heat transfer within packed bed units. In particular, high emissivity coatings could enhance the effective thermal conductivity, while coatings with low thermal emissivity could be exploited as a form of passive thermocline control. Finally, this work testifies that high temperature packed bed could represent a techno-economically valuable energy storage solution. Optimized packed bed designs and their system integration could enable higher renewable penetration, as well as the recovery of a large amount of waste heat from the hard-to-abate and energy-intensive industrial sector.
... A large number of research efforts deal with the ESS technologies utility and potential in meeting the challenges linked to unpredictable renewable energy sources fluctuations [23][24][25][26]. In [23][24][25][26], the current research, the development, characteristics, functionalities, and the application potential of ESS technologies are presented. ...
... A large number of research efforts deal with the ESS technologies utility and potential in meeting the challenges linked to unpredictable renewable energy sources fluctuations [23][24][25][26]. In [23][24][25][26], the current research, the development, characteristics, functionalities, and the application potential of ESS technologies are presented. Accordingly, mechanical, electrochemical, hydrogen, thermal and electrical technologies can be interesting to reinforce the quality and the stability of the grid in presence of renewable energy sources. ...
Article
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The issues of variability and uncertainty of tidal speed result in severe challenges for standalone microgrid (as island grids for examples) operators. Indeed, to maintain the system power balance, existing classical generators which are associated with tidal power units must be able to frequently change their operating point, either up or down, to respond to the fast fluctuations of tidal power and consumption and sometimes exceed their maximal ramp capability. This in turn accelerates aging process and results in serious damage. The switching to a safer and more reliable system seems to be a promising and long-term solution. This paper proposes to associate a supercapacitor-based Energy Storage System (SC-ESS) to a tidal turbine to smooth the fast power production fluctuations. The association of this SC-ESS with the tidal turbine unit aims to meet requirements on the variation of injected tidal power in an islanded microgrid. An original smart power management strategy is proposed for the use of the ESS. Taking into account this strategy, an optimal design methodology based on simulations on the more severe encountered day cases is proposed. This methodology allows to determine a minimal sizing of the ESS to fulfil the grid requirements. The paper also proposes a complete modeling of the whole system behavior. The Energetic Macroscopic Representation (EMR) tool is used to realize the system model where the inversion-based control principle is then used to deduce the control schemes. This global methodology is applied to a test tidal turbine which is based on a real 1MW prototype setup to the islanded grid of Ushant in France. Using real measured data, it is shown that a relatively small and low cost SCs pack is sufficient to accommodate the high tidal power fluctuations. A comparison is performed between the existing configuration where a resistor bank is used to shave the excessive power variation and the considered case where SCs pack is used. For one tidal cycle, it is shown that a reduction in energy loss of 18.2% is achieved, which presents a non-negligible gain for Ushant’s Island microgrid.
... In prepIn collaboration with our Italian partners it was possible to improve the discharge capacity performance of HPIE using hematite dispersed over high surface carbon black, the difference is that this dispersion resulted from the synthesis process of the material, which lead to an improved discharge capacity performance.Renewable sources such as solar, wind, tidal and wave are mostly stochastic and are characterised by their intermittency and variability over time. Because of this, it is not possible to ensure that the power generation will coincide with the load demand unless it is coupled with a suitable energy storage technology[9,10]. ...
Thesis
Novel energy storage technologies are required to further the development of crucial applications to reduce the dependence on fossil fuels. In particular for electric propulsion and for the efficient utilization of intermittent sources of renewable energy. Metal-air-batteries are appealing candidates to develop these type of energy-storage-technologies due to their theoretical energy-density. In particular the iron-air-battery (IAB) with a theoretical energy-density of 764 W h kg<sup>-1</sup> , represents a low cost, environmentally friendly alternative. During the 70s, research into the IAB system was performed and a few laboratory prototypes were developed. Unfortunately, the specific energy density and cell potential of these prototypes were far below their theoretical value due to challenges in their engineering design and electrochemistry performance. Recently, the study of IABs has been of special interest to the automotive industry, due to the possibility of rechargeable metal-air batteries for electric vehicles. Furthermore, the new technological advances in nanomaterials since the 70s, and the use of new catalyst materials in combination with innovative laboratory tools for the manufacturing of the electrodes have enabled IAB s to achieve a further level of development. The main research goal of this Ph.D. research has been to determine the electrochemical performance of a novel IAB using novel nanostructured materials reported in the literature and to gain insight of what are the advantages and main challenges of this electrochemical system. The applied methodology included to develop and optimise each one of its components, mainly the negative iron-electrode, and the positive bifunctional-gas diffusion-electrode. The detailed study of the iron-electrode lead to the comparison of various reported active-iron-materials including: carbonyl iron, hematite, goethite, magnetite and iron sulphide as active-materials in hot-pressed-ironelectrodes, this research lead to the development of iron-electrodes with capacities as high as 910 m A g<sup>-1</sup> <sub>Fe</sub> using Fe<sub>2</sub>O<sub>3</sub>/C, and mean discharge capacities of 650 m A g <sup>-1</sup> <sub>Fe</sub> over 240 hrs of continuous reduction-oxidation cycling at the C/5 rate (254.6 mA g<sup>-1</sup> <sub>Fe</sub>). Research on the air electrode lead to the development of a gas diffusion electrode with a remarkably stability able to cycle up to 3000 cycles continuously and to perform at current densities up to 1000 mA cm<sup>-2</sup> before deteriorating. Furthermore, the comparison of Ni-Fe hex-cyanoferrate, palladium and LSFCO perovskite on carbon as bifunctional catalysts and its combination lead to the development of optimised gas diffusion electrodes. In parallel the development as a proof of concept of an IAB stack and a larger scale IAB (200cm<sup>2</sup> GDE electrodes) required the engineering design of various IAB prototypes which were manufactured using 3D printing techniques that allowed rapid modifications and improvements before an optimised prototype was sent to be manufactured using traditional computer numerical control machining. The electrochemical testing of these batteries prototypes are as well part of the main results of this research. Finally, the electrochemical performance of a novel iron air battery prototype with an energy density as high as 453 W h kg<sup>-1</sup> <sub>Fe</sub> and a maximum capacity of 814 mA h g <sup>-1</sup> <sub>Fe</sub> when cycled at a current density of 10 mA cm<sup>-2</sup> equivalent to 100 mA g<sup>-1</sup> <sub>Fe</sub>, achieving a power density of ca. 75 W kg<sup>-1</sup> <sub>Fe</sub> was achieved.<br/
... The energy demand of the world is increasing day by day and the most commonly used energy sources are still fossil fuels [1,2]. Alternative energy sources have been sought, to overcome the adverse outcomes of the use of fossil fuels, such as global warming [3,4]. ...
