Technical-economic optimisation of the participation of a grid-serving large-scale battery in the primary balancing power market (Schachler et al. 2017)

The strong expansion of decentralised generation capacities results in an acute need for action to avoid local overloading of the distribution grids, which are designed to transport electricity to the consumer. Furthermore, in the medium term, there is the challenge of meeting the need for flexible, system-stabilizing services through appropriate measures. In this context, battery storage systems represent a technically very suitable and therefore attractive, but still little-tested solution option. As part of the SmartPowerFlow1 (SPF) project, a large-scale vanadium redox flow battery (VRF) was integrated into the power grid of a German grid operator for the first time. The battery system is a prototype whose inverter and battery control system were developed specifically for the project. The main objective of the project was to determine the extent to which the balancing act between economical and grid-supporting operation is possible. An analysis of possible business models for large-scale batteries has shown that under today’s framework conditions in Germany, the use of batteries in the primary control power market is by far the most lucrative area of application. Therefore, the focus of the project was on this business model. However, batteries that provide primary balancing power do not initially behave in a grid-friendly manner, as the charging and discharging of the storage system is determined solely by the grid frequency and not by the local grid situation. The grid-friendly nature of the battery under investigation was ensured by regulating the voltage in the local grid via a reactive power control in such a way that the grid absorption capacity for renewable energies is increased. In this way, a grid-serving and at the same time market-driven battery use could be combined.

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