Optimised capacity and operating strategy for providing frequency containment reserve with batteries and power-to-heat. (December 2020)

• Record Type: Journal Article
• Authors: Schlachter, Uli; Worschech, Alena; Diekmann, Theys; Hanke, Benedikt; von Maydell, Karsten
• Is Part Of: Journal of energy storage. Volume 32(2020)
• Publication Date: 2020-12
• Subjects: Primary control reserve -- Degrees of freedom -- Net present value approach -- Battery capacity sizing -- SoC management; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2020.101964
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Batteries provide growing amounts of Frequency Containment Reserve (FCR) in the German electricity market. We examine the ideal battery capacity as well as the state of charge (SoC) setpoint for provision of FCR following a profit maximisation approach. While a lot of research neglects taxes, their huge influence on the results is considered. In addition to stand-alone battery systems, we also consider hybrid systems, combining a battery storage with a Power-to-Heat (PtH) module. The hybrid system has two variants: in one variant energy is sold when the battery is fully charged, while in the other one the PtH module is used. Based on historical frequency and market data for one year, the performance of the different system variants is evaluated via a simulation. 2048 different combinations of battery capacity and SoC setpoint are examined. The performance of each configuration is evaluated with the net present value (NPV) method, allowing an economic comparison. The results show a financial advantage for the hybrid systems which sell energy when the battery is fully charged. The system configuration with the best NPV is a hybrid system with a battery capacity of 480 kWh and an SoC setpoint of 98%. The best battery capacity of all considered variants has a lower capacity to power ratio than the usual ratio of 1 MWh to 1 MW, assumed in most other studies. Non-optimal battery capacities have a stronger negative effect on the economic efficiency of the systems than non-optimal SoC setpoints. The results emphasise that the battery capacity is a critical investment decision. Highlights: Comprehensive study of optimal battery capacity and use of degrees of freedom. Combining a battery storage with a Power-to-Heat module provides economic benefits. Small battery capacity sufficient for Frequency Containment Reserve provision. Optimal use of degrees of freedom substantially improve the Net Present Value. Energy from Frequency Containment Reserve provision is sold for maximum revenue.