Development Of Energy Storage Systems Research Articles

High performance NiCoSe2@NiFe-MOF@AC Nanocomposite electrode for energy storage and precise detection of mono-sodium glutamate

Hybrid supercapacitors, a fascinating appliances that combines the best of both batteries and supercapacitors, showcase remarkable improvements in power and energy densities. Here, a two-step technique was used to synthesis NiCoSe2@NiFe-MOF. In first step NiCoS was synthesis using electrodeposition approach and in second step the NiCoSe2@NiFe-MOF was synthesis using vacuum-assisted filtering. The specific capacitance of the NiCoSe2@NiFe-MOF composite used as the supercapacitor electrode in a three-electrode system was (2882.5 F g−1) and specific capacity is 1729.8 C g−1, much greater than that of the NiCoSe2 electrode material which was 967.4 C g−1 at current density of 1.5 Ag−1, In addition, a hybrid supercapacitor device (NiCoSe2@NiFe-MOF//AC) has been developed and successfully demonstrates a specific capacity of 205.45 C g−1 at 0.5 A g−1. The energy density is measured in units of WhKg−1 with a numeric values of 78.3, while at 2.9 KWKg−1 the power density is recorded. This device has been tested for up to five thousands cycles of discharging (87.8%) and charging (94.2%), achieving an impressive capacity retention rate of 96.8%.Additionally, an amperometric immunosensor was fabricated by employing the NiCoSe2@NiFe-MOF nanocomposite to detect Mono-Sodium Glutamate (MSG). A constant linear association was observed between the concentration of MSG and the variation in current, encompassing the entire detection range of 0.05–200 μM. The findings of our study offer an exciting starting point for the development of energy storage systems with greater capacity.

Microporous tungsten oxide spheres coupled with Ti3C2Txnanosheets for high-volumetric capacitance supercapacitors.

In the contemporary landscape of technological advancements, the burgeoning demand for portable electronics and flexible wearable devices has necessitated the development of energy storage systems with superior volumetric performance. Tungsten oxide (WO3), known for its high density and theoretical capacitance, is a promising electrode material for supercapacitors. However, low conductivity and poor cycling stability are still the key bottlenecks for its application. Herein, a novel composite comprising hollow porous WO3 spheres (HPWS) derived by template method was electrostatic self-assembled on the surface of the Ti3C2Tx nanosheets. The resulting electrodes exhibited ultra-high volumetric capacitance of 1930 F cm-3 at 1 A g-1 and rate capability of 46% at 50 A g-1, attributed to enhanced ion accessibility from microporous structure and electron transport from conductive network of Ti3C2Tx even at a high packing density of 3.86 g cm-3. Utilizing HPWS/Ti3C2Tx as the negative electrode and porous carbon as the positive electrode, the assembled asymmetric supercapacitor achieved an energy density of 31 Wh kg-1 at a power density of 650 W kg-1 with over 107% capacitance retention after 5000 cycles. This work provides a promising approach for developing next-generation supercapacitors with ultra-high volumetric capacitance.

Electrospun metal-organic framework materials derived bimetallic oxides as high-efficiency anodes for lithium-ion battery

Energy devices are receiving more and more attention, and this is especially true for lithium-ion batteries. Moreover, applying novel nanostructures in multicomponent systems is a very effective way to promote the development of energy storage systems. This study synthesizes a nitrogen-doped carbon nanofiber encapsulating MOF-derived bimetallic oxide nanomaterial by combining electrospinning and MOF materials. Nitrogen-doped carbon nanofibers are porous and highly conductive, providing structural stability, a practical pathway for lithium ion diffusion, and an essential channel for rapid charge transfer during cycling. The bimetallic oxides derived from the MOF materials provide sufficient space for fast reaction sites and mitigate volume expansion during cycling. When the composite material FNO@NCNFs is used as the anode material for lithium batteries, its reversible capacity is maintained at 1105.4 mAh g−1 after 100 cycles at a current density of 0.1 A g−1. Its capacity reaches 748.5 mAh g−1 after 900 cycles at a current density of 1 A g−1, and at the same time, it exhibits excellent cycling stability, with the coulombic efficiency remaining above 98 %. The material also exhibits a small ion transfer resistance and good rate performance. The structural design approach based on combining MOFs with electrospinning in this study will provide new insights into the design and development of materials for advanced energy storage applications.