Article
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Perovskites are well-known oxides for thermochemical energy storage applications (TCES) since they show a great potential for spontaneous O2 release due to their non-stoichiometry. Transition-metal-based perovskites are particularly promising candidates for TCES owing to their different oxidation states. It is important to test the thermal behavior of the perovskites for TCES applications; however, the amount of sample that can be used in thermal analyses is limited. The use of redox cycles in fluidized bed tests can offer a more realistic approach, since a larger amount of sample can be used to test the cyclic behavior of the perovskites. In this study, the oxygen release/consumption behavior of Mn- or Cu-substituted SrFeO3 (SrFe0.5M0.5O3; M: Mn or Cu) under redox cycling was investigated via thermal analysis and fluidized bed tests. The reaction enthalpies of the perovskites were also calculated via differential scanning calorimetry (DSC). Cu substitution in SrFeO3 increased the performance significantly for both cyclic stability and oxygen release/uptake capacity. Mn substitution also increased the cyclic stability; however, the presence of Mn as a substitute for Fe did not improve the oxygen release/uptake performance of the perovskite.
... The AC type, on the other hand, necessitates more data, such as reactive power and frequency synchronization, making the control computing step more difficult. Aside from that, DC microgrids can operate in a variety of modes, including AC microgrid, stand-alone, and integrated with AC (Amirante et al., 2017;Ma et al., 2017). ...
Article
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With increasing energy prices, nuclear energy concerns, climate changes, and electrical grid losses, the demand to rely on more renewable energy is growing. The majority of people currently prefer to live and work in smart environments, such as smart cities and smart institutions with an integrated smart microgrid. Energy management is a complex topic because a large amount of these smart microgrid systems rely on hybrid energy sources. As a result, a smart energy management controller needs to be created. The current research provides a new energy management control technique for a smart DC-microgrid based on a combined fuzzy logic controller (FLC) and high order sliding mode (HSMC) methods. The hybrid energy provider integrated into the DC-microgrid is made up of a battery bank, wind energy, photovoltaic (PV) energy, and tidal energy source. The new proposed intelligent control is intended to regulate source-side converters (SSCs) in order to capture the maximum energy from hybrid renewable energy sources (wind, tidal and PV) while also improving power quality in the DC-microgrid. To keep the microgrid as cost-effective as feasible, renewable energy sources are prioritized. The suggested controller offers a steady output power and sustained service. From the present simulation results under Matlab/Simulink and the comparative analysis, the proposed controller produces +1.02% wind power, +10% PV power, +100% tidal power, and +8.48% load power over intelligent fractional-order proportional-integral-derivative (PID) and more when compared to the super twisting fractional-order and PID controls. In addition, the suggested controller assures smooth output power and uninterrupted service.
... 65 On the other hand, storage in hydrogen is characterized by negligible self-discharging losses, but lower values of overall round-trip efficiency (mostly due to the losses incurred during hydrogen production and re-electrification), making it more suited to seasonal energy storage. 66,67 Furthermore, electricity storage in hydrogen is likely to use large-scale hydrogen production (e.g., electrolysers) and conversion (e.g., fuel cells) plants, making power-to-hydrogen costcompetitive with respect to batteries. The cost of the expensive components of a power-to-hydrogen system, electrolysers and fuel cells, scale with the rate of the charging/discharging power conversion processes (instead of the stored energy quantity). ...
Article
The envisioned role of hydrogen in the energy transition – or the concept of hydrogen economy – has varied through the years. While in the past hydrogen was mainly considered...
... In the event of increased energy demand or higher prices, the stored water can be used for the production of additional energy. Conversely, if the demand is reduced and the energy prices are low, water can be accumulated and stored for use at a more appropriate time (Amirante et al., 2017). Compressed-Air Energy Storage (CAES) is an energy storage system based on air compression and storage in underground geological reservoirs (usually salt caverns). ...
Article
The choice of the energy storage technology involves multiple criteria that need to be simultaneously considered in the energy planning process. The development of sustainable energy system requires to take into account not only technical characteristics of storage technologies but also to pursue sustainability issues. The paper aims to perform not-site-specific sustainability assessment of the main types of energy storage technologies (mechanical, chemical, electrochemical and thermal) based on the developed advanced multi-criteria technique. The paper follows the vein of the coordinated Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and extends it to the interval environment. A geometric integer programming model is introduced to identify the interval for the degree of coordination. The proposed method is, therefore, able to handle uncertainty and coordinate performance of the alternatives with respect to multiple criteria. Sustainability assessment of energy storage technologies is performed based on the most important technological, economic, environmental and social criteria. The results showed that the most sustainable energy storage technologies are mechanical and thermal ones (utility scores range in between 1 and 0.75). The remaining technologies exhibit utility scores of 0.69 at most. The least appealing options are electrochemical storage technologies.
... In this research, a numerical study is utilised to examine the behaviour of the backed-bed medium during a seven-day performance analysis of the overall system. NPP can be directly coupled with TES unit as solar power plants (Alva et al., 2018;Amirante et al., 2017;Atif and Al-Sulaiman, 2018;Pelay et al., 2017;Prieto and Cabeza, 2019;Xu et al., 2015). This alternative is found to be a promising option to follow the variations in the electric power demand profiles and needs more investigations (Denholm et al., 2012;Forsberg et al., 2018;Forsberg and Peterson, 2016). ...
Article
An innovative thermal energy storage (TES)-nuclear power plant (NPP) coupled system is investigated. This system is intended to have a better ability to follow the grid demand. In this design, the phase change material (PCM)-based TES have a dual role in acting as a simple heat exchanger during optimal operation, or energy storage/supplier to overcome the fluctuating energy demand. To assess the coupling feasibility, the efficiency of overall system is examined using energy and exergy balances at different components for two designs of the power generation process: Rankine and supercritical carbon dioxide (SCO2) Brayton cycles. Results confirm that around 50% of the exergy is lost during plant operation in the reactor core. Most importantly, the losses in the TES are much smaller (<10%) than the reactor core losses. Advanced (SCO2) Brayton cycle is more efficient than Rankine cycle and efficiency can reach 50% using high effectiveness and high-efficient components.
... These technologies have merits, challenges and different levels of technological maturity with many already proven for the commercial-scale application. Hence, the optimal energy storage system depends on sets of factors including geography, geopolitical, socioeconomic, resources, renewable energy technologies, cost-effectiveness and a mix of capacities and operation modes (Aneke and Wang 2016;Amirante et al. 2017). Despite this, the pumped hydro energy storage has been used in the ETRB for decades (Johnson 2016), the topography limitations and the increase of water stress in the basin imposed the need for new distributed energy generation and storage in different scale of capacities as well as national scale of economy energy storage system in the riparian countries region. ...
