Grid-scale Energy Storage Systems Research Articles

Material Design of Aqueous Redox Flow Batteries: Fundamental Challenges and Mitigation Strategies.

Redox flow batteries (RFBs) are critical enablers for next-generation grid-scale energy-storage systems, due to their scalability and flexibility in decoupling power and energy. Aqueous RFBs (ARFBs) using nonflammable electrolytes are intrinsically safe. However, their development has been limited by their low energy density and high cost. Developing ARFBs with higher energy density, lower cost, and longer lifespan than the current standard is of significant interest to academic and industrial research communities. Here, a critical review of the latest progress on advanced electrolyte material designs of ARFBs is presented, including a fundamental overview of their physicochemical properties, major challenges, and design strategies. Assessment methodologies and metrics for the evaluation of RFB stability are discussed. Finally, future directions for material design to realize practical applications and achieve the commercialization of ARFB energy-storage systems are highlighted.

High-Rate and Long-Cycle Cathode for Sodium-Ion Batteries: Enhanced Electrode Stability and Kinetics via Binder Adjustment.

Sodium-ion batteries (SIBs) are heralded as promising candidates for grid-scale energy storage systems due to their low cost and abundant sodium resources. Excellent rate capacity and outstanding cycling stability are always the goals for SIBs. Up to now, nearly all attention has been focused on the control of morphology and structure of electrode materials, but the influence of binders on their performance is neglected, especially in cathode materials. Herein, using Na3V2(PO4)2O2F (NVPOF) as a cathode material, the influence of four different binders (sodium alginate, SA; carboxymethylcellulose sodium, CMC; poly(vinylidene fluoride), PVDF; and poly(acrylic latex), LA133) on its electrochemical performance is studied. As a result, when using SA as the binder, the electrochemical performance of the NVPOF electrode is improved significantly, which is mainly because of the high water solubility, rich carboxyl and hydroxyl groups, and high adhesive and cohesive properties of the SA binder, leading to the uniform distribution of active materials NVPOF and carbon black in electrodes, good integrity, low polarization, and superior kinetic properties of the NVPOF electrodes, as demonstrated by scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic intermittent titration technique. More importantly, when coupled with a hard carbon anode, the fabricated sodium-ion full cells also exhibit excellent rate performance, thus providing a preview of their practical application. This work shows that the battery performance can be improved by matching suitable binder systems, which is believed to have great importance for the further optimization of the electrochemical performance of SIBs.

Iron-Doped Sodium Vanadium Oxyflurophosphate Cathodes for Sodium-Ion Batteries-Electrochemical Characterization and In Situ Measurements of Heat Generation.

Sodium-ion batteries (NaIBs) are increasingly being envisioned for grid-scale energy-storage systems because of cost advantages. However, implementation of this vision has been challenged by the low-energy densities delivered by most NaIB cathodes. Toward addressing this challenge, the authors report the synthesis and characterization of a new iron-doped Na3Fe0.3V1.7O(PO4)2F2 cathode using a novel facile hydrothermal route. The synthesized material was characterized using scanning electron microscopy, X-ray diffraction, and Mössbauer spectroscopy techniques. The obtained discharge capacity in the half-cell configuration lies from 119 to 125 to 130 mA h/g at C/10 while tested using three different electrolyte formulations, dimethyl carbonate-ethylene carbonate (EC)-propylene carbonate (PC), diethyl carbonate-EC, and EC-PC, respectively. The synthesized cathodes were also evaluated in full-cell configurations, which delivered an initial discharge capacity of 80 mA h/g with NaTi2(PO4)3MWCNT as the anode. Ionic diffusivity and interfacial charge transfer kinetics were also evaluated as a function of temperature and sodium concentration, which revealed that electrochemical rate performances in this material were limited by charge-transfer kinetics. To understand the heat generation mechanism of the Na/Na3Fe0.3V1.7O(PO4)2F2 half-cell during charge and discharge processes, an electrochemical isothermal calorimetry measurement was carried out at different current rates for two different temperatures (25 and 45 °C). The results showed that the amount of heat generated was strongly affected by the operating charge/discharge state, C-rate, and temperature. Overall, this work provides a new synthesis route for the development of iron-doped Na3Fe0.3V1.7O(PO4)2F2-based high-performance sodium cathode materials aimed at providing a viable pathway for the development and deployment of large-scale energy-storage based on sodium battery systems.

