Smart Grid Energy Storage Research Articles

Fabrication of cathode composite Co3O4/CC and study on electrochemical properties of zinc cobalt battery

Purpose Aqueous zinc-ion battery has broad application prospects in smart grid energy storage, power tools and other fields. Co3O4 is one of the ideal cathode materials for water zinc-ion batteries due to their high theoretical capacity, simple synthesis, low cost and environmental friendliness. Many studies were concentrated on the synthesis, design and doping of cathodes, but the effect of process parameters on morphology and performance was rarely reported. Design/methodology/approach Herein, Co3O4 cathode material based on carbon cloth (Co3O4/CC) was prepared by different temperatures hydrothermal synthesis method. The temperatures of hydrothermal reaction are 100°C, 120°C, 130°C and 140°C, respectively. The influence of temperatures on the microstructures of the cathodes and electrochemical performance of zinc ion batteries were investigated by X-ray diffraction analysis, scanning electron microscopy, cyclic voltammetry curve, electrochemical charging and discharging behavior and electrochemical impedance spectroscopy test. Findings The results show that the Co3O4/CC material synthesized at 120°C has good performance. Co3O4/CC nanowire has a uniform distribution, regular surface and small size on carbon cloth. The zinc-ion battery has excellent rate performance and low reaction resistance. In the voltage range of 0.01–2.2 V, when the current density is 1 A/g, the specific capacity of the battery is 108.2 mAh/g for the first discharge and the specific capacity of the battery is 142.6 mAh/g after 60 charge and discharge cycles. Originality/value The study aims to investigate the effect of process parameters on the performance of zinc-ion batteries systematically and optimized applicable reaction temperature.

Evaluation and economic analysis of battery energy storage in smart grids with wind–photovoltaic

Abstract The large number of renewable energy sources, such as wind and photovoltaic (PV) access, poses a significant challenge to the operation of the grid. The grid must continually adjust its output to maintain the grid power balance, and replacing the grid power output by adding a battery energy storage system (BESS) is a perfect solution. Based on this, this paper first analyzes the cost components and benefits of adding BESS to the smart grid and then focuses on the cost pressures of BESS; it compares the characteristics of four standard energy storage technologies and analyzes their costs in detail. It is challenging to gain benefits from BESS consisting of lead–acid batteries or vanadium redox flow batteries, while BESS consisting of lithium-ion batteries can gain a meager number of benefits. The best-performing one is BESS, consisting of sodium-ion batteries, which can bring considerable benefits to the system and can finally analyze the feasibility of sodium-ion batteries applied to wind–PV-containing power grids. Lithium-ion batteries are widely used because of their excellent performance, and sodium-ion batteries have a similar version to lithium-ion batteries and are more suitable for grid energy storage due to their lower price and more abundant raw materials.

Reinforcement learning-based energy storage management in smart grids

This study investigates the use of reinforcement learning (RL) techniques as a dynamic control mechanism to enhance the management of energy storage in smart grid systems. The research aims to optimize the efficiency of energy storage operations by analyzing collected data from different time intervals in a simulated smart grid scenario. An evaluation of the energy storage status reveals a consistent upward trend in the quantity of stored energy, with a 30% cumulative growth across time intervals. An examination of the demand and supply of the grid indicates a persistent insufficiency of energy, with an average shortfall of 15% in meeting the requirements of the system. Through the use of reinforcement learning (RL) methodologies, the system exhibits a remarkable 450% improvement in cumulative rewards, providing substantiation of its capacity to acquire knowledge and adjust its behavior over time. The system's actions indicate a purposeful shift in strategy, with 75% of instances involving charging procedures, emphasizing a commitment to energy preservation and the buildup of stored energy. Despite a shift in approach, persistent disparities between grid demand and supply need the implementation of more accurate technologies for effective energy management. The findings highlight the effectiveness of using reinforcement learning (RL) for managing energy storage in smart grids. This approach improves energy reserves and optimizes energy storage by altering actions accordingly. These insights contribute to the advancement of adaptive energy management strategies, resulting in the development of sustainable and resilient smart grid infrastructures.

