Energy Storage System Research Articles

Study of a Power Supply System Operation Based on Methane Generator Supported by an Energy Storage System, to Cover High Fluctuation Electrical Loads: Greenhouse Case Study

The operation of a greenhouse requires the consumption of high amounts of energy. The problem is strengthened by the energy crisis that characterizes our days. This article studies an energy management strategy based on the utilization of methane generators (MG) for energy saving in greenhouses. The management strategy includes covering the energy needs of a greenhouse unit (GHU) by directly injecting the energy produced by the generator units. If the energy produced from MG cannot meet the energy needs of the GHU, an energy storage system (ESS) or a backup (in case ESS is unavailable) is used to support the load, covering the gap between production and consumption. In case of excess energy, priority is given to charging the ESS, and the possible presence of excess energy is led to the network. The main objective of energy management is the optimal design of the MG-ESS system to minimize the possibility of energy excess and deficit. The analysis presented is based on actual GHU energy demand. The special feature of this load is the existence of strong daily fluctuations in energy consumption, especially during the summer months. This study presents a methodology for managing such loads with the main objective of maximizing the operating efficiency of MG. Briefly, this article brings a new look to the existing literature in the following areas: (I) a methodology for the efficient operation of methane generators in combination with ESS to cover both mild and intense power fluctuations has been developed, (II) The mapping of the load profile and its division into zones of different power levels providing the possibility of choosing different sizes of generators that will operate at their optimal power has been achieved and (III) a techno-economically optimal ESS to support the generators in meeting load needs and absorbing excess energy has been designed. The analysis based on the use of three different MGs in the three mapped load zones that will operate at constant power due to their support by an ESS led to the identification of the appropriate combination of MG-ESS for the autonomous operation of the GHU. The preliminary economic evaluation of the optimal MG-ESS combination based on LCOE showed that the proposed system (LCOE = 0.216 – 0.279) is competitive with the existing system (LCOE = 0.392) responsible for covering the load’s energy demand.

Role of metal-organic frameworks (MOFs) in electrochemical energy storage devices including batteries and supercapacitors

Abstract Better energy storage systems are becoming more and more in demand as electric cars, portable electronics, and renewable energy sources become more prevalent. Supercapacitors and batteries, such as lithium-ion batteries (LIBs), sodium-ion batteries (NIBs), lithium sulfur/air batteries, and lithium selenium batteries, are major components of these technologies; yet, stability, cycle life, and energy density are some of the challenges they face. MOFs have emerged as a new material that can solve the problems with unique structural properties. Large surface area and porosity are properties of MOFs which improve the energy density, life cycle and stability of energy storage devices when MOF are used as alectrode material in these devices.This paper analyzes and focuses on the application of MOFs in supercapacitors, LIBs, and SIBs, in which it emphasizes improvement in terms of stability and performance. This review article ends with an overview of the important challenges and the prospects for future research to fully meet the promise of Metal organic frameworks in energy storage applications.

Coassembly of Ultrathin Lithium with Dual Lithium-Free Electrodes for Long-Lasting Sulfurized Polyacrylonitrile Batteries.

With the rising demand for long-term grid energy storage, there is an increasing need for sustainable alternatives to conventional lithium-ion batteries. Electrode materials composed of earth-abundant elements are appealing, yet their lithiated-state stability hampers direct battery applications. In this paper, we propose for the first time a concept of coassembling ultrathin lithium with both lithium-free cathodes and lithium-free anodes to build high-energy, long-lasting, safe, and low-cost batteries tailored for long-duration energy storage. As a proof-of-concept, we selected sulfurized polyacrylonitrile (SPAN) as the lithium-free cathode and graphite/silicon-carbon (Gra/SiC) as the lithium-free anode, both of which are earth abundant. This newly conceptualized configuration not only successfully prevents overprelithiation but also exhibits superior energy density (293 Wh kg-1 and 363 Wh kg-1, respectively), excellent cycle stability (1,800 cycles), and benefit of low cost and environmental sustainability. This approach fosters new opportunities for the development of lithium-free, earth-abundant electrode batteries, spurring the development of sustainable and recyclable grid energy storage systems.