Chapter
Understanding the interdependency of energy and water and the influencing factors as well as how this interrelation impacts the other essential sectors for the riparian states in the Euphrates and Tigris river basin. A literature review was conducted on the water stress, dispute and the renewable energy resources available in the basin. The water usage in the energy sector and the energy consumption in the water sector are reviewed. Nexus thinking and stakeholders’ engagement approach were discussed to mitigate the water dispute in the basin. The asymmetry in power with the resources diversity in the riparian countries was promoted as an entry point for more collaboration and joint actions. The renewable energy resources availability was reviewed incomparable to the status of the renewable energy sources utilised, that already exist or are planned in the basin.
... La classification est généralement réalisée en fonction de la forme sous laquelle est stockée l'énergie électrique. La figure III.2 présente une classification des SSE réalisée à partir de plusieurs références [201,202,203,204,205,103]. Parmi les SSE, les systèmes électrochimiques et chimiques permettent de stocker l'énergie électrique sous forme d'énergie chimique puis de la restituer en convertissant l'énergie chimique en électricité. ...
... Non-GIES is a common type of ESS that converts primary energy directly into electricity for storage. Meanwhile, Amirante et al. [123] made an overview of the three types of ESS: ...
Article
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Seaports are well known as the medium that has evolved into the central link between sea and land for complex marine activities. The growth in maritime logistics particularly necessitates a large volume of energy supply in order to maintain the operation of sea trade, resulting in an imbalance between generation and demand sides. Future projections for three major concerns show an increase in load demand, cost of operation, and environmental issues. In order to overcome these problems, integrating microgrids as an innovative technology in the seaport power system appears to be a vital strategy. It is believed that microgrids enhance seaport operation by providing sustainable, environmentally friendly, and cost-effective energy. Although microgrids are well established and widely used in a variety of operations on land, their incorporation into the seaport is still limited. The involvement of a variety of heavy loads such as all-electric ships, cranes, cold ironing, and buildings infrastructure renders it a complicated arrangement task in several aspects, which necessitates further research and leaves space for improvement. In this paper, an overview of the seaport microgrids in terms of their concepts and operation management is presented. It provides the perspectives for integrating the microgrid concept into a seaport from both shore side and seaside as a smart initiative for the green port’s vision. Future research directions are discussed towards the development of a more efficient marine power system.
... However, most studies in Chile have focused on the viability of green H 2 production [18,30,34,[38][39][40]. However, the main problem in this value chain is storage [41][42][43][44][45] since it must be defined very carefully according to the conditions of each application. ...
Article
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The paper presents a complete value chain for the use of green hydrogen in a port facility. The main objective was to propose the sizing of the main components that make up green hydrogen to ensure the supply of 1 MWe in replacing the diesel generator. The energy demand required for the port was determined by establishing the leading small and large-scale conventional energy-consuming equipment. Hence, 60 kgH2 was required to ensure the power supply. The total electrical energy to produce all the hydrogen was generated from photovoltaic solar energy, considering three-generation scenarios (minimum, maximum and the annual average). In all cases, the energy supply in the electrolyzer was 3.08 MWe. In addition, the effect of generating in the port facility using a diesel generator and a fuel cell was compared. The cost of 1 kgH2 could be 4.09 times higher than the cost of 1 L of diesel, meaning that the output kWh of each system is economically similar. In addition, the value of electrical energy through a Power Purchase Agreement (PPA) was a maximum of 79.79 times the value of a liter of diesel. Finally, the Levelized Cost of Energy (LCOE) was calculated for two conditions in which the MWe was obtained from the fuel cell without and with the photovoltaic solar plant.
Article
In this study, the hydrogen storage capacity of the graphene oxide layer was studied electrochemically. The graphene oxide was synthesized by modified Hummers' method and applied on the nickel foam by electrophoretic deposition (EPD) method at different potentials (20 and 60 V) and times (20 and 60 min) to determine the effect of applied potential and time of deposition on the hydrogen adsorption performance. The hydrogen adsorption tests including charge-discharge test, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were conducted in 6 M KOH solution and at room temperature. Based on the achieved CV curves, the graphene oxide (GO) layer achieved at 60 V within 20 min has a higher electrochemical hydrogen adsorption capability compared to other obtained samples. The calculated hydrogen storage capacity is obtained 50.9 mA. h. g⁻¹. The rosette flower like morphology of the obtained GO layers at optimum condition, has an impressive effect on the improving electrochemical hydrogen adsorption based on morphology study by field emission scanning electron microscopy.
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Zinc-based redox flow batteries (ZRFBs) have been considered as ones of the most promising large-scale energy storage technologies owing to their low cost, high safety, and environmental friendliness. However, their commercial application is still hindered by a few key problems. First, the hydrogen evolution and zinc dendrite formation cause poor cycling life, of which needs to ameliorated or overcome by finding suitable anolytes. Second, the stability and energy density of catholytes are unsatisfactory due to oxidation, corrosion, and low electrolyte concentration. Meanwhile, highly catalytic electrode materials remain to be explored and the ion selectivity and cost efficiency of membrane materials demands further improvement. In this review, we summarize different types of ZRFBs according to their electrolyte environments including ZRFBs using neutral, acidic, and alkaline electrolytes, then highlight the advances of key materials including electrode and membrane materials for ZRFBs, and finally discuss the challenges and perspectives for the future development of high-performance ZRFBs.
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Attempts to utilize lithium-ion batteries (LIBs) in large-scale electrochemical energy storage systems have achieved initial success, and solid-state LIBs using metallic lithium as the anode have also been well developed. However, the sharply increased demands/costs and the limited reserves of the two most important metal elements (Li & Co) for LIBs have raised concerns about future development. Sodium-ion batteries (SIBs) equipped with advanced cobalt-free cathodes show great potential in solving both "lithium panic" and "cobalt panic", and have made remarkable progress in recent years. In this review, we comprehensively summarize the recent advances of high-performance cobalt-free cathode materials for advanced SIBs, systematically analyze the conflicts of structural/electrochemical stability with intrinsic insufficiencies of cobalt-free cathode materials, and extensively discuss the strategies of constructing stable cobalt-free cathode materials by making full use of non-cobalt transition-metal elements and suitable crystal structures, all of which aim to provide insights into the key factors (e.g., phase transformation, particle cracks, crystal defects, lattice distortion, lattice oxygen oxidation, morphology, transition-metal migration/dissolution, and the synergistic effects of composite structures) that can determine the stability of cobalt-free cathode materials, provide guidelines for future research, and stimulate more interest on constructing high-performance cobalt-free cathode materials.
