Energy Storage and Applications doi: 10.3390/esa3020007

Authors: Roy van Zijl Jonas Dalitz Prasanth Venugopal

The development of battery-powered electric aircraft for use in commercial aviation involves various performance- and safety-based challenges. Cells with high energy densities (for instance Li-Ion pouches) are required to meet the performance requirements, with those currently available encompassing a risk of thermal runaway and other failures. To enable their use, this work provides an investigation into battery abuse conditions and their effect on the overall safety of the system, tailored to electric aviation. A system architecture is presented for a battery-powered electric aircraft, including recommended mitigation methods for the presented failure modes. A framework for determining the overall State of Safety based on the relevant abuse conditions is presented. It is found that the influence of atmospheric operation conditions, flight profiles and vibrations provide the most notable differences between battery-associated risks for aircraft and ground vehicle purposes. Quantification and experimental validation of the impact of these conditions is recommended as a direction for future work.

Energy Storage and Applications doi: 10.3390/esa3010006

Authors: Gianluca Pozzi Giulia Vignati

The global shift toward renewable energy systems raises major challenges related to the variability of solar and wind power and their poor alignment with electricity demand. This paper addresses energy adequacy, defined as the ability of an energy system to reliably meet demand by balancing generation, storage, transmission, and reserves for unforeseen events. Within this framework, energy storage systems are identified as strategic components, requiring a diversified and multi-scale set of solutions-from territorial to building scale-to respond to infrastructural constraints and user behaviour. The study adopts a multi-scalar and interdisciplinary methodology combining deductive and inductive approaches. The deductive analysis examines global, European, and Italian electricity systems, highlighting issues such as overcapacity and grid instability caused by the uncoordinated development of renewable generation and network infrastructures. The inductive approach focuses on existing storage technologies, with particular attention to two types of thermal energy storage selected for their simplicity, scalability, and replicability. Hydropower reservoirs are also considered due to their multifunctional role in energy balancing. Two case studies developed by the research group—a public building energy retrofit in Milan and a modular off-grid housing prototype—demonstrate how integrated storage solutions can enhance system flexibility. The results emphasize the necessity of a systemic design approach that combines storage technologies, adaptable energy use, and active user participation to ensure energy adequacy in scenarios with high renewable penetration.

Energy Storage and Applications doi: 10.3390/esa3010005

Authors: Abderrahmane Waqdim Mohamed Agouri Hakima Ouhenou Lhouceine Moulaoui Abderrahman Abbassi Souad Taj Bouzid Manaut Moha El Idrissi Omar Bajjou Khalid Rahmani

The search for effective hydrogen storage materials has stimulated extensive research into compounds with high storage capacity and stability. In this study, we explored lithium-based hydride perovskites, LiXH3(X=Ge,Ru), as potential candidates for solid-state hydrogen storage applications. Our results reveal that both compounds possess remarkable structural stability, which is confirmed by phonon dispersion analysis, negative formation energies, elementary molecular dynamics simulations (AIMD), and elastic static evaluations. The calculated optoelectronic properties indicate the metallic character of both perovskites. Moreover, the thermodynamic behavior was examined under various temperature and pressure conditions. Importantly, the predicted hydrogen storage characteristics—including gravimetric and volumetric capacities as well as hydrogen desorption temperatures—meet the U.S. Department of Energy (DOE) targets. These findings suggest that LiXH3(X=Ge,Ru) perovskites are promising materials for sustainable solid-state hydrogen storage, contributing to the advancement of clean and efficient energy technologies.

Energy Storage and Applications doi: 10.3390/esa3010004

Authors: Andrew J. Hutchinson Chris M. Harrison Thomas S. Bryden Arman Alahyari Yiheng Hu Daniel T. Gladwin Jonathan Radcliffe Daniel J. Rogers Charalampos Patsios Andrew Forsyth

Demand for new solutions to emerging issues faced by the electricity generation, demand and supply industries continues to increase with the introduction of increasing proportions of variable renewable energy and changing system demands. Energy storage systems represent a key part of the solution as stakeholders attempt to move towards a ‘net zero’ system. Within research, studies into the techno-economic optimisation of varied energy storage technologies for different applications continue to play a significant role in this changing landscape. A key aspect of this research is the modelling and simulation of such systems, often with the goal of optimising their parameters for deploying in specific roles and services. This paper presents an extensive analysis of the current economic outlook for five major energy storage technologies, highlighting the significant variation in quoted costs within the literature. It presents a unique and novel perspective by considering economic and optimisation modelling from both a technology and application-centric approach. It explores the different approaches available for performing economic analysis on energy storage systems, providing a novel overview of the advantages of various approaches along with examples from the literature on how these studies are implemented. Finally, the paper explores optimisation studies, giving an in-depth explanation of different approaches used in the optimisation of energy storage systems and reviewing prominent uses within the literature. The paper concludes with a consideration of the main challenges that face the field of techno-economic energy storage studies and provides recommendations on areas that require further research.