A novel heuristic technique implemented with FOPI controller for dynamic power management in hybrid energy storage systems

Abstract This paper introduces a power management strategy (PMS) for photovoltaic (PV) and hybrid electrical energy storage (HEES) systems, combining batteries and supercapacitors (SCs). The proposed strategy employs a fractional-order proportional-integral (FOPI) controller, optimised using a novel African Vultures Optimization Algorithm (AVOA), Hybrid Particle Swarm Optimization-Grey Wolf Optimizer (HPSO-GWO), and Grey Wolf Optimizer (GWO). The controller optimised with the new AVOA and HPSO-GWO features shows more effective and improved robustness than conventional algorithms. These findings demonstrate the performance of the PMS and the advantages of AVOA and HPSO-GWO-based tuning strategies for HEES system control. The system’s robustness and efficiency were validated through simulations under various solar irradiance, resistive load conditions, fixed temperature, and pulsed loads in real-time, demonstrating improved transient response and extended battery life. The optimised PMS effectively balances energy distribution, reduces battery stress, and enhances system stability, proving superior to traditional methods in dynamic and complex environments. Furthermore, the effectiveness of the suggested strategy is demonstrated by the decrease in settling time, even with fluctuations in resistive load, fixed temperature, pulsed load, and irradiation.

Experimental Operation of a Prototype 750C Advanced Chloride Molten Salt Bellows Valve

To achieve DOE 2030 SunShot targets that reduce the cost of liquid-based solar by an additional 40% to 70% beyond 2018 costs, a more reliable, highly manufacturable flow valve, capable of achieving operational temperatures of >700°C is required [1]. This paper investigates the development of an innovative high-temperature chloride molten salt valve, with operation up to 750°C. This valve is intended to be employed within Gen 3 CSP liquid-based thermal energy storage (TES) systems as well as Gen 4 modular salt reactor (MSR) technologies. This work details the general design and flow testing of a bellows-seal flow control valve (FCV). This design includes an integrated closed-loop thermal control system to ensure robust design for freeze-thaw cycles. The self-contained thermal management STM system, is unique in the salt valve industry since it is an integrated solution to provide a consistent, repeatable alternative to typical heat tracing. Additionally, the design includes the employment of a novel heat pipe valve stem to facilitate enhanced passive thermal management into the valve assembly. This valve stem heat pipe is designed to facilitate natural circulation within the bonnet to ensure robust operation, during both nominal and transient thermal operation. The valve body and trim will be designed using SS316H, consistent with Flowserve Corporation’s existing product base and is code qualified but will utilize clad material for materials corrosion, manufacturing cost reduction and compatibility to ensure design flexibility. A test campaign was performed in this investigation utilizing a novel 750°C ternary chloride (20%NaCl/40%MgCl2/40%KCl by mol. wt. %) molten salt flow loop. A discussion about the design and installation of the valves within this test bed is provided for this investigation. Valve test results from this study assessed Cv curves as well as multiple actuator cycles, under varying thermodynamic and operational mode conditions, which would be characteristic within a commercial molten salt facility. The results indicate nominal operation for the baseline design, though improved performance and reliability is expected with the full designed FCV.

