Requirements for stationary application batteries

Expanding the adoption of PV generation, the primary renewable energy source, and promoting electrification on the critical side are key to achieving carbon neutrality in Japan's power system. However, while stationary energy storage systems are being introduced to stabilize grid frequency fluctuations caused by large-scale PV generation, frequent charge-discharge cycles solely using battery energy storage system to counter highfrequency grid fluctuations from sudden PV output variations accelerate equipment aging and increase maintenance costs. This paper proposes a novel approach: introducing the “Multi-Tiered Output Control Strategy for Hit Pumps” as a control strategy for demand-side controllable loads. This strategy coordinates with grid frequency regulation battery energy storage system to maintain supply-demand balance. This enables the utilization of solar power as a primary power source while reducing the required capacity of costly stationary battery energy storage system. It contributes to frequency control and promotes the widespread adoption of renewable energy.

Lithium-ion batteries are used for both stationary and mobile applications. While in the automotive industry standard profiles are used to compare the performance and efficiency of competing vehicles, a similar comparative metric has not been proposed for stationary battery energy storage systems. Because standard profiles are missing, the comparable evaluation of different applications with respect to efficiency, long-term behavior and profitability is very difficult or not possible at all. This work presents a method to create these standard profiles and the results are available as open data for download. Input profiles including frequency data, industry load profiles and household load profiles are transformed into storage profiles including storage power and state of charge using a holistic simulation framework. Various degrees of freedom for the energy management system as well as for the storage design are implemented and the results are post-processed with a profile analyzer tool in order to identify six key characteristics, these being: full-equivalent cycles, efficiency, depth of cycles, resting periods, number of changes of sign and energy throughput between changes of sign. All applications examined in this paper show unique characteristics which are essential for the design of the storage system. E.g., the numbers for annual full-equivalent cycles vary from 19 to 282 and the efficiency lies between 83% and 93%. With aid of this work in conjunction with the open data results, users can test and compare their own cell types, operation strategies and system topologies with those of the paper. Furthermore, the storage power profiles and state of charge data can be used as a reference for lifetime and profitability studies for stationary storage systems.

To address regional blackouts in distribution networks caused by extreme accidents, a collaborative optimization configuration method with both a Mobile Energy Storage System (MESS) and a Stationary Energy Storage System (SESS), which can provide emergency power support in areas of power loss, is proposed. First, a time–space model of MESS with a coupled transportation network and power grids is constructed, as a MESS is more flexible than a SESS. Considering resilience and recovery, a minimization objective function for total cost, encompassing the hybrid energy storage investment cost, the power grid operation cost, and the load shedding penalty cost, is established. Moreover, considering SESS constraints and operational constraints, a hybrid configuration model is established. Then, considering the probability of extreme accidents, the scenario analysis method is used to address randomness, ensuring that the configuration results can be adapted to various scenarios. The proposed method can fully combine the time–space flexibility of MESS and the economic advantages of SESS, which can reduce the total cost and ensure the power system’s reliability. Finally, the effectiveness of the proposed method is verified by the improved IEEE33 system.

Nasicon-type phosphates as electrode materials for safe and efficient electrochemical energy storage

The need of sustainable and efficient energy storage devices is an urgent need of modern society. The renewable energy production is characterized by an intermittent power output, and needs, for large scale applications, an improvement on the capability of energy storage (currently less than 1% of the energy production can be stored) 1. The development of low cost and environmentally friendly electrochemical storage systems characterized by high performances is of fundamental importance for a sustainable energy economy. The currently most mature battery technology is the lithium ion battery, considered the one of most appealing candidate as power source for electric vehicle application. Unfortunately, the large scale application of lithium ion batteries is nowadays under discussion, due to the limited amount of lithium resources2. Several other metal anodic materials such as sodium3, potassium4, calcium5, magnesium6 and aluminum7, characterized by a higher abundance with respect to lithium, have been considered as suitable candidates for electrochemical storage devices in replacement of lithium systems. In particular aluminum, the most abundant metal element in the earth’s crust, is considered a promising candidate for application in stationary electrochemical storage systems. The light weight of aluminum and its ability to exchange three electrons during the electrochemical process (Al3+ + 3e- ↔ Al) grant both, a high gravimetric and volumetric capacity density of 2.98 Ah g-1 and 8.04 Ah cm-3, respectively, the latter value being four times higher as compared to a lithium metal anode. Additionally, the aluminum can be handled in open air leading to enormous advantages in the cell fabrication and an extreme improvement of the safety level of electrochemical storage systems employing this electrode material. In our work we propose the use of a Al2(WO4)3 as an alternative cathode material for the application in aluminum batteries. This material is characterized by a theoretical capacity of 202 mAh g-1 for complete de-intercalation of the aluminum from the structure. Electrochemical tests have been performed employing 1-ethyl-3-methylimidazolium chloride (EMImCl) ionic liquid and AlCl3 in a molar ratio of EMImCl:AlCl3 1:1.5 as the electrolyte. The suitability of the electrolyte media against aluminum metal has been evaluated by means of impedance spectroscopy as well as of cyclic voltammetry, revealing the reversibility of the electrochemical process of stripping and deposition of the aluminum in the employed cell configuration. The reversibility of the electrochemical intercalation of the Al3 + ion in the Al2(WO4)3cathode material has been demonstrated by cyclic voltammetry as well as galvanostatic cycling tests that reveal a good electrochemical performance of the investigated material.