Energy Storage and Applications doi: 10.3390/esa3010003

Authors: Anti Kur Jo Darkwa John Calautit Rabah Boukhanouf

Pure calcium hydroxide, Ca(OH)2, and magnesium hydroxide, Mg(OH)2, are limited in their applicability for the storage of medium-temperature heat due to their high dehydration temperatures. Modification of the hydroxides by doping with appropriate materials is a viable method for solving this problem. In this work, samples of Ca(OH)2 and Mg(OH)2 have been doped with various proportions of boron nitride (BN) and potassium nitrate (KNO3) to reduce their dehydration temperatures. The results showed that the doping processes were successfully achieved as desired, but there was a reduction in their surface areas and porosity, which could impact their thermodynamic behavior. However, the thermal analysis on the samples revealed that the KNO3 had a more positive effect on the Mg(OH)2 material than Ca(OH)2. For instance, a reduction of 23 °C in the dehydration temperature and an increase of 6% in heat storage capacity were achieved with 5 wt% KNO3-doped Mg(OH)2, thus making it applicable for heat storage in the temperature range of 293–400 °C. Thermodynamic and kinetic studies on this composite material are therefore encouraged to establish its full potential.

Energy Storage and Applications doi: 10.3390/esa3010002

Authors: Seth A. Thomas Vamsi Krishna Kukkapalli Sunwoo Kim

Hydrogen storage is vital to the development of renewables, especially in low-infrastructure countries. Metal hydrides offer a small but safe solid-state candidate for hydrogen storage at medium pressures and near-ambient temperature, yet large-scale applications face heat-management challenges. In this article, we numerically analyze examples of two large-scale lanthanum pentanickel (LaNi5)-based metal hydride reactor configurations with shell-and-tube heat exchangers. This research studies two large-scale shell-and-tube metal hydride reactor configurations: a tube-side cooling reactor with hydride powder packed in the shell and coolant flowing through internal tubes, and a shell-side cooling reactor using annular hydride pellets with coolant circulating through the shell. The thermal and kinetic performance of these large-scale reactors was simulated using COMSOL Multiphysics (version 6.1) and analyzed under different geometries and operating conditions typical of industrial scales. The tube-side solution provided 90% hydrogen absorption in 1500–2000 s at 30 bar, while the shell-side solution reached the same level of absorption in 430 s at 10 bar. Results show that tube-side cooling has higher storage, while shell-side cooling improves heat removal and kinetics. For energy and maritime transport applications, these findings reveal optimization insights for large-scale, efficient hydrogen storage systems.

Energy Storage and Applications doi: 10.3390/esa3010001

Authors: Niclas Hampel André Xhonneux Dirk Müller

The waste heat generated by high-performance computing (HPC) represents an opportunity for advancing the decarbonization of energy systems. Seasonal storage is necessary to regulate the balance between waste heat production and demand. High-temperature aquifer thermal energy storage (HT-ATES) is a particularly well-suited technology for this purpose due to its large storage capacity. However, integrating HT-ATES into energy systems for district heating is complex, affecting existing components. Therefore, this study applies a bi-objective mixed-integer quadratically constrained programming (MIQCP) approach to optimize the energy system at Forschungszentrum Jülich (FZJ) regarding total annualized costs (TAC) and global warming impact (GWI). The exascale computer Jupiter, which is hosted at FZJ, generates a substantial amount of renewable waste heat that is suitable for integration into district heating networks and seasonal storage. Case studies show that HT-ATES integration into the investigated system can reduce GWI by 20% and increase TAC by 1% compared to the reference case. Despite increased TAC from investments and heat pump (HP) operation, summer charging of the HT-ATES remains flexible and cost-effective. An idealized future scenario indicates that HT-ATES with a storage capacity of 16,990 MWh and HPs could cover most of the heating demand, reducing GWI by up to 91% while TAC increases by 6% relative to the reference system.