Giant energy storage density with ultrahigh efficiency in multilayer ceramic capacitors via interlaminar strain engineering

Dielectric capacitors with high energy storage performance are highly desired for advanced power electronic devices and systems. Even though strenuous efforts have been dedicated to closing the gap of energy storage density between the dielectric capacitors and the electrochemical capacitors/batteries, a single-minded pursuit of high energy density without a near-zero energy loss for ultrahigh energy efficiency as the grantee is in vain. Herein, for the purpose of decoupling the inherent conflicts between high polarization and low electric hysteresis (loss), and achieving high energy storage density and efficiency simultaneously in multilayer ceramic capacitors (MLCCs), we propose an interlaminar strain engineering strategy to modulate the domain structure and manipulate the polarization behavior of the dielectric mediums. With a heterogeneous layered structure consisting of different antiferroelectric ceramics [(Pb0.9Ba0.04La0.04)(Zr0.65Sn0.3Ti0.05)O3/(Pb0.95Ba0.02La0.02)(Zr0.6Sn0.4)O3/(Pb0.92Ca0.06La0.02)(Zr0.6Sn0.4)0.995O3], our MLCC exhibits a giant recoverable energy density of 22.0 J cm−3 with an ultrahigh energy efficiency of 96.1%. Combined with the favorable temperature and frequency stabilities and the high antifatigue property, this work provides a strain engineering paradigm for designing MLCCs for high-power energy storage and conversion systems.

A Long-Life Zinc-Bromine Single-Flow Battery Utilizing Trimethylsulfoxonium Bromide as Complexing Agent.

Aqueous zinc-bromine single-flow batteries (ZBSFBs) are highly promising for distributed energy storage systems due to their safety, low cost, and relatively high energy density. However, the limited operational lifespan of ZBSFBs poses a significant barrier to their large-scale commercial viability. Here, trimethylsulfoxonium bromide (TMSO), a nonquaternary ammonium salt, is introduced as a bromine complexing agent to extend the cycle life of ZBSFBs by reducing the imbalance of active substances. Benefiting from the strong interaction between TMSO and H2O, the hydrogen evolution reaction is notably suppressed compared with the traditional N-ethyl-N-methyl-pyrrolidinium bromide (MEP) complexing agent, resulting in reduced bromine accumulation at the cathode. The resultant solid polybromide-TMSO complex, featuring rapid electrochemical redox reaction of Br2/Br-, further contributes to reduce the residual bromine. Consequently, the ZBSFB with TMSO demonstrates a longer lifespan of 1500 cycles with a higher average energy efficiency (EE) of ≈81.6% than that with MEP (less than 300 cycles with an average EE of ≈80.2%). This research explores a sulfonium complexing agent and provides a feasible strategy to effectively extend the cycle life of ZBSFBs.

Coordinated operation of pumped hydro energy storage with reversible pump turbine and co-located battery energy storage system

Abstract This publication examines the coordinated operation of pumped hydro energy storage and battery energy storage systems to improve profitability. While pumped hydro energy storages offer high storage capacity but have slower response times, battery energy storage systems have lower capacity but faster response times. A hybrid system combining both can thus harness synergies. A mixed-integer linear programming model was developed to depict the coordinated use of both systems in the German market. The proposed approach is also applicable to other regional markets where energy and balancing services are traded in a similar manner. In this model, the pumped hydro energy storage operates in the spot market and provides automatic Frequency Restoration Reserve, while the battery energy storage systems supplies Frequency Containment Reserve. The model takes into account the costs caused by degradation effects in both storage types. The results show a 10.05 % increase in revenue through coordination compared to the independent operation of both storage systems. This added value can be achieved through more efficient use of the power capacity, particularly that of the battery energy storage systems, in coordinated operation.

Towards a More Efficient Design of High Temperature Concentrating Solar Power Plant With Cascaded Thermal Energy Storage

This work proposes a novel concentrating solar power (CSP) plant configuration aiming at a high operation temperature of 1000°C. The thermal energy storage system (TES) would be the focus of this research by modifying it and proposing four configurations to enhance the overall efficiency of high-temperature solar power towers. The objective is to identify the most thermodynamically efficient designs by analyzing the literature on the different components and comparing them to a reference base case of a conventional 100 MWe solar power tower plant (2-tank molten salt TES) operating at 565°C. The proposition consists of a Brayton/Rankine combined cycle with a double cascade TES. In the proposed cascade TES, the primary unit consists of a high-temperature air/ceramic packed-bed thermocline operating at 1000°C, while the secondary unit is a single molten salt tank used as sensible heat. The secondary TES is used as a heat sink during charge, improving efficiency and reducing the size of the air/ceramic-packed bed by extracting the thermocline out of the tank. Excess energy stored in the secondary TES is utilized for preheating during discharge. The methodology incorporates evaluating various combinations of solar block, TES, and power block integration. Combinations are selected from a comprehensive literature review. The study focuses on night-time operations. Further analysis of the cost-benefit of the designs would be required to compare the overall energy production and furthermore the LCOE.