Experimental study of a DC charging station for full electric and plug in hybrid vehicles

W artykule przedstawiono zmiany jakie nastąpiły w zakresie produkcji energii elektrycznej z odnawialnych źródeł energii w krajach UE-28 oraz w Polsce w latach 2010-2015. Analizę zmian przeprowadzono na podstawie danych z Eurostatu oraz Banku Danych Lokalnych. W oparciu o wskaźnik określający udział energii elektrycznej wytwarzanej ze źródeł odnawialnych w zużyciu energii elektrycznej brutto wykazano, iż Polska charakteryzowała się w omawianym okresie jedną z najwyższych dynamik zmian spośród wszystkich państw UE. Ponadto w artykule zanalizowano sytuację dotyczącą produkcji energii elektrycznej w Polsce w przekroju regionalnym. Z podjętych w tym zakresie analiz wynika, iż we wszystkich województwach oprócz małopolskiego w 2015 r. produkowano więcej energii elektrycznej ze źródeł odnawialnych w porównaniu do 2010 r. W omawianym okresie również o 99% wzrósł w Polsce udział produkcji energii elektrycznej ze źródeł odnawialnych w produkcji energii elektrycznej ogółem.

This paper presents an energy management system for a Net-Zero Energy House. The house is equipped with photovoltaic panels on the roof, a stationary energy storage system, and a Battery Electric Vehicle. The energy management strategy aims to minimize the house interaction with the power grid, enabling internal power flow without impacting upstream of the point of common coupling. The goal is to ensure that the house predominantly operates as a self-sufficient energy system, with the capability to even inject surplus energy back into the grid. The proposed topology and operation strategies are presented and validated through simulation results. Key words. nZEH, PV panels, stationary battery electric vehicle.

China, faced with an exponential growth of domestic energy consumption today, has strived to facilitate the use of renewable energies across the country as a national project to diversify energy sources. The project has been so far successful and China is now witnessing a remarkable surge of the use of renewable energies across multiple sectors. A crucial part for this success has been played by successive legislation encouraging the use of renewable energies, but in the process some disagreement on several key issues was observed among government departments and stakeholders involved. This paper examines the legislation process of 'Renewable Energy Law' before turning to the continuing controversy over whether the Law includes hydro power, and to the issue of interest conflicts among the ministries surrounding renewable energy policy. The final decision on the matter of whether water power is subject to the Law is now referred to the State Council. Renewable energy policy is officially supposed to be controlled by the National Energy Commission, but the National Development and Reform Commission, as a higher authority supervising it, exerts a great influence on its policy making and implementation.Deprived of much autonomy under this bureaucratic hierarchy, the National Energy Commission has little ability to create and carry out sustainable energy policy. This is especially so given the fact that the National Development Reform Commission by its very nature is more concerned with economic growth than environmental protection. With the use of renewable energy expected to grow continuously into the future, this is highly likely to pose a long-term threat to the administration system, and thus active efforts should be made to ensure that the roles are clearly defined and properly distributed among government bureaucracies.

3 - Applications of nuclear science and radioisotopes technology in power generation, hydrogen economy, and transport

Grid operators are charged not only by their total energy demand, but also by their highest power demand from the superior grid level. The maximum demand charge is usually imposed on the peak power point of the monthly load profile, hence, shaving demand at peak times is of main concern for the aforesaid stakeholders. In this paper, we present an approach for peak shaving in a distribution grid using a battery energy storage. The developed algorithm is applied and tested with data from a real stationary battery installation at a Swiss utility. This paper proposes a battery storage control scheme that can be used for peak shaving of the total grid load under realistic conditions. Particularly, a rule-based approach combined with a deep-learning load forecasting model is developed and its performance is compared with the theoretical optimum based on real data from the field. The analysis includes both technical and economical results from a simulated storage operation and significant outcomes are given for the application of this method.

Fusion estimation of lithium-ion battery state of charge and state of health considering the effect of temperature

The rapid development of electric vehicles (EVs) increases the power demand, which causes an extra burden on the public grid, increasing the load fluctuations and, therefore, hindering the high penetration of EVs. In this paper, a real-time rule-based algorithm for electric vehicle (EV) charging stations empowered by a direct current (DC) microgrid is proposed. Such a DC microgrid model consists of EVs, an electrochemical storage system, a public grid connection, and photovoltaic sources. The EV charging station model is based on data-driven modelling while its management model takes into account discrete events. This paper focuses on power management strategy of an EV charging station under power limitation and considers most of the drivers’ choices. The EV charging system topology is presented and common problems during an EV charging process are discussed, e.g., disconnection operation, standby mode, shedding, and restoration operation. Furthermore, the proposed power management deals with the uncertainties of EV drivers’ behavior considering arbitrary and random choices through the human–computer interface. The simulation results obtained under MATLAB/Simulink verify the feasibility of the proposed management strategy that presents a good performance in terms of precise control.

Sustainable microgrids with energy storage as a means to increase power resilience in critical facilities: An application to a hospital

Challenges and prospects of electricity production from renewable energy sources in Slovenia