Facile preparation of urchin-like morphology V2O3-VN nano-heterojunction cathodes for high-performance Aqueous zinc ion battery

Rechargeable aqueous zinc ion batteries (RAZIBs) are of interest for energy storage in smart grids. However, slow Zn2+ diffusion kinetics, insufficient active sites, and poor intrinsic conductivity are always challenging to exploit the huge potential of the batteries. Here, we prepare V2O3-VN nano-heterojunction composites with sea urchin-like morphology as the cathode for AZIBs. The electrode achieves high capacities (e.g., 0.1 A g−1, 532.6 mAh g−1), good rate and cycle performance (263.4 mAh g−1 at 5 A g−1 current density with 90.8% capacity retention). Detailed structural analyses suggest that the V2O3-VN composite is composed of different crystal planes of V2O3 and VN, which form an efficient heterogeneous interfacial network in the bulk electrode, accounting for its good electrochemical properties. Theoretical calculations reveal that compared with V2O3, VN and physically mixed V2O3/VN, the V2O3-VN heterostructure exhibits good cation adsorption and electrode conductivity, thereby accelerating the charge carrier mobility and electrochemical activity of the electrode. Moreover, ex-situ characterization techniques are utilized to investigate the zinc storage mechanism in detail, providing new ideas for the development of AZIBs cathode materials through the construction of heterojunction structures.

Smart grid energy storage capacity planning and scheduling optimization through PSO-GRU and multihead-attention

The energy problem in today’s society is becoming increasingly prominent, and the smart grid has become one of the important ways to solve the energy problem. Smart grid energy storage capacity planning and scheduling optimization is an important issue in the smart grid, which can make the grid more efficient, reliable, and sustainable to meet energy demand better and protect the environment. The core of smart grid energy storage capacity planning and scheduling optimization is maximizing the use of energy storage devices to balance the difference between power supply and demand to ensure the grid operation’s stability. Traditional planning methods are usually based on experience and rules, have low precision, and cannot adapt to the dynamic changes in the long-term development of the power grid. Therefore, this paper proposes a method that combines PSO-GRU (particle swarm Optimization (PSO)-gated recurrent unit (GRU)) and Multihead-Attention to realize smart grid energy storage capacity planning. And scheduling optimization. First, PSO-GRU models and predicts power grid data by searching for the optimal GRU model parameters; second, Multihead-Attention improves the model’s performance through the self-attention mechanism. Finally, we use the method to determine the optimal energy storage capacity and dispatching scheme for the efficient operation of smart grids. Our experiments use real power grid datasets and compare them with other common methods. Experimental results show that our proposed method has higher accuracy and stability than other methods and can better adapt to the dynamic changes of the power grid. This indicates that our method has good feasibility and applicability in practical applications and is significant for realizing the efficient operation of smart grids and energy saving and emission reduction.

A Comprehensive Review on Energy Storage System Optimal Planning and Benefit Evaluation Methods in Smart Grids

Smart grids are the ultimate goal of power system development. With access to a high proportion of renewable energy, energy storage systems, with their energy transfer capacity, have become a key part of the smart grid construction process. This paper first summarizes the challenges brought by the high proportion of new energy generation to smart grids and reviews the classification of existing energy storage technologies in the smart grid environment and the practical application functions of energy storage in smart grids. Secondly, optimization planning and the benefit evaluation methods of energy storage technologies in the three different main application scenarios, including the grid side, user side, and new energy side, are analyzed. The advantages and shortcomings of the current research are also pointed out. Furthermore, the paper sheds light on the pressing issues that demand further consideration in energy storage planning. Finally, the aspects that warrant attention in the future application and promotion processes are elucidated in detail, culminating in a comprehensive understanding of the energy storage technologies in smart grids.

Differentiated Configuration Options for Centralized and Distributed Energy Storage

With the rapid development of new energy power generation technology and the promotion and application of energy storage in smart grids, energy storage is more and more favored by people. Firstly, the energy storage technology is classified, and its role in the power grid is analyzed. Then, the economy of centralized and distributed energy storage is analyzed. Further, according to the technical and economic characteristics of centralized energy storage and distributed energy storage, the applications of these two types of energy storage are introduced. Finally, based on the characteristics of renewable energy in Jilin Province, recommendations are made for the placement of energy storage in Jilin Province in the context of “carbon neutrality and carbon peaking.”