Numerical Investigation of Dual Metal Hydride Bed Based Thermochemical Energy Storage System

Thermochemical energy storage system is known for good thermal stability and high energy storage density. Metal hydride based thermochemical energy storage systems are reported to store thermal energy at higher temperatures. In this analysis, NaMgH2F and Mg2NiH4 are used as high temperature and low-temperature metal hydrides. One kg of NaMgH2F is used as thermal energy storage media, while Mg2NiH4 is used as hydrogen storage media. The analysis includes the study of energy charging and discharging characteristics with heat transfer phenomenon in metal hydride with variation in thermal conductivity of high temperature metal hydride bed. With the increase in thermal conductivity of high temperature metal hydride bed, the heat transfer between heat transfer fluid and metal hydride bed during the energy charging and discharging process has improved. A marginal increase in thermal energy stored and discharged in/from the metal hydride bed system has been observed with an increase in the thermal conductivity of the metal hydride bed. Thermal energy stored in the MH beds for thermal conductivity of 0.5 W/m K, 0.75 W/m K, and 1 W/mK, are 270.88 kJ, 273.39 kJ, and 274.96 kJ, respectively. The energy desorbed from the system for thermal conductivity 0.5 W/mK, 0.75 W/mK, and 1 W/mK are observed as 251.25 kJ, 258.22 kJ, and 260.57 kJ, respectively. The three cases of thermal conductivity have reported an energy storage efficiency of 92.75%, 94.45%, and 94.77%, respectively.

Enhanced Polysulfide Conversion and Shuttle Suppression in Lithium-Sulfur Batteries via Fe-Phytate Modified Sulfur Cathode.

The practical application of lithium-sulfur (Li-S) batteries is severely impeded by poor cycling performance arising from sluggish redox kinetics and the shuttle effect of polysulfides. In this work, novel transition metal phytates are pioneered to functionalize conductive carbon to address these key limitations. Among a series of phytates evaluated, the Fe-Phytate-modified carbon (Fe-PA@CB) demonstrates superior specific capacity and rate performance. The unique molecular-level Fe-PA coating ensures uniform dispersion and increased active site, leveraging optimized adsorption and enhanced catalytic properties. Consequently, the activation energy for polysulfide conversion is significantly reduced, and polarization potential is minimized. The Fe-PA@CB electrode demonstrates significantly improved cycling stability, retaining 61% of the initial capacity after 500 cycles, compared to 40% retention by a conventional carbon-based cathode. This work not only provides a practical solution for enhancing the electrochemical performance of Li-S batteries but also offers valuable insights into material design and mechanistic understanding, paving the way for the development of next-generation energy storage systems.

Understanding Redox Organic Behavior in Deep Eutectic Solvents: Considerations for Molecular Design

Abstract Electrolytes based on deep eutectic solvents (DESs) coupled with redox active organic molecules have shown potential as a versatile and energy dense electrochemical energy storage system. However, progress in these systems has been held back by a lack of understanding of the irregular behavior displayed when redox active organic molecules are transitioned from other solvent systems. In this work, the hydrogen bonding characteristics of a series of redox organic molecules were investigated through infrared spectroscopy and molecular modeling. New understanding of these interactions was then used to explain their electrochemical behavior in a DES electrolyte. A model was used to predict the behavior of new derivatives towards the design of an optimized redox organic-DES system. Hydrogen bonding between the redox molecules and the solvent was found to significantly shift the potential of a redox reaction more positive when a hydrogen bond forms at the redox active site. It was predicted that functionalizing a molecule with electron withdrawing groups to lower the electron density of the redox active functional group lowers the strength of the hydrogen bond and thus alleviates the undesirable potential shift. This hypothesis was demonstrated by the addition of nitro groups to fluorenones.

