A day ahead scheduling model of a smart hydrogen-based microgrid taking into account PV production and electrical load demand forecasting errors

Long-term storage systems are being studied as one option to ensure cost-efficient and reliable operation of future, highly decarbonized energy systems with a high share of variable renewable energy sources. In this paper, we analyze whether and under which circumstances a trade-off between long-term energy storage systems and transmission capacity expansion can exist. We investigate this trade-off using a greenfield generation and transmission expansion model inspired by a Central Western European case study. We address parametric and structural uncertainties by comparing different scenarios and exploring near-optimal solutions using modelling-to-generate-alternatives. Results indicate that a trade-off can exist between long-term storage system deployment and transmission capacity expansion. The extent of this trade-off depends largely on cost assumption with regards to the storage energy capacity costs, on weather assumptions, and on the considered near-optimal search space.

This study investigates innovative solutions for balancing energy supply and demand using long-term thermal energy storage (TES) systems, with a focus on tank thermal energy storage (TTES) for European buildings, which account for approximately 40% of energy consumption in the European Union. Research conducted at the Technical University of Košice explores the potential of TTES systems for efficient and long-term energy storage. The accumulation is carried out in three existing underground tanks of different volumes. Among various outputs, we present the cooling process resulting from covering the water surface and the effect of tank size on cooling. The findings indicate that covering the water surface in the tanks can effectively double the energy retention time, thereby extending the cooling period. A tank with a larger volume cools slower and better ensures the formation of temperature layers. Temperature layering allows for better utilization of the tanks’ potential in terms of energy. The overall result is a significant reduction in heat losses and CO₂ emissions. These results demonstrate the critical role of TTES in stabilizing renewable energy sources, especially solar energy, to support sustainable energy solutions in buildings by providing reliable and long-term energy storage.

Increasing penetration of intermittent Renewable energy sources (RESs) and advanced technologies in the power systems has increased the complexity of its management. The futuristic grid operation would require several options like increasing generation, transmission capacity, grid-scale storage, backup support, demand-side-management, and virtual energy storage systems for efficient operation. Of all the above, a grid-scale long-term storage system is a feasible solution for better grid operation utilizing seasonal intermittent renewable resources. Recently, hydrogen as a fuel has become an omnipresent thing. Even in power systems, it is gaining much acceptance for its usage as long-term storage, offering better techno-economic solutions. As this technology is still at a developmental stage, a proper understanding of different facets of the whole system certainly helps to research further in this field. So, this paper briefly reviewed long-term hydrogen storage (LTHS) systems by discussing their components, usage, and energy management techniques with their financial feasibility considerations, which were not found in the literature. Furthermore, this manuscript also provides a detailed analysis of the storage system business models and a brief current worldwide scenario for the upcoming times to increase its practical scalability and further research.

The future electric power system: Impact of Power-to-Gas by interacting with other renewable energy components

This paper presents a novel analytical method for electro-mechanical design of a high speed long-term flywheel energy storage system and thermal evaluation of possible operating modes of the system. Flywheel's composite shell rotor along with the motor/generator unit are assumed to be placed into a sealed vacuum chamber, which presents a challenge of heat transfer, produced by rotor losses. Developed method takes into account thermal radiation properties of the rotor and is realised using Mathcad software, which allows for quick investigation of any flywheel configuration. The method involves calculations for preliminary rotor sizing and determining achievable operation modes, while keeping the rotor under a specified temperature limit. Results of using this method for studying dependencies of thermal performance on initial system parameters are presented and conclusions are drawn. Based on the conducted study, recommendations on system design considerations are given.

As global demand for renewable energy continues to grow, developing efficient, sustainable, and long-term energy storage systems becomes increasingly critical. Zinc-based liquid flow batteries have attracted much attention due to their high energy density, low cost, and environmental-friendliness. This review discusses the latest progress in sustainable long-term energy storage, especially the development of redox slurry electrodes and their significant effects on the performance of zinc-based liquid flow batteries. The redox slurry electrode can enhance charge transfer efficiency and promote chemical bonding between redox species and the carbon skeleton by combining low-density carbon materials with specific porosity and an optimized sp2/sp3 carbon ratio. These advances not only address the energy loss issue caused by the shuttling of redox species in traditional zinc-based flow batteries but also enhance the adsorption capacity of the electrode, improve battery charge and discharge stability, and extend cycle life effectively. Additionally, the application of low-cost choline salt water electrolytes in zinc-based liquid flow batteries is explored. This new electrolyte not only reduces the cost of the battery but also improves the safety and environmental compatibility of the system. By analyzing current research challenges and predicting future development directions, this paper aims to provide a comprehensive perspective for researchers and engineers to promote further innovation and application of zinc-based flow battery technology, particularly in sustainable energy storage. The development of redox slurry electrodes presents a new opportunity for enhancing the performance and expanding the applications of zinc-based liquid flow batteries, marking a significant milestone in sustainable, long-term energy storage solutions. With further research and technological advancements, zinc-based flow batteries are expected to play a key role in the global energy transition.