Textured Na2V6O16·3H2O Cathode Tuned via Crystal Engineering Endows Aqueous Zn-Ion Batteries with High Rate Capability and Adequate Lifespan

Aqueous zinc-ion batteries (ZIBs) play a vital role in large-scale energy storage for smart grids due to their environmental friendliness, safety, and low cost. Unfortunately, the application of ZIBs has been challenged by the relatively low capacity of cathode materials, especially at higher rates, which originates from the sluggish diffusion of Zn ions. Herein, a crystal engineering strategy is explored for using bernesite, Na2V6O16·3H2O (NVO), for regulating the diffusion-preferable texture, which was beneficial for fostering Zn ions’ diffusion and thus guaranteeing a uniform concentration inside the cathode. An enlarged capacity at a higher rate was obtained, delivering a capacity of 156.9 mAh g–1 at the ultra-high current density of 20 A g–1, of which 140.6 mAh g–1 remained after 5000 cycles. The use of crystal engineering to regulate the texture of cathode materials paves the way to boost the application of NVO in aqueous ZIBs, which could be translated to design state-of-the-art cathodes for other battery systems.

(Digital Presentation) Understanding the Influence of Fe Doping Level on Na-Ion Diffusivity for P2-Na2/3Mn1-XFexO2 (x= 0, 1/3, 1/2) sodium-Ion Battery Cathode Material Using Molecular Dynamics Simulation

Global progression towards e-mobility to reduce the carbon footprint has led to the demand for smart grid energy storage systems. Amongst the available electrical energy storage technologies, rechargeable batteries serve as a pragmatic option to cater to the intermittent character of renewable energy supplies owing to their high energy efficiency and flexible power characteristics. In contrast to the existing lithium-ion batteries (LIBs), Na-ion batteries appear as a sustainable substitute due to their dependence on widely distributed, and abundant sodium reserves. However, the commercialization of Na-ion batteries has been hampered primarily by the inefficient performance of electrode materials particularly cathode. Among the prevailing cathode materials, the class of layered transition metal oxide with O3 and P2 structural configuration imparts decent specific capacity and has been studied extensively over the past few years. Though the presence of comparatively larger Na ions induces better initial capacity but suffer the drawback of undergoing complex phase transformation during charge-discharge cycling. Moreover, P2-phase exhibits lower diffusion energy barrier due to the direct passage of sodium ions from one prismatic site to another. Therefore, materials with the aforementioned P2 orientation have been synthesized deploying earth-abundant elements like Mn, and Fe for sodium-ion battery applications. To comprehend the diffusional behavior of Na-ions, we have carried out molecular dynamics simulation of P2-Na2/3Mn1-xFexO2 (x=0, 1/3, 1/2) material. The preliminary computational calculations reveal enhanced Na-ion self-diffusivity with increased Fe dopant onto P2-Na2/3MnO2 material, while the diffusivity showcased a decreasing trend with further increase in Fe substitution that might be ascribed to the phase stabilization aspect of Mn element and charge compensation attribute of Fe3+/Fe4+ and Mn3+/Mn4+ redox couples.

Guest editorial: Energy storage in smart grids

Guest editorial: Energy storage in smart grids

Review of Peak Shaving Features of the Power Box

In this review article, a considerable discussion and details on peak shaving strategies involving incorporation of the electric vehicles to the grid, integration of energy storage system, demand‐side management, and renewable energy sources have been presented. Three types of peak shaving using energy storage systems, such as the battery energy storage system, supercapacitor energy storage system, and flywheel energy storage system, have been explained with the advantages and disadvantages of the different approaches. In one of these studies, the integration of a renewable photovoltaic source with battery energy storage in peak shaving has successfully produced an annual savings of $155 675.00. The introduction to the cost–benefit and sustainable second‐life batteries energy storage and their relationship with electric vehicles is also described. Another study involving electric vehicles BYD e6, which have the cheapest energy storage cost of 0.1208 $ kWh−1 and participated the most in peak shaving, obtains the most significant individual net income compared to other vehicles. Different demand‐side management practices and their advantages are thoroughly discussed. Finally, this article also includes the challenges, importance, perspectives, future work suggestions, and improvements on peak shaving performance, such as implying the smart grid energy storage technology to achieve the Sustainable Development Goal 7.