Energy Storage and Applications doi: 10.3390/esa2040018

Authors: Yitong Wu Chairunnisa Kyaw Thu Takahiko Miyazaki

Current CO2-based energy storage systems still face several unsolved technical challenges, including strong thermal destruction between the multi-stage compression and expansion processes, significant exergy destruction in heat exchange units, limited utilization of low-grade heat, and the lack of an integrated comprehensive performance framework capable of simultaneously evaluating thermodynamic, economic, and environmental performance. Although previous studies have explored various compressed CO2 energy storage (CCES) configurations and CCES–Organic Rankine Cycle (ORC) couplings, most works treat the two subsystems separately, neglect interactions between the heat exchange loops, or overlook the combined effects of exergy losses, cost trade-offs, and CO2-emission reduction. These gaps hinder the identification of optimal operating conditions and limit the system-level understanding needed for practical application. To address these challenges, this study proposes an innovative system that integrates a multi-stage CCES system with ORC. The system introduces ethylene glycol as a dual thermal carrier, coupling waste-heat recovery in the CCES with low-temperature energy utilization in the ORC, while liquefied natural gas (LNG) provides cold energy to improve cycle efficiency. A comprehensive 4E (energy, exergy, economic, and environmental) assessment framework is developed, incorporating thermodynamic modeling, exergy destruction analysis, CEPCI-based cost estimation, and environmental metrics including primary energy saved (PES) and CO2 emission reduction. Sensitivity analyses on the high-pressure tank (HPT) pressure, heat exchanger pinch temperature difference, and pre-expansion pressure of propane (P30) reveal strong nonlinear effects on system performance. A multi-objective optimization combining NSGA-II and TOPSIS identifies the optimal operating condition, achieving 69.6% system exergy efficiency, a 2.07-year payback period, and 1087.3 kWh of primary energy savings. The ORC subsystem attains 49.02% thermal and 62.27% exergy efficiency, demonstrating synergistic effect between the CCES and ORC. The results highlight the proposed CCES–ORC system as a technically and economically feasible approach for high-efficiency, low-carbon energy storage and conversion.

Energy Storage and Applications doi: 10.3390/esa2040017

Authors: Alon Davidy

Molten salt heat exchangers are crucial components in systems requiring high-temperature heat transfer and energy storage, especially in renewable energy and advanced nuclear technologies. Their ability to operate efficiently at high temperatures while offering significant energy storage capacity makes them highly valuable in modern energy systems. They have high thermal stability. In the framework of this research, a computational fluid dynamics (CFD) simulation model of the HITEC molten salt cooling system has been developed. HITEC molten salt is a specialized heat transfer and thermal energy storage medium primarily used in industrial processes and solar thermal power plants. It is a eutectic blend of sodium nitrate, sodium nitrite, and potassium nitrate. COMSOL multi-physics code has been employed in this research. It simultaneously solves the fluid flow, energy, and heat conduction transport equations. Two cases have been investigated in this paper: a water flowing velocity of 1 [m/s] and a water flowing velocity of 10 [m/s]. The results indicate that the maximal surface temperature of the Crofer®22 H reached 441.2 °C in the first case. The maximal surface temperature of the Crofer®22 H reached 500 °C in the second case. Crofer®22 H alloy provides excellent steam oxidation, high corrosion resistance, and thermal creep resistance. The proposed HITEC molten thermal system may be applied in the oil and gas industries and in power plants (such as the Organic Rankine Cycle).

Energy Storage and Applications doi: 10.3390/esa2040016

Authors: Francis P. Moissinac Yiannis Georgantas Yang Sha Mark A. Bissett

The global decarbonisation strategy has accelerated the shift toward renewable energy and electric transport, demanding advanced electrochemical energy storage systems. Conventional anodes such as graphite and silicon composites face challenges in conductivity, stability and cycling performance. MXenes, a class of two-dimensional (2D) materials, offer promising alternatives owing to their metallic conductivity, tunable surface chemistry and high theoretical capacity. Here, we synthesise and characterise Mo2TiC2Tx and V2CTx (T = O, OH, F and/or Cl) MXenes for lithium-ion battery anodes and supercapacitors. Unlike Ti3C2Tx, which stores charge via intercalation and surface redox reactions, Mo2TiC2Tx and V2CTx exhibit conversion-type mechanisms. We also identify novel V2C–VOx heterostructures, achieving a specific capacitance of 532.4 F g−1 at 2 mV s−1 and an initial capacity of 493.3 mAh g−1 at 50 mA g−1 in lithium half-cells, with a low decay rate of 0.071% per cycle over 200 cycles. Pristine Mo2TiC2Tx shows 391.7 mAh g−1 at 50 mA g−1, decaying by 0.109% per cycle. These results experimentally validate theoretical predictions, revealing how MXene structure and transition metal chemistry govern electrochemical behaviour, thus guiding electrode design for next-generation batteries and supercapacitors.