Experimental study on effect of cyclic gas pressure on mechanical and acoustic emission characteristics of salt rock

The utilization of renewable resources like wind and solar energy has led the Chinese government to prioritize the development of energy storage systems, garnering significant attention for salt cavern compressed air energy storage (CAES) technology. The stability of the surrounding rock in salt caverns is critical for ensuring sustained operation. By conducting mechanical tests on salt rock under fixed axial and confining pressures with cyclic gas pressure, the mechanical behavior and acoustic emission characteristics of salt rock under the influence of gas pressure were analyzed. The mechanical and acoustic emission characteristics of salt rock were analyzed. The results indicated that the triaxial compressive strength of salt rock negatively correlated with constant gas pressure. Both radial and axial strains demonstrated distinct phases: deceleration, steady-state, and acceleration. The steady-state creep rate of axial strain and the lower limit of cyclic gas pressure can be fitted in the form of an exponential function. The number of cyclic air pressure cycles decreased as the lower limit of cyclic air pressure increased. Acoustic emission count was used to define the damage variables, clarifying the formation and accumulation of salt rock damage in each stage, distinguishing the growth rates of damage during loading and unloading. It was observed that the higher the lower limit of cyclic air pressure, the quicker the damage accumulated with cycling. During the test, the absolute energy of the acoustic emissions from the salt rock conformed to a damped power-law distribution. The power-law distribution index γ of the absolute energy of acoustic emissions shifted with the number of cyclic air pressure cycles, and the sudden decrease of the distribution index γ plays a certain early warning role for the failure of salt rock.

A comprehensive survey of the application of swarm intelligent optimization algorithm in photovoltaic energy storage systems

With the rapid development of renewable energy, photovoltaic energy storage systems (PV-ESS) play an important role in improving energy efficiency, ensuring grid stability and promoting energy transition. As an important part of the micro-grid system, the energy storage system can realize the stable operation of the micro-grid system through the design optimization and scheduling optimization of the photovoltaic energy storage system. The structure and characteristics of photovoltaic energy storage system are summarized. From the perspective of photovoltaic energy storage system, the optimization objectives and constraints are discussed, and the current main optimization algorithms for energy storage systems are compared and evaluated. The challenges and future development of energy storage systems are briefly described, and the research results of energy storage system optimization methods are summarized. This paper summarizes the application of swarm intelligence optimization algorithm in photovoltaic energy storage systems, including algorithm principles, optimization goals, practical application cases, challenges and future development directions, providing new ideas for better promotion and application of new energy photovoltaic energy storage systems and valuable reference.

Advances in layered transition metal oxide cathodes for sodium-ion batteries

The rapid rise of renewable energy technology has greatly promoted the development of energy storage systems. Breaking decades of stagnation, sodium-ion batteries (SIBs) have now regained momentum in the field of energy storage and they are considered as a low-cost alternative to lithium-ion batteries. The search for suitable materials to reversibly host sodium ions has become a focal point in SIB field. Layered transition metal oxide (NaxTMO2) as the cathode material has attracted increasing attention due to its simple structure, facile synthesis, and high operating potential. Nevertheless, NaxTMO2 still faces severe challenges, including irreversible phase transitions, storage instability, insufficient performance, etc. This work provides a comprehensive review of NaxTMO2 as the cathode material for SIBs, analyzes the challenges encountered by NaxTMO2, and summarizes effective improvement strategies. Strategies including doping, composite cathode materials, high-entropy materials and microstructural modulation can effectively guide the design of NaxTMO2 with excellent performance. SIBs are bound to play a positive role in the new round of energy revolution.