Article
With a rapid growth of Integrated Energy System (IES) in various scenarios, researches on IES have attracted extensive attention in the last few decades. Inspired by the ever-increasing studies about the IES, which focus on various energy scenarios but lack a systematic summarization, this paper aims to undertake a comprehensive review of the IES models, operation optimization methods, and model tools. Firstly, CiteSpace is used to visually analyze the cooperation and co-occurrence network of related articles in recent two decades, among which 1998 papers from WOS are selected for analyzing. Note that 243 papers highly related to IES are further investigated to systematically analyze and integrate the relevant work. On this basis, different definitions of IES around the world and 12 related research hotspots are summarized. Then, the IES modeling methods are creatively classified from eight aspects. Furthermore, from the perspective of operation optimization methods, three mainly optimal problems, including Economic Dispatch, Unit Commitment and Optimal Power Flow, are comprehensively analyzed. Besides, 22 energy model tools are discussed from the levels of National, Regional, and Users. Finally, seven advantages and three challenges are summarized, four key points are concluded, and six perspectives/recommendations are proposed for future research. In general, this paper is intended to offer an insightful guidance to prompt related researchers/engineers to broaden the horizons of their researches.
Article
Frequent condition changes of pumped storage hydropower system make it inclined to stuck in extreme energy conversion process, posing great threats to steady operation. This paper proposes a comprehensive framework to specify optimal operation strategy for admirable transient process under extreme conditions. Three principles consist the framework, the refined model of successive load rejection is primarily established, which accedes time-varying and strong nonlinear characteristics and accurately grasps the trait of successive load rejection. Furthermore, an improved genetic algorithm with excellent capabilities of exploration and exploitation is proposed, multiple control schemes are investigated with variations of control parameters. Whereafter, a hierarchical decision-making structure of operation strategy considering qualitative and quantitative indicators is firstly constructed, the intuitionistic fuzzy analytic hierarchy process is innovatively introduced to specify optimal scheme. The originality of the framework lies in comprehensiveness and completeness. Multiple complexities of refined model, multiple schemes of optimization strategy, multiple determinants of decision-making are fully considered. Testifying to real cases, the optimal strategy can effectively improve water pressure indicators of volute and draft tube by at most 64.4 m and 32.52 m. These results highlight the effectiveness and availability of the proposed framework for sustaining safe operation simultaneously reducing investments of pumped storage hydropower systems.
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In order to satisfy future demands, renewable energy sources (RESs) need to be integrated into the power system due to the fast use and pollution of fossil fuels. Solar energy, geothermal energy, ocean energy, wind energy, bioenergy, and other RESs have been deployed in many locations around the world, particularly in rural areas [1,2]. The most common RESs are wind and solar energy. Small-scale off-grid (microgrid) systems are established in remote locations rather than establishing transmission lines to transfer power from generation units to loads. A micro-grid system is a tiny system that mostly uses solar and wind energy. Increased nonrenewable energy supplies and storage of energy have also increased in order to guarantee the permanent and stable power supply due to instability, intermission, and the high cost of solar and wind power systems. Hybrid renewable energy systems are created when RESs are combined with other energy sources [3,4]. The demand for energy by consumers is generally not evenly distributed over time and problems of the phasing of energy produced versus energy consumed arise. The stability of the grid depends on the balance between production and consumption [3]. The increase in the penetration rate of renewable energies.
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It is widely common for distribution network operators to impose restrictions on delivered solar photovoltaic (PV) generated power when the power-plant-rated power is greater than the maximum allowed power due to the distribution network capacity. Thus a feasible solution to maximize the performance of the solar power plant is the integration of battery energy storage systems (BESS). Although this configuration has been extensively studied in the existing literature, an optimal design method to determine the proper size and operation of the energy storage system needs to be developed. In this chapter, a novel method to help power plant designers to determine the optimal battery energy storage capacity to integrate into any solar PV power plant is provided. The proposed algorithm minimizes the potential power curtailment and optimizes the utilization rate of the batteries storage system. The algorithm can be applied to any grid-connected solar PV power plant under delivery power restrictions, regardless of power capacity and location. The algorithm has been implemented to a simulated power plant with delivery limitations based on a real case, and results with the optimal battery capacity show that the system would be able to recover up to 83% of the curtailed energy and a yearly average capacity utilization of 56%. Moreover, the BESS operation has been validated with a scaled model run in Simulink and laboratory measurements, achieving 98% of curtailed energy recovery rate and a 57% of average capacity utilization.
Article
The lithium-ion battery energy storage systems (ESS) have fuelled a lot of research and development due to numerous important advancements in the integration and development over the last decade. The main purpose of the presented bibliometric analysis is to provide the current research trends and impacts along with the comprehensive review in the field of the grid-connected lithium-ion battery (LIB) ESS within the year 2010–2021. The research has been performed using refined keyword searches on grid-connected LIB ESS in the Scopus database and the data of the top 100 highly cited articles were extracted. The research trend has shown that the grid-connected LIB ESS literature has increased substantially between 2016 and 2021, compared to the period 2010–2015. The bibliometric analysis consists of detailed keyword co-occurrence network analysis, co-authorship map, distribution of articles over countries, journals, research types, and subject categories. The evaluation of highly cited articles identifies numerous aspects, including methodologies and systems, issues, and challenges, to determine existing constraints and research gaps. The process of deciding, developing, and evaluating the highly cited articles, is expected to contribute to a methodical foundation for potential progress of grid-connected LIB ESS, as well as identify emerging pathways for future researchers. This study may act as a guideline providing future directions towards improving energy efficiency, environmental sustainability, reliability, and flexibility of the LIB ESS integrated power system.
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Current models about the epidemiology, and pathophysiology, of individual affected with severe acute respiratory syndrome corona virus-2 (SARS2) infection presents a causative link between congenital heart disease, elevation in arterial blood pressure, airway obstruction, and pulmonary hypertension preconditions. The propensity to infection is influenced by particulate matter and poor air quality that is often exhibited in the processes of generating electrical power or operation of heavy industries (steel or cement manufacturing). This is in addition to the well-document rise of carbon dioxide, generation of acid rain, greenhouse gases, and changes in global weather patterns. The combined threat of global warming and the SARS2 epidemic has focused minds on the mitigation strategies by substituting fossil fuels with cleaner alternates or replacement. One path for the utilization of a cleaner energy production system is the conversion of coal to hydrogen production as the hydrogen-based economy is discussed. The challenges and likely implementation of hydrogen as an emerging energy resource during the transition from coal are described, taking into account the problems related to hydrogen production, distribution, storage, and use. The integration of renewable and nonrenewable hydrogen sources (electron, photon, pumped hydro, or carbon) is evaluated by taking into account their availability, levelized cost, and the efficiency to transform these resources into hydrogen.
