A closed-loop analysis of grid scale battery systems providing frequency response and reserve services in a variable inertia grid

Abstract

With increasing penetration of wind and solar generation the deployment of fast response plant, principally batteries, is currently considered necessary to mitigate reduced system inertia and the possibility of demandsupply imbalances. In this work the impact of these factors on battery cycling rates, taking into account the input from the batteries themselves, are analysed by applying the swing equation to a future inertia based on forecast generation mix. The operational capacity of batteries is a determining factor in their cycling rate, though the depth of discharge appears to be less well correlated. It is found that reducing system inertia does not, of itself, significantly impact on frequency volatility where the volatility of the generation to load imbalance is unchanged. However, the potential for a reduction in the damping of frequency deviations as a result of an increase in inverter connected motor drives may have a large impact on battery cycling characteristics. Provision of reserve services from battery systems requires a more complex operational strategy to ensure services are always deliverable and results in a significantly different cycling profile that may lead to greater battery degradation and consequently higher operational costs.

Pricing inertia and Frequency Response with diverse dynamics in a Mixed-Integer Second-Order Cone Programming formulation

“…The time within this first time-interval at which nadir is exactly reached is given by solving (6) for that particular time-interval:…”

“…The authors in [4] studied secondary FR coordination from industrial loads and thermal generators, while [5] focused on the coordination of electric vehicles and thermal units to provide response. Studies on the provision of FR from novel devices are also widely available, such as [6] for battery storage and [7] for electric vehicles.…”

Validating the Real-Time Performance of Distributed Energy Resources Participating on Primary Frequency Reserves

“…Other authors apply heterogeneous approaches for real-time grid impacts assessment. Lee et al [24] analyze the impact of large-scale deployment of battery reserves to reduce frequency volatility. Although this demonstrates some beneficial grid impacts, these works do not address PFR market operators' technical requirements.…”

Inertia Response Coordination Strategy of Wind Generators and Hybrid Energy Storage and Operation Cost-Based Multi-Objective Optimizing of Frequency Control Parameters

“…Modern societies are moving toward the use of renewable energy sources [6]. These sources are connected to the grid with power electronic based interfaces [7][8][9]; however, the high penetration of renewable energy sources may impose challenges to critical frequency stability. Generally, renewable energy resources have little or no inertial response.…”