Overview of current development in electrical energy storage technologies and the application potential in power system operation

Energy storage technologies and real life applications – A state of the art review

Grid-scale energy storage systems (ESSs) that can connect to sustainable energy resources have received great attention in an effort to satisfy ever-growing energy demands. Although recent advances in Li-ion battery (LIB) technology have increased the energy density to a level applicable to grid-scale ESSs, the high cost of Li and transition metals have led to a search for lower-cost battery system alternatives. Based on the abundance and accessibility of Na and its similar electrochemistry to the well-established LIB technology, Na-ion batteries (NIBs) have attracted significant attention as an ideal candidate for grid-scale ESSs. Since research on NIB chemistry resurged in 2010, various positive and negative electrode materials have been synthesized and evaluated for NIBs. Nonetheless, studies on NIB chemistry are still in their infancy compared with LIB technology, and further improvements are required in terms of energy, power density, and electrochemical stability for commercialization. Most recent progress on electrode materials for NIBs, including the discovery of new electrode materials and their Na storage mechanisms, is briefly reviewed. In addition, efforts to enhance the electrochemical properties of NIB electrode materials as well as the challenges and perspectives involving these materials are discussed.

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Recent Progress in Electrode Materials for Sodium-Ion Batteries

Overview of energy storage in renewable energy systems

Thermal energy storage systems are key components of concentrating solar power plants in order to offer energy dispatchability to adapt the electricity power production to the curve demand. This paper presents a review of the current commercial thermal energy storage systems used in solar thermal power plants: steam accumulators and molten salts. It describes the mentioned storage concepts and the results of their economic evaluation. The economic value of the TES system is assessed by the Levelized Cost of Electricity (LCOE) calculation, an economic performance metric commonly used in power generation in order to compare cost of electricity among different power generation sources. Lots of studies have been done in the past to compare the LCOE of a complete solar thermal power plant using thermal energy storage systems. However, no specific studies related to the thermal energy storage levelized cost of electricity itself were done. The objective of this study is focused in the comparison of the TES LCOE where calculations are done for a 100 MW Rankine cycle with different plant configuration and for different storage sizes ranging from 1 to 9 h of equivalent full capacity operation.

Review of commercial thermal energy storage in concentrated solar power plants: Steam vs. molten salts

Review of energy storage system for wind power integration support

Digital real-time co-simulation platform of refined wind energy conversion system

Fast development of High Voltage Direct Current (HVDC) technology has been remarkable over the past decades. Multi-terminal HVDC grids based on Voltage Source Converters (VSC) are promising solution to connect multiple asynchronous power grids, as well as integrate large-scale renewable energy sources e.g. offshore wind farms. New generation of the VSCs, Modular Multilevel Converter (MMC), offers considerable benefits. However, protection has always been a great challenge for the VSC-HVDC transmission systems, in particular, for the multi-terminal DC grids. This paper presents an insightful survey considering protection strategies for MMC-HVDC grids. The study sheds light on state-of-the-art of protection scheme including fault identification and interruption methods for the MMC-HVDC systems. Moreover, a short discussion regarding HVDC grid topologies and control has been presented to investigate their impacts on protection and security of the VSC-HVDC grids. Investigation of Fault-Ride-Through (FRT) capability is vital to be included in protection coordination strategies under DC fault conditions. Possibility of having different DC FRT capabilities for different structures of the MMCs is investigated. In addition, pros and cons of protection strategies are presented and discussed comprehensively.

Protection System of Multi-Terminal MMC-based HVDC Grids: A Survey

HVDC transmission systems are an attractive option for transmitting bulk power through long distance. Protection of HVDC grids plays a major role to have a secure and reliable power delivery to customers. However, design of DC protection has always been a challenge. On the other hand, transient stability of AC/DC grid is important, especially when it comes to situations with faults. The AC/DC grid should keep its stability during and after DC fault interruption. Based on grid characteristics and dynamics, there can be different solutions and circuit breaker selection for different HVDC grids. An effective design of DC protection can reduce system cost, while assuring system security at the same time. This study investigates design of HVDC protection considering system transient stability. The paper presents a method to select appropriate circuit breakers based on transient stability of AC/DC grid. The proposed method can keep transient stability under DC fault condition while avoiding over-qualified and more expensive DCCBs. Different simulation tests have been performed in PSCAD platform and test results are discussed in this study.

Shuju Hu

Papers

Review of energy storage system for wind power integration support

Digital real-time co-simulation platform of refined wind energy conversion system

Protection System of Multi-Terminal MMC-based HVDC Grids: A Survey

DC Protection Design for VSC-HVDC Systems Based On Transient Stability Issue

Dc Protection Coordination for Multi-Terminal Hb-Mmc-Based Hvdc Grids