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In this paper, CeVO4 nanostructures were produced with controlled hydrothermal method using hydrazine, cerium nitrate, and ammonium vanadate as reactants. Reaction control was performed utilizing hydrazine and ethylenediamine as new reactants. Other effective parameters such as solvent and surfactant were also carefully studied and optimized. The products were then identified through XRD, EDS, FTIR, FESEM, and BET analyses. FESEM results showed that by adjusting the concentration of ethylenediamine, hydrazine, and PVP surfactant, a rod-shaped morphology with suitable porosity could be created. Due to the high potential of CeVO4 in electrochemical processes, it was first employed for electrochemical storage of hydrogen. The amount of hydrogen storage in nanostructures produced with rod-shaped morphology was about 2575 mAh/g, which is very significant compared to products obtained with sodium hydroxide with spherical morphology.
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The present work addresses modelling, control, and simulation of a micro-grid integrated wind power system with Doubly Fed Induction Generator (DFIG) using a hybrid energy storage system. In order to improve the waveforms (voltages and currents) quality supplied to the grid, instead of a two level-inverter, the rotor of the DFIG is supplied using a three-level inverter. A new adaptive algorithm based on combined Direct Reactive Power Control (DRPC) and fuzzy logic controls techniques is applied to the proposed topology. In this work, two topologies are proposed. In the first one, the active power injected into the grid is smoothened by using an economical hybrid battery and super-capacitor energy storage system. However, in the second one, the wind excess energy is used to produce and store the hydrogen, and then a Solid Oxide Fuel Cell system (SOFC) is utilized to regenerate electricity by using the stored hydrogen when there is not enough wind energy. To avoid overcharging, deep discharging of batteries, to mitigate fluctuations due to wind speed variations and to fulfil the requirement of the load profile, a power management algorithm is implemented. This algorithm ensures smooth output power in the first topology and service continuity in the second. The modelling and simulation results are presented and analysed using Matlab/Simulink.
Article
The optimal algorithm of Energy Storage System (ESS) has gained remarkable attention in developing a microgrid (MG) system to reduce the intensity of carbon emission in the electricity sector and alleviate the environmental impact by 2050. This article provides a historical background and a comprehensive analysis of the optimal algorithm of ESS in MG applications. A brief search has been directed through the Scopus database with some predefined conditions on the last week of January 2021 over 11 years to select the top-cited articles. This bibliometric study is evaluated in this field over the last decades based on the year of publication, interrelation of co- occurrence keywords, articles type, country of origin, journal, and publisher that published the 120 top-cited articles. A sum of 4995 articles was revealed within the year 2010 to 2020 in the field of the optimal algorithm of ESS in MG applications, and the top-most 120 papers were received in total 23003 citations (mean-119.69; median-157.5). Articles having the highest citation revealed in 30 different journals, 27 different regions and 6 different publishers. This bibliometric approach of ESS in MG applications offers the trends of research, gaps of this field, and knowledge essential for further development and advancement in this area. It is predicted that extracting, evaluating, and investigating the top-most cited articles will support further research in the optimal algorithm of ESS in MG applications.
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Microgrids (MGs) have emerged as a viable solution for consumers consisting of Distributed Energy Resources (DERs) and local loads within a smaller zone that can operate either in an autonomous or grid tide mode. The DERs usually utilize Renewable Energy Resources (RERs), which have the advantages of meeting enhanced power demand, mitigating the pollutants of the environment, natural source of energy, needs minimal maintenance and cheap. Although MG integration provides several benefits, it faces many challenges and issues in its control and management, which can be effectively dealt with incorporating Energy Storage System (ESS) technologies into MGs. The addition of ESS to MGs has acquired increased attention as ESS can store energy during off-peak hours and deliver when required during peak hours. However, despite so many benefits, the ESS faces numerous issues in its integration, such as control, protection, state of charge (SoC), state of discharge (SoD), safety, life span, capacity, reliability and cost. So, to enhance the application of ESS in MG, the above issues need to be dealt with seriously. This research paper highlights the integration of ESS for MG application with a comprehensive review of issues, control methods, challenges, solutions, application, and overall management prospects. Further, the future trends and real time applications are also elucidated, which remarkably contributes to developing a cost effective and robust ESS architecture having a longer life span for renewable MGs application. Thus, an overview of this survey article's projected insights contributes to developing a techno-economic and effective integration of ESS with an extended life cycle for green MG employment.
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The paper presents a technical, economic and environmental analyses of a chamber furnace used to heat the charge before forging. The energy efficiency of the furnace before the modernization was 18%, after the modernization it was 31% (partial modernization due to large financial outlays). Other variants were also analysed: complete modernization, the variant of furnace modernization with 30% hydrogen content in the gas and the variant with 100% hydrogen as fuel. The analyses showed that with the current gas price (0.025 EUR/kWh) and the price of emission allowances (nearly 60 EUR/MgCO2) and 100 cycles/year, the difference in Net Present Value (NPV) before base variant and partial modernization is around 900,000 EUR and before base variant and full modernization is 1,200,000 EUR. The introduction of the gas and 30% of hydrogen co-combustion option versus the base scenario option for 150 cycles per year results in a NPV difference of at least 2 million EUR. The option of 100% hydrogen as a fuel is the most advantageous from the point of view of reducing CO2 emissions - it is largely influenced by the rising prices of CO2 emission allowances.
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The article aims to develop an optimisation model for power sector development and propose the desired direction of using energy storage technologies in the analysed period to distribution system operators (DSO) to develop renewable energy on a regional and local scale. The article presents the results of research on various types of energy storage technologies that can be used in the distribution system, such as a reservoir with EDLC (Electric Double-Layer Capacitors) supercapacitors, a reservoir with LIC (Lithium-Ion Capacitor) supercapacitors, a reservoir with LFP (Lithium Ferro) batteries. Phosphate LiFe PO4), a container with LTO (Lithium Titanate Oxide) batteries and a container with VRLA (Valve Regulated Lead Acid) batteries. It should be emphasised that due to the continuously more frequent problems with increased fluctuations in active power in distribution networks, the proposed model for optimising the use of electricity is an important approach to the rationalisation of actions and decisions made by distribution network operators (DSO). The research undertaken contributes to the development of knowledge concerning low carbon energy transition, as well as the energy storage subsystem.
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The ever‐growing demand in modern power systems calls for the innovation in electrochemical energy storage devices so as to achieve both supercapacitor‐like high power density and battery‐like high energy density. Rational design of the micro/nanostructures of energy storage materials offers a pathway to finely tailor their electrochemical properties thereby enabling significant improvements in device performances and enormous strategies have been developed for synthesizing hierarchically structured active materials. Among all strategies, the direct conversion of precursor templates into target micro/nanostructures through physical and/or chemical processes is facile, controllable, and scalable. Yet the mechanistic understanding of the self‐templating method is lacking and the synthetic versatility for constructing complex architectures is inadequately demonstrated. This review starts with the introduction of five main self‐templating synthetic mechanisms and the corresponding constructed hierarchical micro/nanostructures. Subsequently, the structural merits provided by the well‐defined architectures for energy storage are elaborately discussed. At last, a summary of current challenges and future development of the self‐templating method for synthesizing high‐performance electrode materials is also presented. The micro/nanostructure design via self‐templating method offers a viable way to significantly improve the electrochemical performances of functional materials. This review introduces five main self‐templating mechanisms and compares the merits of different micro/nanostructures for energy storage. Furthermore, a summary of current challenges and the prospect of self‐templating strategy for constructing high‐performance electrode materials are also presented.