Battery Energy Storage Systems: A Review of Energy Management Systems and Health Metrics

With increasing concerns about climate change, there is a transition from high-carbon-emitting fuels to green energy resources in various applications including household, commercial, transportation, and electric grid applications. Even though renewable energy resources are receiving traction for being carbon-neutral, their availability is intermittent. To address this issue to achieve extensive application, the integration of energy storage systems in conjunction with these resources is becoming a recommended practice. Additionally, in the transportation sector, the increased demand for EVs requires the development of energy storage systems that can deliver energy for rigorous driving cycles, with lithium-ion-based batteries emerging as the superior choice for energy storage due to their high power and energy densities, length of their life cycle, low self-discharge rates, and reasonable cost. As a result, battery energy storage systems (BESSs) are becoming a primary energy storage system. The high-performance demand on these BESS can have severe negative effects on their internal operations such as heating and catching on fire when operating in overcharge or undercharge states. Reduced efficiency and poor charge storage result in the battery operating at higher temperatures. To mitigate early battery degradation, battery management systems (BMSs) have been devised to enhance battery life and ensure normal operation under safe operating conditions. Some BMSs are capable of determining precise state estimations to ensure safe battery operation and reduce hazards. Precise estimation of battery health is computed by evaluating several metrics and is a central factor in effective battery management systems. In this scenario, the accurate estimation of the health indicators (HIs) of the battery becomes even more important within the framework of a BMS. This paper provides a comprehensive review and discussion of battery management systems and different health indicators for BESSs, with suitable classification based on key characteristics.

Carbon Covering Method to Enhance the Storage Capacity of Materials Belonging to the Conversion and Alloy Storage Types

AbstractDriven by the development of energy storage systems (EESs), finding alternative anode materials forlithium‐ion batteries to replace the general carbon materials is becoming a hot research topic in the world. Using the metal oxides, metal sulfides, metal phosphides, metal selenides belonging to the conversion type and Sn, Sb, Bi, Ge, P and Si belonging to the alloy storage type seems to be a preferred option. Nevertheless, the demerits such as volume expansion and bad conductivity of alternative materials restrict their practical application. Carbon covering is an efficacious strategy to deal with the aforementioned issues because it can restrict the volume expansion and improve the conductivity of the composite materials effectively. This present review paper comprehensively describes the suitable carbon resources and preparation methods for expanding the practical applications of materials belonging to the conversion type and ally type in fabrications of negative electrodes.

Photovoltaic output power estimation model based on multi-meteorological variable dimension reduction and improved variational mode decomposition algorithm

ABSTRACT The instability and intermittence of photovoltaic (PV) power generation challenge the large-scale integration of PV power generation systems into the power grid and the development of energy storage systems. To accurately predict the output power of PV power generation, a power prediction model based on the optimized variational modal decomposition (OVMD)-adaptive t-distribution sparrow search algorithm (tSSA)-least squares support vector machine (LSSVM) algorithm was built. The performance of the model was then verified by three-year meteorological data and real-time PV output power data of two different climatic regions in China. The mean absolute percentage error (MAPE) and root mean square error (RMSE) of this model were less than 3.1% and 0.40, respectively, and the determination coefficient (R2) of this model was greater than 95%. Moreover, the prediction accuracy was greatly improved compared to models based on the support vector machine (SVM), LSSVM, variational modal decomposition (VMD)-LSSVM, and VMD-SSA-LSSVM algorithms. Finally, by performing dimension reduction of meteorological variables related to PV output power, the performance of the proposed OVMD-tSSA-LSSVM model was further improved.