FeS2@TiO2 nanorods as high-performance anode for sodium ion battery

Abstract Sodium-ion battery (SIB) is an ideal device that could replace lithium-ion battery (LIB) in grid-scale energy storage system for power because of the low cost and rich reserve of raw material. The key challenge lies in developing electrode materials enabling reversible Na+ insertion/desertion and fast reaction kinetics. Herein, a core-shell structure, FeS2 nanoparticles encapsulated in biphase TiO2 shell (FeS2@TiO2), is developed towards the improvement of sodium storage. The diphase TiO2 coating supplies abundant anatase/rutile interface and oxygen vacancies which will enhance the charge transfer, and avoid severe volume variation of FeS2 caused by the Na+ insertion. The FeS2 core will deliver high theoretical capacity through its conversion reaction mechanism. Consequently, the FeS2@TiO2 nanorods display notable performance as anode for SIBs including long-term cycling performance (637.8 mA·h·g−1 at 0.2 A·g−1 after 300 cycles, 374.9 mA·h·g−1 at 5.0 A·g−1 after 600 cycles) and outstanding rate capability (222.2 mA·h·g−1 at 10 A·g−1). Furthermore, the synthesized FeS2@TiO2 demonstrates significant pseudocapacitive behavior which accounts for 90.7% of the Na+ storage, and efficiently boosts the rate capability. This work provides a new pathway to fabricate anode material with an optimized structure and crystal phase for SIBs.

Reversible redox chemistry in azobenzene-based organic molecules for high-capacity and long-life nonaqueous redox flow batteries

Redox-active organic molecules have drawn extensive interests in redox flow batteries (RFBs) as promising active materials, but employing them in nonaqueous systems is far limited in terms of useable capacity and cycling stability. Here we introduce azobenzene-based organic compounds as new active materials to realize high-performance nonaqueous RFBs with long cycling life and high capacity. It is capable to achieve a stable long cycling with a low capacity decay of 0.014% per cycle and 0.16% per day over 1000 cycles. The stable cycling under a high concentration of 1 M is also realized, delivering a high reversible capacity of ~46 Ah L−1. The unique lithium-coupled redox chemistry accompanied with a voltage increase is observed and revealed by experimental characterization and theoretical simulation. With the reversible redox activity of azo group in π-conjugated structures, azobenzene-based molecules represent a class of promising redox-active organics for potential grid-scale energy storage systems.

A comparative study between ORC and Kalina based waste heat recovery cycles applied to a green compressed air energy storage (CAES) system

Intermittent nature of the generated power from renewable energy resources and a higher demand for electricity during peak demand periods have intensified the need for grid-scale energy storage systems. Compressed air energy storage system, owing to significant merits such as minimum geographical and environmental limits and high reliability, has attracted attention in recent years. To improve efficiency, its hybridization with various waste heat recovery cycles has been taken into the account. To provide the grid with further power during peak demand periods, organic Rankine and Kalina cycles are the most practical alternatives. Hence, the combination of a green compressed air energy storage with various low- and medium-temperature waste heat recovery cycles is analyzed in the present article to address the most feasible choice in diverse working conditions. The subcritical and supercritical organic Rankine cycles with different working fluids (R717, R1270, R290, and R1234yf), as well as two Kalina cycles (KCS11 and KCS34) are analyzed from the perspective of the first and second laws of thermodynamics and compared with each other. The results indicate that the energy and exergy round trip efficiencies can be improved by 1.69–2.67% and 1.70–2.69%, compared to the stand-alone compressed air energy storage. The supercritical organic Rankine cycle with R290 as the working fluid is the best alternative, which recovers the highest amount of wasted heat and improves the production capacity by 2.47%.

Enabling ultrahigh rate and capacity sodium metal anodes with lightweight solid additives

Sodium (Na) metal is a promising anode for grid-scale energy storage systems owing to its high theoretical capacity and low cost. However, severe Na dendrite growth during cycling causes unsatisfied performance and safety concerns. Herein, extremely stable Na metal anodes with superior capacity and ultrahigh-rate capability are achieved by employing lightweight nitrogen (N)-doped graphene microcubes as solid additives. The direct addition of the as-obtained microcubes into bulk Na not only facilitates homogenous Na plating, but also minimizes volume change during cycling. Consequently, with only 3 ​wt% addition of N-doped graphene microcubes, an extremely stable Na metal anode can be realized in additive-free carbonate electrolytes at an ultrahigh current density of 20 ​mA ​cm−2 with an ultrahigh capacity of 10 mAh cm−2 over 250 ​h. Full cells based on the Na anodes with the assistance of solid additives exhibit significantly improved electrochemical performance in carbonate electrolytes. This work can provide a viable pathway towards the realization of high-energy Na battery systems.