Energy Storage and Applications doi: 10.3390/esa2040015

Authors: Denis Okello Jimmy Chaciga Ole Jorgen Nydal Karidewa Nyeinga

The paper examines the experimental performance of air–rock bed, oil only, and oil–rock bed systems for storing heat suitable for cooking applications. The air–rock bed system is charged using hot air from a compressed air tank, while the oil–rock bed system employs a resistive heating element to heat a small volume of oil, which then circulates naturally. The charging process for the oil systems was controlled by adjusting funnel heights, and temperature measurements were taken using thermocouples connected to a data logger. Both systems can store thermal energy ranging from 4.5 kWh to 8 kWh and achieve temperatures between 150 °C and 300 °C, depending on supply temperatures. The simpler oil–rock bed allows for the direct boiling of water using the high temperature produced, and tests indicated comparable boiling times between systems. The findings suggest that these heat storage systems could enhance the advancement and integration of solar cookers, enabling more flexible cooking options.

Energy Storage and Applications doi: 10.3390/esa2040014

Authors: Elinor Ginzburg-Ganz Itay Segev Yoash Levron Juri Belikov Dmitry Baimel Sarah Keren

The challenge of optimally controlling energy storage systems under uncertainty conditions, whether due to uncertain storage device dynamics or load signal variability, is well established. Recent research works tackle this problem using two primary approaches: optimal control methods, such as stochastic dynamic programming, and data-driven techniques. This work’s objective is to quantify the inherent trade-offs between these methodologies and identify their respective strengths and weaknesses across different scenarios. We evaluate the degradation of performance, measured by increased operational costs, when a reinforcement learning policy is adopted instead of an optimal control policy, such as dynamic programming, Pontryagin’s minimum principle, or the Shortest-Path method. Our study examines three increasingly intricate use cases: ideal storage units, storage units with losses, and lossy storage units integrated with transmission line losses. For each scenario, we compare the performance of a representative optimal control technique against a reinforcement learning approach, seeking to establish broader comparative insights.

Energy Storage and Applications doi: 10.3390/esa2030013

Authors: Jacek A. Biskupski

This article analyses the possibility of using Li-ion batteries removed from battery electric vehicles (BEVs) as short-term energy storage devices in a near-zero energy building (nZEB) in conjunction with a rooftop photovoltaic (PV) system. The technical and economic feasibility of this solution was compared to that of a standard commercial LIB (Lithium-Ion battery) BESS Battery Energy Storage System). Two generations of the same BEV model battery were tested to analyse their suitability for powering a building. The necessary changes to the setup of such a battery for building power supply purposes were analysed, as well as its suitability. As a result, analyses of profitability over the predicted life span and NPV (net present value) of SLEVBs (second-life BEV batteries) for building power were carried out. The study also conducted preliminary research on the effectiveness of such projects and their pros and cons in terms of security. The author calculates the profitability of a ready-made PV BESS with a set of SLEVBs, estimating the payback periods for such investments relative to electricity prices in Poland. The article concludes on the potential of SLEVBs to support self-consumption in nZEB buildings and its environmental impact on the European circular economy.

Energy Storage and Applications doi: 10.3390/esa2030012

Authors: José Miguel Mahía-Prados Ignacio Arias-Fernández Manuel Romero Gómez

Methane, transported as Liquefied Natural Gas (LNG) at −163 °C, is becoming the leading fuel in the decarbonization of the maritime sector within the low-carbon fuels. More than 30 years of knowledge has allowed the development of an extensive offshore supply network that includes regasification plants to store and supply it to the grid, both onshore and offshore. This article first reviews the current state of the sector. Then, the operation of a typical onshore regasification plant and the heat transfer through the storage tanks that causes the generation of boil-off gas (BOG) are analyzed by means of two different methodologies. Finally, and based on the results obtained, the different improvements that can be implemented in this type of installation to improve its energy efficiency and insulation are established, such as, for example, an improvement of more than 4 W/m2 by reinforcing the thickness of the materials of the tank dome.