DESIGN OF HIGHLY EFFICIENT WATER PASSAGE OF PUMP-TURBINE

The problem of the need to develop renewable energy sources as a way to save the energy supply and energy independence of Ukraine by changing the consumption of carbohydrates is considered. It is shown that the development of Ukrainian renewable energy must occur in parallel with the development of energy storage systems and balancing of the energy system. The most effective system for storing energy and balancing the energy system is pumped storage power stations (PSPS). The work shows that the design of a highly effective equipment of a hydroelectric power plant depends on the correct selection of the element geometry of the pump-turbine water passage. Therefore, it is possible to ensure the necessary level of energy characteristics of hydraulic equipment. A method of dimensionless average parameters was established, which allows even at the initial stages of designing new reversible hydraulic machines to determine the optimal geometry of the watter passage elements. This method showed good results during the numerical research of Francis hydraulic turbines at a wide range of heads, as well as reversible hydromachines at heads of 300–500 m. Using expressions that establish the connection of hydrodynamic characteristics with dimensionless complexes, three variants of the flow part of the high-pressure pump-turbines (ORO500) were investigated. Based on the obtained results, a significant influence of the geometry on the hydraulic indicators of the machine was noted. The distribution of energy losses in the inlet, blade system and outlet was analyzed. The greatest energy losses occur in the inlet of the pump-turbines. To increase the energy and kinematic indicators of the ORO500 pump-turbines, the geometry of the feed elements, as well as the spiral casing and stator, was changed. Variants for improving the parameters in the elements of the supply of the water passage of the pump-turbine are proposed.

Recent Advances in Bromine Complexing Agents for Zinc–Bromine Redox Flow Batteries

The development of energy storage systems (ESS) has become an important area of research due to the need to replace the use of fossil fuels with clean energy. Redox flow batteries (RFBs) provide interesting features, such as the ability to separate the power and battery capacity. This is because the electrolyte tank is located outside the electrochemical cell. Consequently, it is possible to design each battery according to different needs. In this context, zinc–bromine flow batteries (ZBFBs) have shown suitable properties such as raw material availability and low battery cost. To avoid the corrosion and toxicity caused by the free bromine (Br2) generated during the charging process, it is necessary to use bromine complexing agents (BCAs) capable of creating complexes. As an overview, the different BCAs used have been listed to compare their behavior when used in electrolytes in ZBFBs. In addition, the coulombic and energy efficiencies obtained have been compared.

Electrification of Motorway Network: A Methodological Approach to Define Location of Charging Infrastructure for EV

Environmental issues have reached global attention from both political and social perspectives. Many countries and companies around the world are adopting measures to help change current trends. Awareness of decarbonization in the transportation sector has led to an increasing development of energy storage systems in recent years, especially for ground vehicles. Batteries, due to their high efficiency, are one of the most attractive energy storage systems for vehicle propulsion. As for road vehicles, the growing interest in Electric Vehicles (EVs) is motivated by the fact that they reduce local emissions compared to traditional Internal Combustion Engine (ICE) vehicles. The purpose of the paper is to present a study on how to plan and implement vehicle charging infrastructure on motorways. In particular, a specific road in Italy is analyzed: the motorway A1 from Milan to Naples with a length of about 800 km. This motorway can be considered representative because it passes through some of Italy’s most important cities and regions and may represent the backbone of Italy. A useful model for defining the optimal location of electric vehicle charging stations is presented within the paper. Starting with the data on the average daily traffic flows passing through the main nodes of the motorways section, the demand for the potential vehicles needed to define the number and dimension of charging stations and provide an adequate supply is estimated. The analysis was performed considering five-time horizons (year 2022 to year 2025) and four Scenarios involving the installation of 4, 8, 16, and 32 Charging Stations (CSs) in each service area, respectively.

Development of Energy Storage Systems for High Penetration of Renewable Energy Grids

As the proportion of renewable energy generation systems increases, traditional power generation facilities begin to face challenges, such as reduced output power and having the power turned off. The challenges are causing changes in the structure of the power system. Renewable energy sources, mainly wind and solar energy cannot provide stable inertia and frequency regulation capability. Ultimately, the power system’s emergency response capability to face an N-1 is reduced, which leads to a reduction in system stability. Therefore, the application technology of the battery energy storage system is used to support the impact of changes in the new power system structure. This paper designed control technologies based on the WECC second-generation generic model, namely, dynamic regulation, steady regulation, and virtual inertia regulation. The models and control strategies are verified on Taiwan’s 2025 power system target conditions, which consider the expected capacities for battery energy storage systems, and renewable energy sources with different load and N-1 fault levels. According to the simulation results, the capabilities of the RoCoF limitation, frequency nadir, frequency recovery, and system oscillation regulation are evaluated in the proposed strategies. Finally, the analysis results can help power operators make informed decisions when selecting and deploying battery energy storage systems.