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Environmental pollution and global warming have propelled the research activities toward the substitution of toxic materials with environmentally acceptable components in various spheres. Lithium‐ion battery (LIB) is exorbitantly used in different electronic devices in the present era and thus generates huge toxic electronic waste, which has become a global concern. Different approaches have been put forward to replace the commonly used materials for the fabrication of LIBs with processed biomass. This review discusses the significance and application of different biomass for fabricating electrodes and binders for LIBs. The electrochemical properties of the developed LIBs have also been discussed in detail. In addition, the required improvements have been put forth, so that biomass can be extensively used in future LIB to reduce the amount of generated toxic electronic wastes. Application of biowaste for the synthesis of Li‐ion battery. Morphology of the synthesized materials. Electrochemical properties of the synthesized materials. Efficiency of the natural products as components in Li‐ion batteries. The environmental safety of the materials as LIB components Conversion of different biowastes to materials in lithium‐ion batteries.
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Since they firstly appeared in 2014, paper-based microfluidic fuel cells (PMFC) have received great attention in the past few years, mainly being used for sensors, wearable devices, point-of-care testing and diagnostics. This fuel cell technology exploits the intrinsic characteristics of paper substrate and microfluidic flows of reactant streams eliminating the need for external pumps and conventional membranes. PMFCs operate in a co-laminar flow configuration, and the absence of convective mixing across the liquid–liquid interface of two streams forms a distinct diffusive mixing region, which acts as a pseudo–membrane. The hydrophilicity and porosity of paper substrate allows reactants to flow by capillarity with the assistance of an absorbent pad. Ions can be transported across the channel through the mixing region to reach the other side of the channel and complete ionic conduction. To date, several fuels have been utilised in PMFCs, such as formate, hydrogen, formic acid, hydrogen peroxide, hydrocarbons, borohydride, hydrazine, and biofuels, each of which has specific advantages and disadvantages. This review article summarises the growth of PMFC technology, from its invention in 2014 until the present, with emphasis on fundamentals, fabrication methods, unit cell performance with various fuels, performance achievements, design considerations, and scale-up options. The applications and main challenges associated with the current status of the technology are provided along with future perspectives. Investigations in recent years have shown that PMFCs developed with different fuels enhance power density from several µWcm⁻² to several mWcm⁻² and that stacking multiple individual cells increases the working voltage. Moreover, enzymatic and microbial PMFCs show great potential to be used as wearable devices, sensors and in lab-on-chip devices.
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With the intensification of energy shortages and environmental pollution, new energy sources represented by wind and solar energy have received global attention. Although the proposal of hydraulic wind turbines effectively solves the problems of traditional wind turbine transmission impact and complicated installation and maintenance, further exploration is needed on how to solve the randomness and intermittency of wind. The introduction of energy storage technology into wind power provides a way to solve this problem. This article mainly reviews the energy storage technology used in hydraulic wind power and summarizes the energy transmission and reuse principles of hydraulic accumulators, compressed air energy storage and flywheel energy storage technologies, combined with hydraulic wind turbines. It also discusses the functions of the energy storage system in terms of the stabilizing speed, optimal power tracking, power smoothing, and power system frequency modulation when generating power from hydraulic wind turbines. Finally, the development and potential application of energy storage technology in hydraulic wind turbines in the future are predicted.
Article
The power system faces significant issues as a result of large-scale deployment of variable renewable energy. Power operator have to instantaneously balance the fluctuating energy demand with the volatile energy generation. One technical option for balancing this energy demand supply is the use of energy storage system. Financial and economic assessment of innovative energy storage systems is important as these technologies are still in their early stages of development with various opportunities and uncertainties including technological and financial risks. This work models and assesses the financial performance of a novel energy storage system known as gravity energy storage. It also compares its performance with alternative energy storage systems used in large-scale application such as PHES, CAES, NAS, and Li-ion batteries. The results reveal that GES has resulted in good performance metrics including IRR and NPV of project and Equity, as well as ADSCR, and LLCR. In addition, for a 1 GW power capacity and 125 MWh energy capacity system, gravity energy storage has an attractive LCOS of 202 $/MWh. The LCOS comparison has shown that GES system is a cost-effective technology as compared to its counterparts. From a financial and an economic perspective, the studied energy storage systems are feasible technologies to store large scales energy capacities because they generate sufficient returns for project investors, have a high ability to service debt payments from cash flows, and, most importantly, achieves sufficient financial performance.
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Herein, a series of CoIIIcorroles with different meso-substituents were successfully functionalized on gold electrodes through self-assembled axial coordination with 4-(methylthio)pyridine (MTP) and 4-(4-methylthiobenzo)pyridine (MTPP). The surface modified gold electrode performed enhanced and tunable electrochemically catalyzed hydrogen evolution behaviors that demonstrates the tunable surface molecular engineering of CoIIIcorroles via self-assembled monolayer is an effective strategy for energy related small molecule activations. Additionally, the CoIIIcorrole with electron-withdrawing meso-substituents axially coordinated with expanded conjugation system, 4-(4-methylthiobenzo)pyridine (MTPP), has the best performance of electrochemically catalyzed hydrogen evolutions.
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This study evaluates the potential benefit of retrofitting existing conventional cascade hydropower stations (CCHSs) with reversible turbines so as to operate them as pumped hydro energy storage (PHES) systems. We examine the energy generation and storage problem for a CCHS with two connected reservoirs that can be transformed into a PHES system in a market setting where the electricity price can be negative. We formulate this problem as a stochastic dynamic program (SDP) under uncertainty in the streamflow rate and electricity price. We analytically derive an upper bound on the profit improvement that can be obtained from the PHES transformation. We conduct numerical experiments with data-calibrated time series models and observe that the PHES system provides a greater benefit under more limited streamflow conditions or more frequently observed negative prices.