Electrochemical studies on symmetric solid-state Na-ion full cell using Na3V2(PO4)3 electrodes and polymer composite electrolyte

Ubiquitous low-cost sodium ore is abundant and increasingly of interest for sodium-based battery research for grid-scale energy storage systems. The conventional organic liquid electrolytes in currently used sodium-based batteries endure inflammability, thermal instability, and risk of safety issues. The recent trend in developing solid-state-Li batteries also thrives on exploring the all-solid-state Na battery. Herein, we report a solid-state Na-ion full cell working at room temperature using a polyvinylidene fluoride (PVDF)-based composite polymer electrolyte and NaZr2(PO4)3-structured Na3V2(PO4)3 (NVP) electrode. PVDF-based composite polymer electrolyte (CPE) with NaCF3SO3 salt and SiO2 filler displays high conductivity with electrochemical stability. The symmetric solid-state full cell delivers a specific capacity of 76 mA h g−1 at 0.5C rate, and a specific energy of 126 W h kg−1 based on the total mass of the NVP cathode only. The solid-state Na-ion full cell can retain 70% of its initial specific capacity after 100 continuous charge-discharge cycles.

Levelised Cost of Storage (LCOS) analysis of liquid air energy storage system integrated with Organic Rankine Cycle

Liquid Air Energy Storage (LAES) is a unique decoupled grid-scale energy storage system that stores energy through air liquefaction process. In order to further increase the utilization ratio of the available waste heat discharged by the air compression and not effectively recovered during the discharge phase, the authors have previously investigated the thermodynamic feasibility of different integrated LAES systems and promising results have been shown for the LAES coupled with Organic Rankine Cycle (integrated system LAORC). In order to assess the economic feasibility of the integrated system, this paper presents a techno-economic comparative analysis of the stand-alone LAES and the integrated system LAORC. The LAES systems have been designed by means of the quasi non-dimensional maps developed by the authors and the Levelised Cost of Storage (LCOS) has been employed to evaluate the economic viability of the investment by also comparing the LAES with Li-ion batteries. The results show that the stand-alone LAES system is generally cost-competitive with Li-ion batteries and even more in LAORC integrated system with the advantage of additional power output from the ORC. When LAES is operated in cogenerative configuration, the LAORC integrated system produces the most significant results decreasing the LCOS by 10%.

Fast Frequency Response From Energy Storage Systems—A Review of Grid Standards, Projects and Technical Issues

Electric power systems foresee challenges in stability due to the high penetration of power electronics interfaced renewable energy sources. The value of energy storage systems (ESS) to provide fast frequency response has been more and more recognized. Although the development of energy storage technologies has made ESSs technically feasible to be integrated in larger scale with required performance, the policies, grid codes and economic issues are still presenting barriers for wider application and investment. Recent years, a few regions and countries have designed new services to meet the upcoming grid challenges. A number of grid-scale ESS projects are also implemented aiming to trial performance, demonstrate values, and gain experience. This paper makes a review on the above mentioned aspects, including the emerging frequency regulation services, updated grid codes and grid-scale ESS projects. Some key technical issues are also discussed and prospects are outlined.

Composite sodium metal anodes for practical applications

With its high theoretical capacity (1165 mA h g−1), low reduction potential (−2.71) and abundant resources in the earth's crust, Na anode exhibits great potential in grid-scale energy storage systems and extensive application of electric vehicles.

Mechanistic investigation of silver vanadate as superior cathode for high rate and durable zinc-ion batteries

Rechargeable aqueous Zn-ion batteries have shown considerable potential for stationary grid-scale energy storage systems owing to their characteristics of low cost and non-pollution. Nevertheless, the development of high-performance cathode materials is still a formidable challenge. In this work, for the first time, we report a superior silver vanadate (β-AgVO3) cathode for Zn-ion batteries, and demonstrate the fundamental Zn2+ storage mechanism in detail. In sharp contrast to the previously-reported layered vandium-based materials, the β-AgVO3 cathode experiences an initial phase transition to form a layered Zn3V2O7(OH)2·2H2O through a displacement/reduction reaction of Zn2+/Ag+ in the first discharge process. The in situ generated Ag0 along with the residual Ag+ and structural water within the framework afford high electronic/ionic conductivity, thus enabling enhanced Zn2+ intercalation/deintercalation kinetics in the layered phase. As a consequence, the cathode can deliver remarkable rate performance (103 mAh g−1 at 5000 mA g−1) and long-term cycling stability (95 mAh g−1 after 1000 cycles at 2000 mA g−1). The present study offers a totally new insight into the exploration of non-layered-structured vandium-based cathodes for high performance Zn-ion batteries.