(Invited) Open-Source Software and Open Data to Accelerate the Development of Energy Storage Systems

Many of the products we use in our daily lives, ranging from smartphones to web servers to cars, are based on a significant amount of open-source software. This approach has enabled standardization and rapid innovation in the tech industry. However, energy storage systems are typically not standardized in terms of components or software, leading to replicated development efforts across companies and significant balance of system costs. This talk will explore various efforts to publicly release data, software, and hardware to accelerate the development of energy storage systems. Examples include Battery Archive, the first public site for sharing battery data across institutions; control software for hybrid-batteries, available on GitHub; and a standard rack design for operating new batteries. These efforts will be described in the context of the need for physics-model driven battery operation and control of different types of batteries.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Peroxide Formation for Voltage Hysteresis in O2-Type Lithium-Rich Layered Oxides

Development of energy storage systems with high energy density is of vital importance for realizing a sustainable society. Although lithium-ion batteries (LIBs) are the state-of-the-art energy storage technology, their energy density is limited in part by the specific capacity of the positive electrode (cathode) materials. For example, conventional cathode materials, i.e., layered transition-metal oxides LiMO2 (M = transition metal), deliver a modest capacity of approximately 160 mAh/g, where the dominant mechanism of charge compensation for lithium-ion (de)intercalation is the valence change of the transition metal. Further increase in the cathode capacity requires an additional redox center.Integrating an anionic-redox (or oxygen-redox) capacity with the conventional cationic-redox capacity is a promising strategy for large-capacity battery cathodes exceeding present technical limits. However, most oxygen-redox cathodes exhibit a large charge/discharge voltage hysteresis (> 0.5 V), resulting in poor energy efficiency and impractical implementation. Considering immediate electron transfer (O2– → O– + e –) against subsequent structural deformation (O–O dimerization), the overall hypothetical mechanism of the oxygen-redox reactions is described as a square scheme (Figure 1) 1: if an oxidized oxide ion (O–) is stable, it directly contributes to a non-polarizing discharge capacity (nonpolarizing O redox).2 Meanwhile, unstable O– dimerize to form stable peroxo-like O2 2–, which may be accelerated by cation migration. The O2 2– dimers provide a polarizing discharge capacity (polarizing O redox) and an unstable reduced dimer (e.g., O2 4–) decomposes to O2–. The O–O dimerization is prone to result in release of O2 gas (O2 evolution) by their excessive oxidation. However, experimental verification of the square scheme is limited in part due to complicated structural changes during the oxygen-redox reactions. For example, O3-type Li1.2Ni0.2Mn0.6O2 (O3: lithium ions occupy octahedral sites between the MO2 layers, and the packing arrangement of the oxide ions is ABCABC) exhibits irreversible structural degradation such as layered-to-spinel transformation and surface cation densification upon cycling.In this work, we focus on O2-type lithium-rich layered transition-metal oxides that possess structural integrity against the oxygen-redox reactions (O2: lithium ions occupy octahedral sites between the MO2 layers and the packing arrangement of the oxide ions is ABCBA). O2-type Li1.12–y Ni0.17Mn0.71O2 delivers a large reversible capacity greater than 200 mAh/g with minimal voltage decay and capacity fading upon cycling. Combination of X-ray absorption/emission spectroscopy, magnetic susceptibility measurements, and density functional theory calculations indicates bond-forming 2O– → O2 2– and bond-cleaving O2 4– → 2O2– processes. These results emphasize the importance of suppressing the formation of O2 2– and maximizing the contribution of the nonpolarizing O2–/O– redox couple to develop energy-efficient oxygen-redox battery electrodes. Furthermore, based on the electrochemical kinetic analysis, particularly for the 2O2– → O2 2– transformation, technical strategies to quantify non-polarizing and energy-efficient oxygen redox will be discussed.References M. Okubo, et al., Acc. Mater. Res. 2021, 3, 33–41.A. Tsuchimoto, et al., Nat. Commun. 2020, 12, 63.K. Kawai, et al., Energy Environ. Sci. 2022, 15, 2591–2600. Figure 1