Energy Storage and Applications doi: 10.3390/esa2030011

Authors: Ammar Ali Sohel Anwar Afshin Izadian

This paper presents a comparative study of data-driven modeling approaches for vanadium redox flow batteries (VRFBs), utilizing Multiple Linear Regression (MLR) and Random Forest (RF) algorithms. Experimental voltage–capacity datasets from a 1 kW/1 kWh VRFB system were digitized, processed, and used for model training, validation, and testing. The MLR model, built using eight optimized features, achieved a mean error (ME) of 0.0204 V, a residual sum of squares (RSS) of 8.87, and a root mean squared error (RMSE) of 0.1796 V on the test data, demonstrating high predictive performance in stationary operating regions. However, it exhibited limited accuracy during dynamic transitions. Optimized through out-of-bag (OOB) error minimization, the Random Forest model achieved a training RMSE of 0.093 V and a test RMSE of 0.110 V, significantly outperforming MLR in capturing dynamic behavior while maintaining comparable performance in steady-state regions. The accuracy remained high even at lower current densities. Feature importance analysis and partial dependence plots (PDPs) confirmed the dominance of current-related features and SOC dynamics in influencing VRFB terminal voltage. Overall, the Random Forest model offers superior accuracy and robustness, making it highly suitable for real-time VRFB system monitoring, control, and digital twin integration. This study highlights the potential of combining machine learning algorithms with electrochemical domain knowledge to enhance battery system modeling for future energy storage applications.

Energy Storage and Applications doi: 10.3390/esa2030010

Authors: Julius Abayateye Daniel J. Zimmerle

This study analyzed the frequency control challenges within the West Africa Power Pool Interconnected Transmission System (WAPPITS) as it plans to incorporate variable renewable energy (VRE) resources, such as wind and solar energy. Concerns center on the ability of WAPPITS primary frequency control reserves to adapt to high VRE penetration given the synchronization and frequency control problems experienced by the three separate synchronous blocks of WAPPITS. Optimizing solutions requires a better understanding of WAPPITS’ current frequency control approach. This study used questionnaires to understand operators’ practical experience with frequency control and compared these observations to field tests at power plants and frequency response metrics during system events. Eight (8) of ten (10) Transmission System Operators (TSOs) indicated that primary frequency control service was implemented in the TSO, but nine (9) of ten TSOs indicated that the reserves provided were inadequate to meet system needs. Five (5) of ten (10) respondents answered “yes” to the provision of secondary frequency control service, while only one (1) indicated that secondary reserves were adequate. Three (3) TSOs indicated they have AGC (Automatic Generation Control) installed in the control room, but none have implemented it for secondary frequency control. The results indicate a significant deficiency in primary control reserves, resulting in a reliance on under-frequency load shedding for primary frequency control. Additionally, the absence of an AGC system for secondary frequency regulation required manual intervention to restore frequency after events. To ensure the effectiveness of battery energy storage systems (BESSs) and the reliable operation of the WAPPITS with a higher penetration of inverter-based VRE, this paper recommends (a) implementing and enforcing basic primary frequency control structures through regional regulation and (b) establishing an ancillary services market to mobilize secondary frequency control resources.

Energy Storage and Applications doi: 10.3390/esa2030009

Authors: Allan John Butler Akhtar Kalam

Green hydrogen, produced through renewable-powered electrolysis, has the potential to revolutionize energy systems; however, its widespread adoption hinges on achieving competitive production costs. A critical challenge lies in optimising the hydrogen production process to address solar and wind energy’s high variability and intermittency. This paper explores the role of artificial intelligence (AI) in reducing and streamlining hydrogen production costs by enabling advanced process optimisation, focusing on electricity cost management and system-wide efficiency improvements.

Energy Storage and Applications doi: 10.3390/esa2030008

Authors: Chung-Han Yang Jack Huang

This review explores the development of energy storage technologies and governance frameworks in the Asia-Pacific region, where rapid economic growth and urbanisation drive the demand for sustainable energy solutions. Energy storage systems (ESS) are integral to balancing renewable energy fluctuations, improving grid resilience, and reducing greenhouse gas emissions. This paper examines the role of international organisations, including the United Nations, International Energy Agency (IEA), and International Renewable Energy Agency (IRENA), in promoting energy storage advancements through strategic initiatives, policy frameworks, and funding mechanisms. Regionally, the Asia-Pacific Economic Cooperation (APEC), the Association of Southeast Asian Nations (ASEAN), and the Asian Development Bank (ADB) have launched programs fostering collaboration, technical support, and knowledge sharing. Detailed case studies of Japan, Thailand, and China highlight the diverse policy approaches, technological innovations, and international collaborations shaping energy storage advancements. While Japan emphasises cutting-edge innovation, Thailand focuses on regional integration, and China leads in large-scale deployment and manufacturing. This analysis identifies key lessons from these frameworks and case studies, providing insights into governance strategies, policy implications, and the challenges of scaling energy storage technologies. It offers a roadmap for advancing regional and global efforts toward achieving low-carbon, resilient energy systems aligned with sustainability and climate goals.