Design and Implement of Staggered Parallel Lithium Battery Equalization Converter With Jumper Switches

To mitigate the pressure on energy storage and enhance the flexibility of the power system, lithium-ion batteries are widely utilized in large-scale energy storage in smart grids due to their superior charging and discharging performance and energy storage characteristics. Whereas the inconsistency of lithium battery cells has become a key issue that limits the overall performance of the battery pack. A novel flexible equalization converter is proposed to handle this issue. This converter is combined with a staggered parallel topology and jumper switched, which enables an energy transfer path to exist between any cell to the rest pack and any substring to the rest substring. The electromagnetic transient model and its small-signal model of the proposed converter have been developed in MATLAB to prove its effectiveness. Finally, the conclusion could be arrived at that the proposed topology shows a better performance compared to the traditional method.

Mechanisms of Degradation of the Air Cathode in an Alkaline Fuel Cell

Rechargeable zinc-air redox flow batteries have been reported as an energy storage technology that has high energy density, uses abundant low-cost raw materials, and has low environmental impact [1, 2]. Due to these characteristics, zinc-air batteries are attractive for both portable and smart-grid energy storage applications [1, 2]. However, the limited cycle life has been identified as a major problem for commercialization of zinc-air batteries [2].Flooding of the electrolyte within alkaline electrode pores is reported as one of the major causes of degradation and performance loss of the air cathode in these devices [1, 3]. To prevent the ingress of electrolyte in the zinc-air cathode, modifying the hydrophobicity and conductivity of the catalyst layer has been reported [4]. The ratio of carbon/binder has impact on ionic conductivity and gas transport in the electrode. In addition, it is observed that degradation of performance of the electrode without binder is faster than that with binder [4].In this study, degradation of the air cathode in the zinc air flow battery was investigated by measuring the variation in the cell voltage at a constant current density. The air cathode consisted of a sintered active layer (AL) composed of platinum nanoparticles supported on carbon (Pt/C), a carbon / PTFE backing layer (BL), and a nickel mesh current feeder. The experimental setup used a 6 M KOH electrolyte, with a zinc wire reference and nickel counter electrode. A control system for real time control of the operating temperature, pressure, and inlet air humidity was implemented to maintain stable operating conditions and record the data. Post-mortem (PM) analysis was conducted on the tested samples. The sample preparation method was carefully evaluated for the PM study to make sure that the KOH present in the pores is preserved during imaging.No significant degradation in the performance of the air cathode was observed after 148 hours at baseline operating conditions (current density of 200 mA cm-2 and 21% oxygen). In order to enable rapid evaluation of electrode durability, conditions for accelerated degradation of the air cathode were investigated. Under conditions of low oxygen stoichiometry (achieved by 50% drop in oxygen stoichiometry) and high current density (400 mA cm-2), the rate of degradation was accelerated and the lifetime of the air cathode was less than 24 hours. The lifetime of the air cathode was estimated based on significant increase in the potential loss ca. 0.3 V, while performing oxygen reduction from an air feed at baseline operating conditions. Polarization studies were performed on the air cathode after a significant performance loss during the accelerated degradation experiments. The results indicate that the air cathode degradation accelerated under conditions of oxygen mass transfer limitation. The increased potential loss is likely due to flooding of electrolyte inside the pores of the active layer of the electrode, which increases the mass transfer resistance for oxygen transport [5, 6].For evaluation of the impact of binder loading on air cathode degradation, three different loadings of polytetrafluoroethylene (PTFE) in the catalyst layer were used, and the performance and durability were compared. The morphology and microstructure of active and backing layers of the used air cathode was investigated by scanning electron microscopy (SEM). Cross sectional SEM images were carried out for PM analysis to investigate the penetration depth of KOH inside the active and backing layers after a significant potential loss was observed. Surface analysis of the active and backing layers were also conducted using Raman spectroscopy.