Investigating Intercalation of Chloroaluminate Anions in Graphene-Based Materials for Rechargeable Aluminum-Ion Batteries

Development of energy storage systems with high energy and power density, high safety, long cycle life, and low cost is crucial for various applications, including portable electronics and grid storage of renewable energies. Among various battery technologies, rechargeable aluminum ion batteries are particularly attractive due to the abundance, low cost, and safety of aluminum. However, unlike lithium ion batteries, many aspects of the fundamental intercalation processes and dynamics in these aluminum-based battery systems remain unresolved. In this study, we investigate the intercalation of chloroaluminate ions in atomically thin carbon cathodes using mesoscopic devices for charge transport and operando optical microscopy. These measurements provide insights into the energetics and dynamics of intercalation processes in atomically thin samples. We compare the atomically thin single crystal measurements to the cycling response of a high-performance rechargeable aluminum ion battery consisting of a few-layer graphene–multiwall carbon nanotube composite cathode. Our findings show that these nano-composites exhibit a high specific capacity and cyclic stability at high current densities, with a ~3-fold improvement in overall ion diffusivity in the aluminum ion battery. However, the battery cells still exhibit chloroaluminate diffusivities less than ~1% of those in mesoscopic single crystals. Our results highlight the distinction between intrinsic and ensemble electrochemical behavior in aluminum-based batteries and demonstrate that engineering ion transport to enhance diffusivity in these devices can lead to significant improvements in battery performance.

A Scalable Electronic-Embedded Transformer, a New Concept Toward Ultra-High-Frequency High-Power Transformer in DC–DC Converters

The demand for high-power and high-density isolated dc-dc converter is driven by the rapid development of energy storage system, data center power supplies and transportation electrification. However, designing a high-power and high-frequency transformer presents significant challenges due to the trade-off between thermal management, leakage inductance minimization, and insulation requirements. In order to overcome this trade-off between power rating and operation frequency, a scalable electronic-embedded transformer (EET) is proposed with a low voltage bridge integrated into the transformer windings. The EET addresses the challenge through its simple open-loop control and natural current sharing, enabling easy parallel connection and scaling to different power ratings. Based on this concept, a bi-directional EET-based dc transformer (EET-DCX) is proposed to solve the transformer-level paralleling and resonant point shift issues in traditional LLC-DCX designs. By employing the embedded full bridge, the EET-DCX effectively cancels out the impedance of the leakage inductance, ensuring optimal operation at any frequency. Additionally, the EET-DCX retains the inherent advantages of the LLC-DCX, such as load-independent voltage gain, simple open-loop control, full load range zero voltage switching (ZVS), and low circulating current. Leveraging these advantages, the proposed EET-DCX solution has the potential to push the boundaries of transformer performance to the MHz operation frequency range with hundreds of kilowatts power capability. To validate these merits, a 12 kW 500 kHz EET-DCX with four planar EET units was built. This article is accompanied by two videos demonstrating the dynamic load changing and frequency changing test.