An optimal allocation and sizing strategy of distributed energy storage systems to improve performance of distribution networks

Abstract The allocation of grid-scale energy storage systems (ESSs) can play a significant role in solving distribution network issues and improving overall network performance. This paper presents a strategy for optimal allocation and sizing of distributed ESSs through P and Q injection by the ESSs to a distribution network. The investigation is carried out in a renewable-penetrated (wind and solar) medium voltage IEEE-33 bus distribution network for two different scenarios: (1) using a uniform ESS size and (2) using non-uniform ESS sizes. DIgSILENT PowerFactory is used for system modeling and testing, and simulation events are automated using Python scripting. A hybrid meta-heuristic optimization algorithm such as the fitness-scaled chaotic artificial bee colony algorithm is applied to optimize parameters of the objective function. The artificial bee colony algorithm is also applied to justify the results attained from the fitness-scaled chaotic artificial bee colony algorithm. A performance comparison, in relation to proposed PQ injection approach with previously applied P injection technique, is presented. The obtained results suggest that the proposed PQ injection-based ESS placement strategy performs better than the P injection-based approach, which can significantly improve distribution network performance by minimizing voltage deviation, power losses, and line loading.

Life Prediction of Lithium Ion Battery for Grid Scale Energy Storage System

As renewable energy with large output fluctuation increases, adoption of a large power storage system in which lithium ion secondary batteries are series-parallelized has been started for stabilization of grid power. However, stationary storage systems may be charged and discharged under more severe conditions than batteries for electric vehicles, and may deteriorate in a short period of time. In this research, while analyzing the change of capacity and internal resistance of the lithium ion secondary battery which uses LFP for the cathode and carbon anode. We estimated the life when charging and discharging under the conditions of ancillary service*, and considered the proposed measures for prolonging the life. * ancillary service; A power adjustment method for stabilizing grid transmission Experiment A sample cell using an electrode (57 mm × 40 mm) including LiFePO4 for the positive electrode and carbon for the negative electrode was used. As evaluation methods, temperature and charge / discharge cycle tests with different charge / discharge rates and calendar life tests were conducted to analyze cycle characteristics and time characteristics of capacity and internal resistance. Results and Discussion 2.1 Cell performance The LFP cell produced in this study had an average voltage of 3.05 V (during 1 C discharge), an initial capacity of 1.0 Ah (during 1 C discharge), and a DC resistance of 16 mΩ (SOC 50%). When 1 C charge and discharge were repeated in the initial cell, the temperature rose to 31.1 °C. under natural cooling conditions of 24.9 ° C. outside temperature. 2.2 Degradation characteristics The capacity decrease is highly dependent on SOC, and in the state of 90% of SOC, the capacity decrease was about twice as fast as 50% of SOC. On the other hand, the increase in resistance was highly temperature-dependent, and the capacity decrease was about twice as fast as at 25 ° C. at 45 ° C. conditions. Also, multiple degradation mechanisms exist because at least two or more inflection points exist, not following the 1/2 power of time, which is the degradation tendency of a general lithium ion secondary battery. 2.3 Life prediction of LIB for grid scale energy storage system There are many ways to operate the stationary storage system, but as a power adjustment method to stabilize power transmission of the system, the result of predicting the degradation behavior when the battery is operated under the test condition of ancillary service reported by PJM. It has been found that if the number of cells in parallel is reduced to increase the output power per unit cell, the deterioration is accelerated due to the influence of the temperature rise of the cells. Figure 1