Enhancing Energy Efficiency in Mediterranean Large-Scale Buildings: A Study on Mobilized Thermal-Energy-Storage Systems

This study investigates the use of Mobilized Thermal Energy Storage (MTES) systems to enhance energy efficiency in large-scale Mediterranean buildings, focusing on a university campus in Tripoli, Lebanon. The research question addresses whether MTES can effectively utilize waste heat from a power plant to meet heating, cooling, and water heating needs. We hypothesize that MTES, using Erythritol as the phase change material (PCM) and Therminol55 as the heat transfer fluid (HTF), will improve energy efficiency and reduce costs compared to conventional systems. The methodology involves simulating the MTES system’s performance, including charge, self-discharge, and discharge phases, using Simulink-MATLAB. Key findings reveal that increasing the HTF flow reduces the charging time by 29% and enhances the efficiency by 8%, while larger project scales decrease heat costs. Economic analysis shows a payback period (PBP) of 2 years 11 months for heating only and 2 years 1 month for heating and cooling, with annual maintenance costs considered at 5%. These results demonstrate MTES as a sustainable and cost-effective solution for thermal energy storage, with potential applications in the energy sector.

Decentralized dynamic safety control for battery energy storage system in autonomous DC microgrids

This paper is aiming to address a decentralized dynamic safety control issue for battery energy storage system in DC microgrids. A novel dynamic control barrier function (DCBF) based on nonlinear disturbance observers is devised in the decentralized converter control to restrain the current value while ensuring DC bus voltage regulation. First, a DCBF dependent on load variation is built in order to restrain the current value of each energy storage unit triggered by sudden load changes. Second, a decentralized composite control law, incorporating the DCBF via quadratic program (QP), achieves the objective of current constraint while ensuring the large-signal stability of the DC microgrids. The efficacy of the proposed method has been validated through both simulations and experimental comparison tests.

Ultrahigh Energy Storage Capability in Polyetherimide‐Based Polymer Dielectrics Through Trapping Free Radicals Strategy

AbstractPolymer film capacitors are widely utilized in electronics and power suppliers because of high power density and fast charge–discharge speed. Flexible polymer that tolerates the extremes of working temperature and electric field is essential for advanced energy storage systems. Here, hyperbranched polyethylene copolymer inoculated with N–hydroxyethyl maleimide (HBPE@HEPD) has been synthesized to modify boron nitride nanosheets (HEPD‐BNNSs) via non‐covalent interaction during liquid‐phase exfoliation. The conjugated double bond serves as trapping effect through the addition reaction with free radicals in HEPD‐BNNSs/polyetherimide (PEI) nanocomposite that delays the formation of electrical treeing at initial stage of breakdown. The resultant HEPD‐BNNSs/PEI film illustrates a superior energy storage capability, e.g. discharged energy density of 12.9 J cm−3 and efficiency >90% at 500 MV m−1 and room temperature are obtained in 0.5 wt.% nanocomposite, and discharged energy density of 5.8 J cm−3 under 100 °C with efficiency of 90.2% at 350 MV m−1 is achieved in current film. The prepared HEPD‐BNNSs/PEI nanocomposite also has eminent fatigue resistance at 200 MV m−1 with charge–discharge operation over 105 cycles. This strategy of trapping free radicals at initial stage of breakdown reveals a fresh prospect of polymer dielectrics for film capacitor.