Energy Storage and Applications doi: 10.3390/esa2020007

Authors: Adel Razek

Electric vehicles are increasingly being used for green transportation in smart urban mobility, thus protecting environmental biodiversity and the ecosystem. Energy storage by electric vehicle batteries is a critical point of this ecologically responsible transportation. This storage is strongly linked to the different external managements related to its capacity state. The latter concerns the interconnection of storage to energy resources, charging strategies, and their complexity. In an ideal urban context, charging strategies would use wireless devices. However, these may involve complex frames and unwanted electromagnetic field interferences. The sustainable management of wireless devices and battery state conditions allows for optimized operation and minimized adverse effects. Such management includes the sustainable design of devices and monitoring of complex connected procedures. The present study aims to analyze this management and to highlight the mathematical routines enabling the design and control tasks involved. The investigations involved are closely related to responsible attitude, “One Health”, and twin supervision approaches. The different sections of the article examine the following: electric vehicle in smart mobility, sustainable design and control, electromagnetic exposures, governance of physical and mathematical representation, charging routines, protection against adverse effects, and supervision of complex connected vehicles. The research presented in this article is supported by examples from the literature.

Energy Storage and Applications doi: 10.3390/esa2020006

Authors: Lijun Fu Qunting Qu Lili Liu Rudolf Holze

Composite electrolytes for applications in electrochemical energy technology, i.e. in batteries and supercapacitors, are gaining increasing attention. In the absence of a commonly accepted definition a ternary combination of materials, e.g. a polymer with an electrolyte salt or electrolyte salt solution and a third conductivity-enhancing constituent, is assumed as a definition of a composite electrolyte in the following review. Relevant fundamentals and reported research results up to explanations of the observed effects and improvements are reviewed. Future perspectives and directions of further research are indicated.

Energy Storage and Applications doi: 10.3390/esa2020005

Authors: Jonathan G. Love Michelle Gane Anthony P. O’Mullane Ian D. R. Mackinnon

We report on the first stage of an energy systems integration project to develop hybrid renewable energy generation and storage of hydrogen for subsequent use via research-based low regret system testbeds. This study details the design and construction of a flexible plug-and-play hybrid renewable power and hydrogen system testbed with up to 50 kW capacity aimed at addressing and benchmarking the operational parameters of the system as well as key components when commissioned. The system testbed configuration includes three different solar technologies, three different battery technologies, two different electrolyser technologies, hydrogen storage, and a fuel cell for regenerative renewable power. Design constraints include the current limit of an AC microgrid, regulations for grid-connected inverters, power connection inefficiencies, and regulated hazardous area approval. We identify and show the resolution of systems integration challenges encountered during construction that may benefit planning for the emerging pilot, or testbed, configurations at other sites. These testbed systems offer the opportunity for informed decisions on economic viability for commercial-scale industry applications.

Energy Storage and Applications doi: 10.3390/esa2020004

Authors: Zac Cesaro Rasmus Bramstoft René Bañares-Alcántara Matthew C. Ives

Green hydrogen and ammonia are forecast to play key roles in the deep decarbonization of the global economy. Here we explore the potential of using green hydrogen and ammonia to couple the energy, agriculture, and industrial sectors with India’s national-scale electricity grid. India is an ideal test case as it currently has one of the most ambitious hydrogen programs in the world, with projected electricity demands for hydrogen and ammonia production accounting for over 1500 TWh/yr or nearly 25% of India’s total electricity demand by 2050. We model the ambitious deep decarbonization of India’s electricity grid and half of its steel and fertilizer industries by 2050. We uncover modest risks for India from such a strategy, with many benefits and opportunities. Our analysis suggests that a renewables-based energy system coupled with ammonia off-take sectors has the potential to dramatically reduce India’s greenhouse emissions, reduce requirements for expensive long-duration energy storage or firm generating capacity, reduce the curtailment of renewable energy, provide valuable short-duration and long-duration load-shifting and system resilience to inter-annual weather variations, and replace tens of billions of USD in ammonia and fuel imports each year. All this while potentially powering new multi-billion USD green steel and maritime fuel export industries. The key risk for India in relation to such a strategy lies in the potential for higher costs and reduced benefits if the rest of the world does not match their ambitious investment in renewables, electrolyzers, and clean storage technologies. We show that such a pessimistic outcome could result in the costs of green hydrogen and ammonia staying high for India through 2050, although still within the range of their gray counterparts. If on the other hand, renewable and storage costs continue to decline further with continued global deployment, all the above benefits could be achieved with a reduced levelized cost of hydrogen and ammonia (10–25%), potentially with a modest reduction in total energy system costs (5%). Such an outcome would have profound global implications given India’s central role in the future global energy economy, establishing India’s global leadership in green shipping fuel, agriculture, and steel, while creating an affordable, sustainable, and secure domestic energy supply.