Protic dialkylammonium-based ionic liquids as promising solid-solid phase change materials for thermal energy storage: Synthesis and thermo-physical characterization

The widespread deployment of renewable energies such as solar and wind implies the parallel development of energy storage systems to deal with their intermittency. Storing renewable energy as thermal energy is one of the alternatives under constant research. In this regard, phase change materials (PCMs) are able to store large amounts of energy at a nearly constant temperature in the form of latent heat. Nevertheless, most of these PCMs undergo solid-liquid transitions, which hamper their implementation due to leaking issues, forcing the need for containment and increasing the final cost of the TES system.Therefore, a class of PCMs possessing solid-solid transitions has emerged to avoid these problems, the so-called organic ionic plastic crystals (OIPCs). Currently, the scientific literature and the number of OIPCs available for TES are rather scarce. Herein, we present the synthesis, the structural, and the thermo-physical characterization of nine OIPCs based on the dioctylammonium cation combined with different organic and inorganic acids as the anions. Particular attention has been paid to the most characteristic thermal properties of PCMs (latent heat, transition temperature, subcooling, thermal conductivity, and energy storage density), evaluating their thermal stability and the reliability of the most promising materials over thermal cycling as well. Among the prepared OIPCs, 3 of them, [DOA][NO3], [DOA][Cl], and [DOA][FOR], exhibited promising properties with remarkable solid-solid transition enthalpies of 156.6 J/g (at 41.4 °C), 101.2 J/g (at 20.0 °C) and 58.4 J/g (at 29.7 °C), respectively. These 3 OIPCs showed high potential to be used and integrated as PCMs in TES systems at temperatures below 45 °C.

Economic evaluation of energy storage integrated with wind power

Energy storage can further reduce carbon emission when integrated into the renewable generation. The integrated system can produce additional revenue compared with wind-only generation. The challenge is how much the optimal capacity of energy storage system should be installed for a renewable generation. Electricity price arbitrage was considered as an effective way to generate benefits when connecting to wind generation and grid. This wind-storage coupled system can make benefits through a time-of-use (TOU) tariff. A proportion of electricity is stored from the wind power system at off-peak time (low price), and released to the customer at peak time (high price). Thus, extra benefits are added to the wind-storage system compared with wind-only system. A Particle Swarm Optimization (PSO) algorithm based optimization model was constructed for this integrated system including constraints of state-of-charge (SOC), maximum storage and release powers etc. The proposed optimization model was to obtain the optimal capacity of energy storage system and its operation control strategy of the storage-release processes, to maximize the revenue of the coupled system considering the arbitrage. Furthermore, the energy storage can provide reserve ancillary services for the grid, which generates benefits. The benefits of energy storage system through reserve ancillary services were also calculated. A case study was analyzed with respect to yearly wind generation and electricity price profiles. The benefit compared with no energy storage scenario was calculated. The impact of the energy storage efficiency, cost and lifetime was considered. The sensitivity and optimization capacity under various conditions were calculated. An optimization capacity of energy storage system to a certain wind farm was presented, which was a significant value for the development of energy storage system to integrate into a wind farm.

Printed Electronics in Radiofrequency Energy Harvesters and Wireless Power Transfer Rectennas for IoT Applications

AbstractThe Internet of Things is currently one of the fastest‐growing branches in electronics. The development of energy storage systems and the miniaturization of dedicated printed circuit boards significantly influence that growth. However, the need for batteries and traditional printed circuit boards still limits devices' minimum size, weight, and cost, narrowing the application area. Energy harvesters and wireless power transfer systems fabricated with printed electronics can significantly reduce such devices' weight, size, and cost. Printed electronics technology provides scalable tools for many electronics applications, shortening the validation time and enabling new low‐cost or disposable solutions on lightweight and flexible substrates embedded inside 3D printed structures and directly on device housings. Energy harvesting and wireless power transfer systems in electronic devices can provide enough power to minimize battery capacity and size or even eliminate the need for batteries in low‐power applications. This review presents an adaptation of printed electronics technology in the fabrication of radio frequency energy harvesters and wireless power transfer rectennas for IoT applications. Last, perspectives for development towards greater integration with microsystems, transient electronics with ecofriendly materials, adaptation for next‐generation telecommunication systems, and 3D structural electronics solutions are briefly discussed.