1D Buliding Block Strategies for High Energy Density Li-Ion Batteries

Ever-increasing demand for high-performance portable electronics, electric vehicles (EVs) and grid-scale energy storage systems (ESSs) has been in relentless pursuit of advanced energy storage systems with reliable electrochemical properties. Among a vast variety of rechargeable power sources, undoubtedly, lithium-ion batteries have been most widespread and still garnered considerable attention due to their well-customized battery characteristics. From the electrode architecture point of view, most conventional electrodes are characterized with simple and random pile-up of electrode active materials, carbon powder conductive additives and polymer binders on top of metallic foil current collectors. Unfortunately, such a stereotyped electrode architecture often gives rise to non-uniform and sluggish electron/ion transport particularly in their through-thickness direction and is also vulnerable to structural disruption upon mechanical deformation. In particular, the poorly-developed electron/ion conduction pathways of the electrodes eventually provoke unwanted electrochemical polarization, which becomes more serious at harsh operating conditions such as high-mass loading electrodes and fast charge/discharge current densities that are urgently needed for high-energy EV batteries. Due to these unavoidable limitations, the conventional electrode architecture has posed a formidable challenge to sustainable progress of battery performance, thus pushing us to search for alternative solutions. Here, we demonstrate a new class of all-nanomat lithium-ion batteries (LIBs) based on one-dimensional (1D) building elements interweaved into heteronanomat skeletons. Among various electrode materials, silicon (Si), over-lithiated layered oxide (OLO) materials and redox-active organic materials are chosen as model systems to explore the feasibility of this new cell architecture and achieve unprecedented cell capacity. Nanomat electrodes, which are completely different from conventional slurry-cast electrodes, are fabricated through concurrent electrospinning (for polymeric nanofibers) and electrospraying (for electrode materials/carbon nanotubes (CNTs)). Electrode active material powders are compactly embedded in the spatially interweaved polymeric nanofiber/CNT heteromat skeletons, which play a crucial role in constructing three-dimensional (3D)-bicontinuous ion/electron transport pathways and in removing metallic foil current collectors. Driven by the aforementioned structural/chemical uniqueness, the all-nanomat electrodes show exceptional improvement in electrochemical performance as well as mechanical deformability, which lie far beyond the values achievable with conventional LIB technologies.

The Chemical Stability of Nasicon As a Solid Electrolyte for Seawater Batteries

Seawater batteries have attracted significant attention for use as grid-scale energy storage systems (ESSs) due to the effective utilization of abundant resources of seawater as a catholyte. Sodium ions in seawater selectively transfer through a solid electrolyte to the anode for saving the chemical energy. For the selective transfer of sodium ions, NASICON (Na3Zr2Si2PO12) electrolytes are one of the suitable candidates for the solid electrolyte to prevent a short circuit between the catholyte and anode. However, NASICON powder is known to be dissolved in water because of the structural instability, leading to catastrophic failure of the system, while NASICON solid electrolytes are stable in seawater during the battery operation. In this regard, we have carefully compared the stability of NASICON powder and pellets in both DI water and seawater associated with different degradation mechanism. Figure shows the structural stability of NASICON pellets after the immersion tests in DI water and seawater indicative of the chemical stability of NASICON in seawater. In addition, the electrochemical performance shows higher stability of the seawater-immersed electrolyte than the DI water-immersed electrolyte. The corresponding analyses are carried out to confirm the effect of the investigation. Furthermore, we have employed polymer coating methods to enhance stability and performance as a seawater battery system. The coating layer enables to prevent direct contact with seawater, resulting in longer stability during operation without compromising ionic conductivity. These results reveal that NASICON solid electrolytes can be operated in seawater with high stability and performance. Figure. The chemical stability comparison of NASICON in seawater and DI water References Mauvy, F., Siebert, E., & Fabry, P. (1999). Reactivity of NASICON with water and interpretation of the detection limit of a NASICON based Na+ion selective electrode. Talanta , 48(2), 293–303.Fuentes, R. O., Figueiredo, F., Marques, F. M. B., & Franco, J. I. (2001). Reaction of NASICON with water, Solid State Ionics , 263, 309–314.Kim, Y., Kim, H., Park, S., Seo, I., & Kim, Y. (2016). Na ion- Conducting Ceramic as Solid Electrolyte for Rechargeable Seawater Batteries. Electrochimica Acta , 191, 1–7.Jung, J. Il, Kim, D., Kim, H., Jo, Y. N., Park, J. S., & Kim, Y. (2017). Progressive Assessment on the Decomposition Reaction of Na Superionic Conducting Ceramics. ACS Applied Materials & Interfaces , 9(1), 304–310. Figure 1

Optimal allocation of distributed energy storage systems to improve performance and power quality of distribution networks