Energy Storage and Applications doi: 10.3390/esa2010003

Authors: Nirashi Polwaththa Gallage Nihal Kularatna Dulsha Kularatna-Abeywardana Alistair Steyn-Ross

More recently, researchers and the industrial community have started researching DC appliances and DC microgrids as a means of increasing the end-to-end efficiency of systems. Given the fluctuating nature of renewable resources, energy storage becomes mandatory in powering households with minimal AC grid supply, and rechargeable battery packs with maximum power point tracking controllers with inverters are used. However, this approach is not the most efficient due to losses in the power converters used in the energy supply path, while short life and environmental concerns of battery storage also come into play. With the rapid development of commercial super-capacitors, with longer life, higher power density and wider operational temperature range, this device family can be at the center of a new development era, for power converters for DC homes and DC appliances. The new family of converters and protection systems known as supercapacitor-assisted techniques is a unique new approach to minimize or eliminate batteries while improving the ETEE. These new SCA techniques are based on a new theoretical concept now published as supercapacitor-assisted loss management theory. In this paper, we will demonstrate how we extend SCALoM theory to develop SCA converters for whiteware, with the example of a DC-converted commercial double-door refrigerator with implementation details.

Energy Storage and Applications doi: 10.3390/esa2010002

Authors: Diogo Martins Tiago Cabrita João Rodrigues Jaime Puna João Gomes

This paper presents a study on the addition of liquefied biomass of different lignocellulosic forest residues as a means to enhance the co-electrolysis process leading to the production of synthesis gas, composed of H2, CO, CO2, and O2, also known as syngas, with the aim of a subsequent conversion into methane and methanol. Tests were made on a 1 kW prototype unit and showed that the use of liquefied biomass clearly enhances the reaction leading to syngas production. The optimisation study performed showed that the best results are obtained with an addition of 2.5% mass of liquefied biomass obtained from Acacia melanoxylon and operating conditions of a pressure of 4 bar gauge and a temperature of 110 °C.

Energy Storage and Applications doi: 10.3390/esa2010001

Authors: Zhaoyang Dong Yuechuan Tao Shuying Lai Tianjin Wang Zhijun Zhang

Battery Energy Storage Systems (BESSs) are critical in modernizing energy systems, addressing key challenges associated with the variability in renewable energy sources, and enhancing grid stability and resilience. This review explores the diverse applications of BESSs across different scales, from micro-scale appliance-level uses to large-scale utility and grid services, highlighting their adaptability and transformative potential. This study also includes advanced applications such as mobile energy storage, second-life battery utilization, and innovative models like Energy Storage as a Service (ESaaS) and energy storage sharing. Additionally, it discusses the integration of machine learning (ML) and large language models (LLMs), including advanced reinforcement learning (RL) algorithms, to optimize BESS operations and ensure safety through dynamic and data-driven decision-making. By examining current technologies, modeling methods, and future trends, this review provides a comprehensive overview of BESSs as a cornerstone technology for sustainable and efficient energy management, leading to a resilient energy future.

Energy Storage and Applications doi: 10.3390/esa1010005

Authors: Elinor Ginzburg-Ganz Juri Belikov Liran Katzir Yoash Levron

Stability studies remain a crucial aspect of power systems dynamic analysis, and are typically explored in three main categories: numerical methods, linearization techniques, or direct methods, which utilize Lyapunov energy functions. This paper belongs to the third category, and highlights the usefulness of the Popov stability criterion in the analysis of nonlinear power system models. The main advantage of this criterion is that it provides conditions for global asymptotic stability of an equilibrium point, for a nonlinear dynamic system. We show a general method to apply this stability criterion, and examine its uses in several specific applications and case-studies. The results are demonstrated by analyzing the stability of a system that includes a grid-connected storage device and a renewable energy source.