Article
In this work, nitrogen-doped graphene foam was synthesized by using hydrothermal routes. In the first step, graphene was synthesized by utilizing a modified Hummer's method and nitrogen-doped graphene foam was then synthesized at 180 oC by using an ammonia and graphene solution for 12 hours. X-ray photon spectroscopy (XPS) was applied to determine the extent of doping by nitrogen on the graphene foam; three N-peaks were observed at 398.25, 399.69, and 401.46 eV, and XPS also showed that 6 at% of the synthesized graphene foam consisted of nitrogen atoms. The capability of this foam to absorb hydrogen was evaluated in a 6 M KOH solution through electrochemical impedance spectroscopy (EIS), galvanostatic charge/discharge, and cyclic voltammetry (CV) analysis. The hydrogen storage capacity of the achieved N-doped GF, showing the value of 1916.5 mAh.g⁻¹ significantly improved in comparison to that of pure graphene in previous work, due to the increasing electronegative sites at the surface of the graphene foam.
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Utilizing battery energy storage system is considered to be a reliable approach to improve the stability of modern power grid. By properly controlling the battery energy storage system, the redundant power can be absorbed and the lack of power can be supplemented. The control strategy of power conversion system directly affects the performance of battery energy storage system. Therefore, an improved active disturbance rejection control algorithm for power conversion system with LCL filter is presented in this paper. First of all, a pole placement strategy based on full state feedback is implemented in order to solve the resonance problem of LCL filter. Secondly, the total internal and external disturbances of power conversion system are compensated on basis of a linear extended state observer for purpose of improving the system robustness against inevitable interferences and parameter uncertainty. Furthermore, the stability of presented control strategy is analyzed and discussed in detail. Finally, the simulation and experimental results extracted based on a 2.6 kVA prototype are both provided, which can confirm the feasibility and correctness of the control strategy.
Chapter
The renewable resources are expanded to replace the power plants with high carbon intensity, such as coal plants. Gas-fired power plants are the main linkage between these two networks. Due to their characteristics, such as fast ramping rate, these plants complement the lack of renewables, and hence the intermittent nature of RES in the power system will be reflected in the gas network demand. As a solution, flexibility options, such as storage systems, bidirectional compressors, and power-to-gas (P2G) systems, are employed to cope with the imposed intermittency to the energy system. Taking into account the proposed issues, in this chapter, different types of flexibility options are firstly introduced, including their uses and mathematical models. After that, the contribution of these components in mitigating the intermittency and variability of RES is investigated based on previous projects and studies.
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Alkaline zinc-iron flow battery (AZIFB) is promising for stationary energy storage to achieve the extensive application of renewable energies due to its features of high safety, high power density and low cost. However, the major bottlenecks such as the occurrence of short circuit, water migration and low efficiency have limited its further applications, of which an ion-conducting membrane acts as a pivotal role in addressing these issues. The benchmark Nafion series membranes or anion-exchange membranes are confronted with their low ionic conductivity or poor stability in alkaline media. Therefore, a membrane is required to possess (1) excellent stability to avert the occurrence of short circuit resulted from the destruction of zinc dendrite and degradation of membrane caused by alkaline media, (2) low area resistance and high selectivity to achieve a high efficiency in time of the charge-discharge procedure of AZIFB. In this review, we will start from a brief introduction of AZIFB and cover the categories of membranes applied in AZIFB. And then the fundamental aspects of the membrane, including ion transport mechanism, fabrication & structure design and performance optimization will be highlighted. Finally, the challenges and prospects of the membranes for AZIFB applications will be briefly proposed and discussed.
Article
Background: A cost-effective solution for the design of distributed energy storage systems implies the development of battery performance models yielding a suitable representation of its dynamic behaviour under realistic operation conditions. Methods: In this work, a lithium-ion battery (LIB) is tested to be further modelled and integrated into an existing energy management control system. This specific LIB (5.0 kW /9.8 kWh) is integrated with a commercial inverter and solar photovoltaic (PV) system (3.3 kWp) as part of a microgrid that is also encompassing other storage technologies at the University of Évora, Pole of INIESC – National Research Infrastructure for Solar Energy Concentration. The battery and the inverter are fully characterized through the implementation of a testing protocol aiming at better describing the battery performance. Then, a battery model is built upon both the existent LIB description and experimental fitting regression, for real-time predictive optimization control development. Considering the pre-determined efficiency of the inverter, the model allows to obtain the voltage curve, the series resistance (i.e., to describe instantaneous voltage drop/rise and transients), and the state of charge (SOC) and/or energy capacity, based on the current input. The developed model is validated through the comparison with the experimental results. Results: In discharge state, the model approach presented a higher voltage RMSE (root mean square error) of 5.51 V and an MRE (maximum relative error) of 5.68 %. Regarding SOC the MRE obtained was approximately 6.82 %. In charge state, the highest RMSE voltage was 5.27 V, with an MRE of 6.74 %. Concerning SOC, the MRE obtained was approximately 6.53 %. Conclusions: The developed setup allowed us to perform the necessary characterization tests under real operating conditions. Based on computational effort, simplicity of use, and the associated model error compared with the experimental data, generally, the model describes the battery behaviour.
Chapter
Rare-earth tungstates are negatively charged oxytungstate ions widely investigated in luminescence and catalysis fields. In addition, tungstate ions can easily polymerize to form polytungstates. However, only few materials containing essential tungstates are reported; therefore, the wide range applications of tungstate-based materials in modern industries are limited. In this chapter, primarily, the controlled synthesis and properties of tungstate-based materials are discussed. Furthermore, the various tungstate-based materials are explained/categorized by collecting the novel materials in this field such as rare-earth oxides, oxysalts, etc. Finally, this chapter presents the application of tungstate-based materials in modern technologies such as energy conversion and storage. With the newly developed technologies, it is critical to develop more rare-earth tungstate- based materials particularly in nanostructures as well as their advanced applications in the future, since these are often vague and long-winded.
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Energy systems are progressive and revolutionary for their alternative resources, technical developments, demands, effectiveness and environmental effects. The recently published research's goal is to assess and evaluate the systems that are already in operation and those that will be in the future. Energy can be stored as electrical energy such as supercapacitors (SCs) and superconducting magnetic energy storage (SMES) etc., mechanical energy such as pumped hydro energy storage (PHES), compressed air energy storage (CAES) and flywheel energy storage (FES) etc., chemical energy, electrochemical energy such as batteries and fuel cells etc., and thermal energy. Performance of these energy storage systems (ESSs) have been evaluated in terms of energy density, power density, power ratings, capacitance, discharge-time, energy-efficiency, life-time and cycling-times, and costs. Supercapacitors provide highest power density (>10,0000 W/l), while hydrogen fuel cells provide highest energy density (500-3000Wh/l) among other EESs. Batteries also provide high energy density(200-500Wh/l). The energy efficiency is found highest in SMES system (95-98%), and lowest in TES system (30-50%). Moreover, batteries and supercapacitors have the cycle efficiency above 90%. PHES and CAES seem to be the most cost-effective energy storage systems reviewed in this analysis in terms of $/kWh. In addition, power-based capital cost of supercapacitors is lower (100-300$/kW) compared to energy-based capital cost of supercapacitors (300-2000$/kWh). In comparison with power-based capital costs, the energy-based capital cost of batteries is lower, which is 150-400$/kWh for Lead-acid battery, and <300$/kWh for Li-ion battery. This essay may help researchers in choosing the advanced energy storage technologies for relevant purposes.