Digital chest radiography: quality assurance.

Special issue on “Optimal design and operation of energy systems”

Aphids are a valuable tool to study plant vascular tissue and plant responses to aphid feeding. A standard method of rearing aphids for use in education and research is to maintain active cultures in a greenhouse. While some studies have examined ways of providing long-term storage of parasitoids and pathogens of aphids, little has been done to lengthen the time aphids can survive without the need for researchers to provide the aphids with fresh host plants or to maintain the plants with water and fertilizer. Actively reproducing aphid colonies and their host plants must be replaced frequently to prevent overcrowding or colony collapse resulting from degradation of the quality of the plants feeding the colony. This arrangement may not be available for small-scale studies and is costly and cumbersome for multiple lines of aphids. Artificial diets are labor intensive, are most useful for providing a controlled environment to carry out tests on aphids, and are rarely, if ever, suitable for long-term colony survival. Issues present in actively growing cultures can be minimized. By reducing the amount of handling and providing only the small, easily sealed opening of a test tube for access to the aphids, colony contamination from other mobile aphids can be reduced. For example, contamination often occurs with bird cherry aphids (Rhopalosiphum padi L.) which have been noted as adept escape artists (Austin et al., 1991). By using cool temperatures to slow aphid reproduction, the occurrence of problems associated with parasitic wasps and predators such as lady beetles and spiders would also be reduced since threshold temperatures (roughly, the temperature at which development ceases) for parasites is generally higher than that of their hosts (Campbell et al., 1974). The cooler temperatures needed for prolonged aphid survival is not a concern for freezing injury of the plant: threshold temperatures for five different aphid genera ranged from 1.7 to 8.3uC (Campbell et al., 1974) while wheat and barley are killed at temperatures in the 220 to 210uC range (Metcalf et al., 1970). Long-term storage would also increase the number of lines that could be reared with a limited amount of resources. Previous work with greenbugs (Schizaphis graminum Rondani) and Russian wheat aphids (Diuraphis noxia Mordvilko) demonstrated the possibility of cultivating aphids in a test tube for at least four days (Miller et al., 1994). Other systems have been developed for maintenance of aphid colonies for at least a week (Austin et al., 1991) and in Europe an informal method allows for two-week storage in a cold room setting (S. Vidal, pers. comm.). This research was designed to develop an inexpensive test tube culture system for long-term (several week) aphid culture and storage that would not require maintenance or upkeep during the culture period. Materials and Methods S. graminum Biotype E cultures were obtained from USDA/ARS Wheat, Peanut and Other Field Crops Research Unit in Stillwater, OK, USA. R. padi were local, found in our own greenhouse in Stuttgart, AR, USA. Wheat seedlings, cv Ranger, were grown for host plants in a 1:1 (v/v) mix of silt-loam field soil and commercial potting soil in the laboratory under grow lights. Active aphid cultures were maintained on wheat plants and isolated by enclosure in a zippered net bag in order to minimize colony mixing, parasitism, and predation. To establish aphid cultures, three wheat plants approximately 15 cm tall with root and soil still attached were transplanted into a 2.0 3 15.0 cm glass test tube. The soil was moistened by adding enough water to saturate the soil but leave no free water. The tubes were maintained at room temperature (24uC) for two

Purpose: The demand for fertility preservation continues to grow as cancer treatment outcomes improve. The specimen storage period is longer for fertility preservation than for conventional fertility treatment; therefore, a robust management system for stored specimens is required. We conducted the first national survey in Japan on the management of cryopreserved specimens in fertility preservation facilities. Methods: Questionnaires were mailed to 130 fertility preservation facilities. Primary outcomes included the official position of the storage manager, support system in case of facility closure, disaster countermeasures, management and operating system for liquid nitrogen storage containers, preservation costs, and method to confirm the intention to continue storage. Results: The response rate was 63.8%. The facility director most commonly functioned as the storage manager (59.0%). In case of facility closure, 20.5% had an approved transfer site; 59.0% had not made any decisions. In the management of liquid nitrogen containers, 83.1% regularly replenished the liquid nitrogen, 65.1% regularly checked the amount, and 16.9% had alarm monitoring systems. Regarding disaster countermeasures, 70.9% had taken measures to protect specimens. Conclusion: This survey revealed issues such as disparities among facilities regarding long-term specimen storage systems. Accordingly, management standards for fertility preservation facilities should be established.

Aim: In molecular biology, there is a need for tissue storage solutions for long term analysis in order to have a suitable source of nucleic acids (RNA and DNA). There are many reports to store the tissue samples in different solutions like ethanol, DMSO as well as with storage in liquid nitrogen, but a suitable storage solution for tissue at room temperature is still missing. Therefore, a solution called Genekam Tissue Storage Solution (GTSS) is developed, which can be used to store the tissues at room temperature for a long time. Materials and Methods: Human tissues were stored in this solution for 4 years. as these are tested with conventional and real time PCR for the presence of internal controls after the isolation of RNA and DNA over the period of 4 years, along with spectrometric testing. Results: Results of internal controls for human housekeeping genes like beta-globin and beta-actin were successful in nucleic acid isolations. Spectrophotometric values of all nucleic acid isolation range from 1.03 to 33.8 ng/µl (1.03 to 33.8 µg/ml). Conclusion: In this work, it may be the first time about the successful development of a simple long-term noncryogenic storage solution for human tissues at room temperature as a continuous source of DNA and RNA for molecular biological analysis.