Equivalent system frequency response model with energy storage

Providing Frequency Response (FR) using energy storage system (ESS) has been adopted in power systems worldwide to reduce the maximum frequency deviation. This paper presents a new equivalent system frequency response model with ESS. The model can be conveniently used to assess the system frequency nadir and calculate the capacity and equivalent droop of storage considering the maximum frequency deviation in a synchronous generator (SG) dominated system. Unlike existing calculation methods based on control strategies such as fuzzy-logic, robust control, data-driving control and predictive algorithm, the proposed method (i) uses the equivalent capacity and equivalent droop to describe the FR of SG and ESS, thereby avoids the difficulty in solving high-order FR model and (ii) does not need the control strategy of SGs in the network. Therefore, the proposed method provides a simple yet systematic method in calculating the capacity and equivalent droop of ESS. The effectiveness of the proposed method is demonstrated using the four-generator two-area (4G2A) system with 0 %, 25 % and 50 % penetration of renewable resources and different types of SGs (hydraulic and steam SG) based on the given maximum frequency deviation..

Energy, Exergy, Economic and Exergoeconomic (4E) Analysis of a High-Temperature Liquid CO2 Energy Storage System: Dual-Stage Thermal Energy Storage for Performance Enhancement

Liquid carbon dioxide energy storage (LCES) system can improve the renewable energy penetration in the grid, but the mismatch between the compression heat and thermal energy storage (TES) system causes considerable irreversible losses. In this paper, a novel high-temperature (300∼400°C) LCES system with a dual-stage TES loop is introduced to enhance the heat transfer and energy storage performance. The proposed high-temperature LCES system is analyzed from the perspectives of energy, exergy, economics and exergoeconomics. Under design conditions, the round-trip efficiency, energy storage density, and levelized cost of electricity of the improved LCES system are 66.68%, 28.57kWh·m-3, and 0.1315$·kWh-1, respectively. The dual-stage TES loop improves the heat recovery factor and round-trip efficiency by 19.10% and 14.59% compared to the basic LCES system. The parametric analysis indicates that the system performance initially improves and then declines as the operating temperature of the low-temperature TES loop increases. The multi-objective optimization results show that the round-trip efficiency and energy storage density of the proposed high-temperature LCES system are at least 7.43% and 62.49% higher than those of low-temperature LCES systems.

Revealing the contribution of flame spread to vertical thermal runaway propagation for energy storage systems

The rapidly growing energy storage systems necessitate more high-capacity lithium iron phosphate batteries but pose significant safety concerns. In multi-layer battery clusters, if thermal runaway propagation occurs between modules, particularly in the vertical direction, the ensuing fire spread can further result in the accelerated propagation of battery and even an irrevocable catastrophe. Clarifying the contribution of flame spread to vertical thermal runaway propagation is the goal of this investigation. The unexpected propagation characteristics between the upper and lower modules are explored. Further, the critical heat and the percentage of heat that leads to thermal runaway in the upper battery are determined using the equivalent replacement battery. The flame heat transfer is finally decoupled using the thermal radiation model. And the mechanism of vertical thermal runaway propagation induced flame between modules is analyzed. The findings reveal that the higher module's thermal runaway and venting sequence differs from the lower module's, suggesting that flame spread dominated the thermal runaway propagation paths. The critical triggering energy of the upper battery is 1193.6 kJ, comprising 279 kJ of conductive heat, 750 kJ of flame heat, and 164.6 kJ of self-generation heat, with the flame heat accounting for approximately 1.18 % of the total heat released from the battery fire. In contrast to horizontal thermal runaway propagation, where thermal conduction is predominant, the convection heat from battery fire serves as the main heat source for vertical propagation. The findings serve as a foundation for both emergency response to fire incidents and the safe design of battery modules in existing energy storage systems.

Enhancing energy hub management with unified plug-in electric vehicle based demand response and energy storage systems

Enhancing energy hub management with unified plug-in electric vehicle based demand response and energy storage systems

Energy management of a microgrid with integration of renewable energy sources considering energy storage systems with electricity price

Energy management of a microgrid with integration of renewable energy sources considering energy storage systems with electricity price