A Secure Lightweight Hardware-Assisted Charging Coordination Authentication Framework for Trusted Smart Grid Energy Storage Units

A Secure Lightweight Hardware-Assisted Charging Coordination Authentication Framework for Trusted Smart Grid Energy Storage Units

Integration of Low Melting Temperature Electrolyte in Thermal Batteries

Thermal batteries usually operate at temperatures higher than 400 °C. This high operating temperature requires a complex thermal and mechanical design of the battery components and hermetically sealed casing. Reduced operating temperature thermal cells can benefit from the majority of intrinsic characterizations of thermal batteries such as safety, robustness, and infinite shelf life while mitigating the challenges related to the high operating temperature batteries such as exotic thermal insulation materials, complicated internal pyrotechnic heat source, and heavy packaging. To integrate the thermal batteries into a wider range of applications such as bore-hole probes, smart grid energy storage, and geothermal energy applications, operating temperatures of these batteries should be reduced.The most common design for thermal batteries is pellet stacks. The pellet pressing fabrication method inherently causes issues due to the fragility of the pellets, making handling and assembly of the cells arduous. Additionally, due to the liquid nature of molten salt electrolyte used in these batteries, a structure to immobilize the electrolyte layer during the operation of the battery is required. The role of the immobilizing component is also to prevent short circuiting while the battery is affected by severe physical shock or vibration. The most commonly used binder material in today’s thermal batteries is magnesium oxide (MgO). Extensive investigations were conducted on the properties and the electrochemical effect of using MgO as the binding material, besides, its fabrication process is well optimized. However, using MgO is not without its drawbacks. To prevent short-circuiting during the cell operation especially in the presence of an external shock to the system, approximately 30 vol.% of the separator layer should be dedicated to MgO, resulting in lower than desired energy density. Ceramic felts showed promising results in recent studies. High level of porosity (e.g. 96% bulk porosity), outstanding stability at elevated temperatures, and mechanical stiffness could be the key to make batteries that can operate for a longer time.Our research group has previously developed a novel eutectic electrolyte mixture using potassium bifluoride and different lithium salts such as lithium fluoride as the low melting point electrolytes. In this research, initially, the integration of this electrolyte mixture in a thermal cell was tested. Consequently, aluminum oxide (Al2O3) and yttria-stabilized zirconia (YSZ) ceramic felts were loaded with the low melting electrolyte as an alternative to the current pellet-based separator layer. Finally, (i) the assembly of the cell, (ii) the thermal analysis of the components by differential scan calorimetry (DSC) method, (iii) the new electrolyte/ceramic-felt combination’s loading level, wetting properties, infiltration, and leakage, and (iv) electrochemical behavior of the new thermal battery such as discharge capability and energy density were investigated.

An Optimal Active Power Scheduling Strategy with Renewable Energy Based on Distributed Consensus Algorithms

Aiming at the influence of the uncertainty of renewable energy generation on the power distribution of smart grid, a distributed optimal scheduling strategy for smart grid energy storage units based on consensus algorithm was proposed. This method does not rely on the central controller, but through the local communication between the energy storage units, according to their own information and acquired neighbor information to adjust the deviation between the actual and planed power in real time. In addition, in order to verify that the algorithm can optimize the network loss, MATPOWER is used to calculate the network loss before and after optimization. The system simulation results show that the proposed distributed scheduling strategy can ensure that all storage units converge to the same optimal value, and make the power grid run more economically.

High-efficiency Bidirectional Buck–Boost Converter for Residential Energy Storage System

This paper proposes a bidirectional dc–dc converter for residential micro-grid applications. The proposed converter can operate over an input voltage range that overlaps the output voltage range. This converter uses two snubber capacitors to reduce the switch turn-off losses, a dc-blocking capacitor to reduce the input/output filter size, and a 1:1 transformer to reduce core loss. The windings of the transformer are connected in parallel and in reverse-coupled configuration to suppress magnetic flux swing in the core. Zero-voltage turn-on of the switch is achieved by operating the converter in discontinuous conduction mode. The experimental converter was designed to operate at a switching frequency of 40–210 kHz, an input voltage of 48 V, an output voltage of 36–60 V, and an output power of 50–500 W. The power conversion efficiency for boost conversion to 60 V was ≥98.3% in the entire power range. The efficiency for buck conversion to 36 V was ≥98.4% in the entire power range. The output voltage ripple at full load was <3.59 Vp.p for boost conversion (60 V) and 1.35 Vp.p for buck conversion (36 V) with the reduced input/output filter. The experimental results indicate that the proposed converter is well-suited to smart-grid energy storage systems that require high efficiency, small size, and overlapping input and output voltage ranges.