A calcium looping system powered by renewable electricity for long-term thermochemical energy storage, residential heat supply and carbon capture

The importance of energy storage is steadily rising as electricity grids around the world become more reliant on intermittent renewable power sources such as solar PV and wind turbines. Apart from pumped hydro storage, which forms the bulk of existing energy storage, several other technologies are in development, such as batteries, super-capacitors, flywheels and synthetic e-fuels. Li-ion batteries are highly efficient and dynamic, while e-fuels have many advantages for large-scale seasonal storage. Reversible solid oxide cells (rSOC) are efficient electrochemical devices, which can play an important role in energy storage in the form of e-fuels in the near future. This paper seeks to show the advantages of rSOC systems in long-term energy storage. In particular, it seeks to compare the capital cost of a hybrid system to a purely Li-ion battery system.This paper focuses on the design of energy storage for isolated sustainable micro-grids. A hybrid system is designed, using Li-ion batteries for instantaneous grid balancing, and rSOC system for long-term storage in the form of hydrogen. The paper also focuses on the effect of the wind-solar energy mix and climate. For temperate and cloudy climates, Groningen in the Netherlands is used as an example. The Netherlands has a renewable energy mix of around 70% wind and 30% solar. For sunny tropical climates, Jodhpur in India is used, and India has a renewable energy mix of around 55% wind and 45% solar. Using hourly local data for solar irradiation and wind velocities, a simple algorithm is developed for system sizing. The generation as well as storage systems are sized for a constant consumption load of 20 kW (a constant load is considered to be a reasonable assumption for industrial loads, for example). The capital cost calculation includes the wind turbine(s), solar panels, battery bank, rSOC stack, and compressed hydrogen tank.The results show that the use of an rSOC-hydrogen module in a hybrid-energy storage system leads to significant capital cost reduction compared to a purely Li-ion battery-based system. As expected, this reduction is a result of the fact that power and energy-storage capacities are decoupled in an rSOC/e-fuel system, which means that a small rSOC stack can be used with a large tank, which is suitable for long-term seasonal storage. Hydrogen tanks also cost significantly less than batteries for the same energy capacity. The cost reduction for Jodhpur is more significant than for Groningen.The study also shows the significant effect of the local energy mix on the design of energy storage systems. Naturally, Jodhpur has more solar radiation and less seasonal variation in solar energy. But contrary to initial expectations, tropical Jodhpur requires larger energy seasonal storage facilities than temperate Groningen. This is because the small seasonal solar variation in Jodhpur is further compounded by the seasonal wind pattern, where the wind is strong in summer and weak in winter. On the other hand, the wind patterns are much more stable in Groningen, which largely neutralises the solar variation, especially since wind makes up 70% of the energy mix in Groningen. Figure 1

The aim of this paper is to evaluate and to describe a Stand-alone renewable energy system (SRES). This latter is composed of three components, namely solar energy system (SES), a proton exchange membrane fuel cell (PEMFC) and a supercapacitor device (SCap). As a primary power source of the concerned system, the SES releases firstly the necessary of power to a DC load. A proton exchange membrane electrolyzer (PEMEL) is considered a long-term storage system that stores the surplus of energy generated by the SES system in hydrogen form. Used as a power generation system, the PEMFC ensures the supply of the load in the event of power failure. The integration of the SCap ensures the elimination of the slow dynamics of the PEMFC during transient event. A novel Energy Management Controller (EMC), which serves to the system handling, is proposed. Simulation results obtained using Matlab/Simulink software are presented to verify and to point out the validity of the proposed system.

Long-term storage of seasonally available solar energy and its provision to balance heating energy demand can contribute significantly to the sustainable use of energy resources. Thermochemical energy storage is a suitable process for this purpose, offering the possibility of loss-free long-term energy storing and heat supply. In order to develop suitable technical solutions for the use of this technology, novel reactor concepts and scientific questions regarding material and technology development are being investigated. In this publication, the energy storage process of a long-term energy storage system based on a ploughshare reactor is experimentally investigated under various technically relevant operating conditions. One specific aspect of this technology is related to the release of water vapour during the charging process. Therefore, this work focusses, in particular, on the possibility of technically utilizing the latent heat of the released water vapour in the range of 45 °C to 80 °C, which covers the operating requirements of common heating systems in households. The experiments have shown that the dehydration process enables the separation of two heat fluxes: the chemically bound energy for long-term storage and the physically (sensible and latent) stored energy for short-term applications. However, the limitation of gas transport was also identified as the most important influencing parameter for optimising the performance of the process.