Article
Background: A cost-effective solution for the design of distributed energy storage systems implies the development of battery performance models yielding a suitable representation of its dynamic behaviour under realistic operation conditions. Methods: In this work, a lithium-ion battery (LIB) is tested to be further modelled and integrated into an existing energy management control system. This specific LIB (5.0 kW /9.8 kWh) is integrated with a commercial inverter and solar photovoltaic (PV) system (3.3 kWp) as part of a microgrid that is also encompassing other energy storage technologies at the University of Évora, Pole of INIESC – National Research Infrastructure for Solar Energy Concentration. A testing protocol fully characterizes the battery and the inverter efficiency to describe their performance better. Then, a battery model is built upon both the existent LIB description and experimental fitting regression. The model allows obtaining the voltage curve, the internal resistance (i.e., to describe instantaneous voltage drop/rise and transients), and the state of charge (SOC) and/or energy capacity based on the current input. The developed model is validated through the comparison with the experimental results. Results: The model approach presented a higher voltage RMSE (root mean square error) of 5.51 V and an MRE (maximum relative error) of 5.68 % in the discharge state. Regarding SOC, the MRE obtained was approximately 6.82 %. In the charge state, the highest RMSE voltage was 5.27 V, with an MRE of 6.74 %. Concerning SOC, the MRE obtained was approximately 6.53 %. Conclusions: The developed model is validated through the comparison with experimental results. Based on computational effort, simplicity of use and the associated model error, the approach is validated to the regular conditions of the commercial battery pack to be incorporated in the next research step, following a bottom-up modelling approach for an increasingly more complex smart grid.
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Since the early beginnings of the electricity system, storage has been of high relevance for balancing supply and demand. Through expanded electricity production by variable renewable technologies such as wind and photovoltaics, the discussion about new options for storage technologies is emerging. In addition, the electricity markets were subject to remarkable alterations. Some developments which describe these changes are increasing electricity generation from variable renewables and the continuing decentralization. These developments have led, among other required transformations, to demands for additional capacities of storage technologies. However, their economics will play a crucial role in their effective market penetration in the following years. The core objective of this work is to conduct a review on the relevance of storage options for electricity and its costs, economics, welfare effects, and on issues of electricity market design. In addition, based on expected Technological Learning prospects for future economics are derived. The major result is that the perspectives of electricity storage systems from an economic viewpoint are highly dependent on the storage's operation time, the nature of the overall system, availability of other flexibility options, and sector coupling. All market‐based storage technologies have to prove their performance in the large electricity markets or if applied decentralized, the (battery) systems compete with the electricity prices at the final customers level when the battery costs are also taken into consideration. Yet, new storage capacities should only be added when it is clear that electricity generation from variable renewables will also be expanded in a way that excess generation is expected. This article is categorized under: Policy and Economics > Green Economics and Financing Energy and Power Systems > Energy Infrastructure Emerging Technologies > Energy Storage Through expanded electricity production from variable renewable technologies such as wind and photovoltaics, the discussion about new options for storage technologies is emerging. The core objective of this work is to conduct a review on the relevance of storage options for electricity and its costs, economics, welfare effects and on issues of electricity market design. The major result is that the economics of electricity storage are highly dependent on storage operation time, availability of other flexibility options and sector coupling options.
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Today, barium titanate nanowires as a piezoelectric material can transmit more energy and generate energy during energy harvesting. The silicon substrate is of great importance in some respects, especially the issue of integration and a hybrid nanogenerator based on BaTiO3 NRs / PDMS composite film on silicon substrate is introduced. Here, FTO layer is used both as seed layer for the TiO2 NRs and as bottom electrode by pyrolysis spray method. The growth of BaTiO3 NRs consists of two hydrothermal stages: the first is growing the TiO2 nanorods and the second is the conversion of TiO2 to BaTiO3 (BTO). To increase the output voltage of the nanogenerator (NG), the surface roughness of silicon substrate is investigated. The results show that the peak-to-peak voltage of the NG output, which is made on a micro-machined substrate with the pattern of micro-digits at a height of 20 μm, compared to the smooth substrate is 1.92 to 1.48 V in frequency of 20 Hz. which is a 30% increase and the piezoelectric coefficient of the grown BTO is around 200 pC/N.
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Lamina and laminate mechanical properties of materials suitable for flywheel high-speed energy storage were investigated. Low density, low modulus and high strength composite material properties were implemented for the constant stress portion of the flywheel while higher density, higher modulus and strength were implemented for the constant thickness portion of the flywheel. Design and stress analysis were used to determine the maximum energy densities and shape factors for the flywheel. Analytical studies along with the use of the CADEC-online software were used to evaluate the lamina and laminate properties. This study found that a hybrid composite of M46J/epoxy–T1000G/epoxy for the flywheel exhibits a higher energy density when compared to known existing flywheel hybrid composite materials such as boron/epoxy–graphite/epoxy. Results from this study will contribute to further development of the flywheel that has recently re-emerged as a promising application for energy storage due to significant improvements in composite materials and technology.
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Due to the new challenge of meeting number-based regulations for particulate matter (PM), a numerical and experimental study has been conducted to better understand particulate formation in engines fuelled with compressed natural gas. The study has been conducted on a Heavy-Duty, Euro VI, 4-cylinder, spark ignited engine, with multipoint sequential phased injection and stoichiometric combustion. For the experimental measurements two different instruments were used: a condensation particle counter (CPC) and a fast-response particle size spectrometer (DMS) the latter able also to provide a particle size distribution of the measured particles in the range from 5 to 1000 nm. Experimental measurements in both stationary and transient conditions were carried out. The data using the World Harmonized Transient Cycle (WHTC) were useful to detect which operating conditions lead to high numbers of particles. Then a further transient test was used for a more detailed and deeper analysis. Finally 3-D Computational Fluid Dynamics (CFD) simulations were performed and the numerical results obtained were compared to particle size distributions (PSDs) derived from the experimental measurements carried out in stationary conditions. In this way the influences of engine load and regime on particle size distribution (PSD) were determined. A semi-detailed soot model and a chemical kinetic model, including poly-aromatic hydrocarbon (PAH) formation, were coupled with a spark ignition model and the G equation flame propagation model for the SI engine simulations and for predictions of soot mass and particulate number density. Qualitative agreements of in-cylinder particle distributions were obtained and results are helpful to understand particulate formation processes.
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