Energy Storage and Applications doi: 10.3390/esa1010004

Authors: Luca Tendera Gerrit Karl Mertin Carlos Gonzalez Dominik Wycisk Alexander Fill Kai Peter Birke

The precise determination of the specific heat capacity of lithium-ion cells is essential for thermal management design. Though, varying influences and insufficient parametric analyses are found in the literature. Therefore, a simple and inexpensive measurement setup is utilized to measure the specific heat capacity of cells independent of their format and dimensions. A comprehensive parametric analysis is performed assessing the effect of cell casing, cell chemistry, temperature, state-of-charge, and state-of-health. For the first time ever, a predictive analysis on material level is conducted allowing for understanding the individual factors in detail. Thus, an analytical approach for calculating the specific heat capacity can be validated by comparing predictive values to experimental data for the first time. It is found that the cell format has a significant influence on the specific heat capacity due to varying mass fractions and housing materials. Furthermore, the cell chemistry and corresponding layer thicknesses are of high importance, too. By selecting specific heat capacities for individual materials from the general literature, the analytical prediction matches the experimental data and is thus validated for the first time ever. Moreover, temperature has a positive linear effect on the specific heat capacity which can increase by up to 15% over the operating range. Furthermore, the positive temperature dependency improves the charging performance. Finally, neither SOC nor SOH significantly affect the specific heat capacity of lithium-ion cells.

Energy Storage and Applications doi: 10.3390/esa1010003

Authors: Klemens Jantscher Heimo Kreimaier Alem Miralem Christoph Breitfuss

In recent years, electric vehicles (EVs) have gained significant traction within the automotive industry, driven by the societal push towards climate neutrality. These vehicles predominantly utilize lithium-ion batteries (LIBs) for storing electric traction energy, posing new challenges in crash safety. This paper presents the development of a mechanically validated LIB module simulation model specifically for crash applications, augmented with virtual short circuit detection. A pouch cell simulation model is created and validated using mechanical test data from two distinct out-of-plane load cases. Additionally, a method for virtual short circuit prediction is devised and successfully demonstrated. The model is then extended to the battery module level. Full-scale mechanical testing of the battery modules is performed, and the simulation data are compared with the empirical data, demonstrating the model’s validity in the out-of-plane direction. Key metrics such as force-displacement characteristics, force, deformation, and displacement during short circuit events are accurately replicated. It is the first mechanically valid model of a LIB pouch cell module incorporating short circuit prediction with hot spot location, that can be used in full vehicle crash simulations for EVs. The upscaling to full vehicle simulation is enabled by a macro-mechanical simulation approach which creates a computationally efficient model.

Energy Storage and Applications doi: 10.3390/esa1010002

Authors: Yang Liu Songcen Wang Hongyin Chen Ming Zhong

Developing operation strategies for district cooling systems with chilled water storage is challenging due to uncertain fluctuations of cooling demand in actual operations. To address this issue, this paper developed an adaptive operation strategy and performed its validations by modeling and simulating a commercial cooling system in Shanghai using OpenModelica. Firstly, the originally designed operation strategy of the cooling system was evaluated by simulation but was found unable to meet the statistically averaged ideal cooling requirements due to the early exhaustion of stored chilled water at about 5:30 PM. Then, to build foundations for adaptive operation strategy development, a newly designed operation strategy was established by increasing the operation time of base load chillers in the valley and flat electricity price periods. The new strategy proved numerically sustainable in satisfying the ideal cooling demand. Moreover, to realize the strategy’s adaptability to actual cooling load fluctuations, an adaptive operation strategy was developed by tracking the target stored chilled water mass curve that was calculated by implementing the newly designed strategy. The simulation results verify that the adaptive operation strategy enables good adaptability to representative cooling load fluctuation cases by automatically and periodically adjusting the operation status of base load chillers. The adaptive operation strategy was then further widely numerically tested in hundreds of simulation cases with different cooling load variations. The time-lagging problem resulting in strategy failures was found in numerical tests and was addressed by slightly modifying the adaptive strategy. Results indicate that the adaptive operation strategy enables adaptability to deal with cooling demand fluctuations as well as allowing low cooling supply economic costs and power grid-friendly characteristics. This study provides theoretical support to strategy design and validations for district cooling system operations.

Energy Storage and Applications doi: 10.3390/esa1010001

Authors: Zhaoyang Dong

As sustainability and the adoption of renewable energy become increasingly prominent on the international agenda, energy storage plays an increasingly essential role in facilitating this transition while ensuring a secure and reliable energy supply [...]