Battery energy storage systems have gained increasing interest for serving grid support in various application tasks. In particular, systems based on lithium-ion batteries have evolved rapidly with a wide range of cell technologies and system architectures available on the market. On the application side, different tasks for storage deployment demand distinct properties of the storage system. This review aims to serve as a guideline for best choice of battery technology, system design and operation for lithium-ion based storage systems to match a specific system application. Starting with an overview to lithium-ion battery technologies and their characteristics with respect to performance and aging, the storage system design is analyzed in detail based on an evaluation of real-world projects. Typical storage system applications are grouped and classified with respect to the challenges posed to the battery system. Publicly available modeling tools for technical and economic analysis are presented. A brief analysis of optimization approaches aims to point out challenges and potential solution techniques for system sizing, positioning and dispatch operation. For all areas reviewed herein, expected improvements and possible future developments are highlighted. In order to extract the full potential of stationary battery storage systems and to enable increased profitability of systems, future research should aim to a holistic system level approach combining not only performance tuning on a battery cell level and careful analysis of the application requirements, but also consider a proper selection of storage sub-components as well as an optimized system operation strategy.

https://www.mdpi.com/1996-1073/10/12/2107/pdf

Lithium-Ion Battery Storage for the Grid—A Review of Stationary Battery Storage System Design Tailored for Applications in Modern Power Grids

Because of their characteristics, which have been continuously improved during the last years, Lithium-ion batteries have been proposed as an alternative viable solution to present fast-reacting conventional generating units to deliver the primary frequency regulation service. However, even though there are worldwide demonstration projects, where energy storage systems based on Lithium-ion batteries are evaluated for such applications, the field experience is still very limited. In consequence, at present, there are no very clear requirements on how the Lithium-ion battery energy storage systems should be operated, while providing frequency regulation service and how the system has to reestablish its state of charge (SOC) once the frequency event has passed. Therefore, this paper aims to investigate the effect on the lifetime of the Lithium-ion batteries energy storage system of various strategies for reestablishing the batteries’ SOC after the primary frequency regulation is successfully delivered.

Operation of a Grid-Connected Lithium-Ion Battery Energy Storage System for Primary Frequency Regulation: A Battery Lifetime Perspective

Battery energy storage system for primary control reserve and energy arbitrage

Regarding the supply of primary control reserve (PCR), stationary battery energy storage systems (BESS) are a promising alternative to fossil fuel power plants. They offer the ability to respond fast and precisely to grid frequency deviations and may contribute to reducing the must-run capacity of fossil fueled power plants. In Germany, primary control reserve is traded on a separate auction market with specific regulations, which enable the BESS to use a number of measures to balance its charge level and preserve operability. However, little is known about how the requirements from primary control deployment and the measures to keep the BESS operational during PCR contract periods affect operational parameters of the system. This study investigates the impact of operation strategies on different parameters including energy exchange through schedule transactions, total energy turnover, full cycle equivalents (FCE), and state-of-charge (SOC) distributions in a case study for a 2 MWh BESS under the German regulatory framework. The results of this study are key to the economic assessment of BESS providing PCR, to an optimization of BESS operation, and to an estimate of battery aging in this specific application field. Based on battery operation simulations, individual elements of operation strategies are identified and their influence on BESS operational parameters is analyzed in a parameter variation. These elements include the chosen measures for charge level management, the SOC ranges, within which these measures are used, parameters defining the schedule transactions, and the prequalified power rating of the BESS. The results show that the choice of the measures for charge level management, the choice of schedule transaction parameters and the prequalified power rating of the BESS have a major impact on energy exchange through schedule transactions. The choice of the measures for charge level management and the choice of schedule transaction parameters have limited influence on the total energy turnover and the resulting number of FCE. These values are mainly influenced by the system design.

Impact analysis of different operation strategies for battery energy storage systems providing primary control reserve

Renewable energy sources as a new participant in ancillary service markets

An increasing number of energy storages will be installed in buildings with photovoltaic systems. However, batteries with only local operation tasks do not exhaust their technical potential. Using the available battery capacity in terms of power and energy to provide ancillary system services is therefore economically reasonable. Providing primary control reserve power in combination with increasing local self-sufficiency has been identified as a promising option for decentralised PV battery systems. Thereby, part of the battery capacity is used to provide grid services and the remaining part for the management and optimisation of local system operation. Provision of self-sufficiency increase is limited, when the battery's state of charge is within certain limits. In this study, it is shown that the simultaneous use of the battery to locally increase self-sufficiency reduces the need for external power sources to correct the storage level. The operational concept, the technical solutions, and a sensitivity analysis are presented. Furthermore, billing and measuring issues as well as the current regulatory framework conditions in Germany are discussed.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-rpg.2015.0147

Distributed solar battery systems providing primary control reserve

Optimal Provision of Primary Frequency Control with Battery Systems by Exploiting All Degrees of Freedom within Regulation

The successful transition from a system based on conventional power plants to one based on distributed and renewable power generators requires an adopted system for the provision of ancillary services. Batteries are an option for such provision. Within this paper the cost structure differences between generators and batteries providing PCR are discussed. The latter is simulated in detail to quantify its costs. A battery system providing 1 MW of PCR is proposed. The system needs a nominal power of 1250 MW to maintain its state of charge. It was found that energy costs for corrective measures are much smaller than degradation costs for the battery system. The cost comparison between conventional power plants and the battery system shows significant differences in magnitude and dependencies to the wholesale markets. New competitive participants in the market can have important effects on today's providers and future PCR prices.

Luis Miguel Diazgranados

Papers

Distributed solar battery systems providing primary control reserve

Optimal Provision of Primary Frequency Control with Battery Systems by Exploiting All Degrees of Freedom within Regulation

Trends in the German PCR market: Perspectives for battery systems