The placement of grid-scale energy storage systems (ESSs) can have a significant impact on the level of performance improvements of distribution networks. This paper proposes a strategy for optimal allocation of distributed ESSs in distribution networks to simultaneously minimize voltage deviation, flickers, power losses, and line loading. The optimal ESS allocation is investigated through the PQ injection (considering a variable power factor on the dispatch of ESSs) and the results are compared in terms of performance and power quality improvements. An IEEE-33 bus distribution system (medium voltage), having a high influence of renewable (wind and solar) distributed generation, is used as the test network. The overall investigation is conducted for two distinct scenarios: (1) applying a uniform ESS size and (2) applying non-uniform ESS sizes. DIgSILENT PowerFactory is used for developing, analyzing, and testing the system models. The fitness-scaled chaotic artificial bee colony optimization algorithm (a hybrid meta-heuristic technique) is applied to optimize parameters of the objective function. A Python script is used to automate simulation events in PowerFactory. The optimization results are verified through the application of the conventional artificial bee colony algorithm. Detailed simulation results imply that the proposed ESS allocation technique can successfully minimize voltage deviation, flicker disturbance, line loading, and power losses, and thereby significantly improve performance and power quality of a distribution network.

High-Safety Symmetric Sodium-Ion Batteries Based on Nonflammable Phosphate Electrolyte and Double Na3V2(PO4)3 Electrodes.

Sodium-ion batteries (SIBs) have been viewed as a promising candidate for grid-scale energy storage systems owing to their low cost and abundant Na resources. However, insufficient safety and poor cycling performance of current SIBs are hampering their implementation. Herein, we develop a symmetric SIB by employing Na3V2(PO4)3 as both cathode and anode along with the nonflammable triethyl phosphate dissolving 0.9 M NaClO4 as the electrolyte. The symmetric SIB demonstrates a superior rate capability (35.1 mA h g-1 at 32 C) and excellent cycling performance with a capacity retention of 88.9% after 500 cycles at 2 C. This work demonstrates a new avenue to construct safe and long-cycle-life SIBs with a simple electrode manufacturing process.

Mass Transport Characterization in Redox Flow Batteries Using Fluorescence Microscopy in Operando

Significant advancements in aqueous organic redox flow battery (RFB) chemistries are generating greater anticipation for grid scale energy storage systems. However, low power densities, driven in part by mass transport limitations within the cell stack, limit the performance of these systems. A detailed understanding of mass transport and electrochemical activity within the porous electrode would benefit all RFB chemistries, particularly those using aqueous organic electrolytes. In this study we use fluorescence microscopy to image fluid flow and electrochemical activity in operando using fluorescent tracer particles and redox-active aqueous-soluble quinones respectively. The fluorescence of the reduced quinone is used as a direct measure of local state of charge and the tracer particles allow measurements of local velocities and fluid streamlines. The combined approach illuminates the influence of the electrode architecture on electrochemical-flow processes, unveiling surprisingly heterogeneous behavior over length scales significantly larger then the average pore diameter. Several electrode styles are compared including papers, cloths and felts with an emphasis on mass transport characteristics impacting their performance. We will discuss further applications for this in operando technique and suggest potential electrode architectures to improve RFB performance as grid scale energy storage systems. Figure: (left) Strobe imaging of fluorescent tracer particles highlighting fluid streamlines in a woven carbon fiber electrode. (center) Colorized image of a fluorescent quinone electrolyte undergoing electrochemical reduction in operando. Image width is 2 mm highlighting the strikingly heterogeneous mass transport process. (right) particle tracking of fluorescent tracer particles providing insight into local velocity fields and fluid dead zones. Figure 1

Investment optimization of grid-scale energy storage for supporting different wind power utilization levels

With the large-scale integration of renewable generation, energy storage system (ESS) is increasingly regarded as a promising technology to provide sufficient flexibility for the safe and stable operation of power systems under uncertainty. This paper focuses on grid-scale ESS planning problems in transmission-constrained power systems considering uncertainties of wind power and load. A scenario-based chance-constrained ESS planning approach is proposed to address the joint planning of multiple technologies of ESS. Specifically, the chance constraints on wind curtailment are designed to ensure a certain level of wind power utilization for each wind farm in planning decision-making. Then, an easy-to-implement variant of Benders decomposition (BD) algorithm is developed to solve the resulting mixed integer nonlinear programming problem. Our case studies on an IEEE test system indicate that the proposed approach can co-optimize multiple types of ESSs and provide flexible planning schemes to achieve the economic utilization of wind power. In addition, the proposed BD algorithm can improve the computational efficiency in solving this kind of chance-constrained problems.