Fog-Computing-Based Energy Storage in Smart Grid: A Cut-Off Priority Queuing Model for Plug-In Electrified Vehicle Charging

Electric vehicles (EVs) are likely to become very popular within the next few years. With possibly millions of such vehicles operating across the smart cities, smart grid energy providers can be directly impacted by the charging of EV batteries. In order to reduce this impact and optimize energy saving, in this article, we propose a coordinated model for scheduling the plug-in of EVs for charging and discharging energy. The model is based on a new decentralized Fog architecture for smart grid in order to reduce the completion and communication delay of EV energy demand scheduling. To enhance the scheduling of EV demands and predict the future energy flows, we propose a plug-in system of EVs based on calendar planning. We develop a mathematical formalism based on Markov chains using a multipriority queuing theory with cut-off discipline in order to reduce the waiting time to plug-in. We implement three planning algorithms in order to assign priority levels and then optimize the plug-in time into each EV public supply station. To the best of our knowledge, this is the first article that proposes a model that tries to save energy by planning the plug-in of EVs using a cut-off priority queuing model and a decentralized Fog architecture. We evaluate the performances of our solution via extensive simulations using a realistic energy loads from the city of Toronto, and we compare it with other recent works.

CNT-Decorated Na4Mn2Co(PO4)2P2O7 Microspheres as a Novel High-Voltage Cathode Material for Sodium-Ion Batteries.

The Mn-based mixed polyanion is expected to be a promising cathode material for sodium-ion batteries applied to large-scale smart grid energy storage systems due to its stable three-dimensional crystal structure, low cost, and high energy density. Herein, a novel carbon nanotube (CNT)-modified mixed-polyanion material (Na4Mn2Co(PO4)2P2O7) with a high voltage of 3.86 V is synthesized by a facile spray-drying method. The well-designed Na4Mn2Co(PO4)2P2O7/C-CNTs microsphere has excellent electronic and ionic conductivity by virtue of the carbon nanotube conductive skeleton. The as-prepared Na4Mn2Co(PO4)2P2O7/C-CNTs composite exhibits a reversible initial discharge capacity of 96.1 mA h g-1 and an energy density of 371 Wh kg-1 at 0.1 C. Furthermore, Na4Mn2Co(PO4)2P2O7/C-CNTs and hard carbon are assembled into a full battery, which delivers an initial discharge capacity of 88.8 mA h g-1, a working voltage of 3.85 V, and a promising energy density of 249.9 Wh kg-1 at 0.1 C. Therefore, the outstanding performance makes the Na4Mn2Co(PO4)2P2O7/C-CNTs material a potential candidate for large-scale applications of sodium-ion batteries.

Vehicle‐for‐grid (VfG): a mobile energy storage in smart grid

Vehicle-for-grid (VfG) is introduced as a mobile energy storage system (ESS) in this study and its applications are investigated. Herein, VfG is referred to a specific electric vehicle merely utilised by the system operator to provide vehicle-to-grid (V2G) and grid-to-vehicle (G2V) services. The advantages of VfGs over the ESSs and plug-in electric vehicles (PEVs) include mobility of the VfGs across the distribution system and their complete availability for the system operator, respectively. In this study, VfGs are utilised by the distribution company (DISCO) to minimise the daily operation cost of the distribution system by providing the V2G and G2V services in optimal buses of the feeders. In addition, VfGs are applied by the generation company (GENCO) to minimise the daily operation cost of the generation system by providing the V2G and G2V services at optimal time periods. It is demonstrated that optimal application of VfGs has a considerable potential for cost reduction for both DISCO and GENCO. In fact, the DISCO and GENCO are benefitted because of the minimisation of feeders’ power loss and deferring the expensive generation units, respectively. Additionally, it is proven that cooperation of GENCO and DISCOs in utilisation of the VfGs has more benefit for them.