Transitioning to net-zero requires replacing traditional thermal power plants with solar and wind farms. Unlike thermal plants, renewable sources generate direct current (DC), which inverters translate to alternating current (AC). When connected to the grid, inverters operate at 50 Hz, maintained by conventional power plants. As the share of conventional generators decreases, maintaining grid frequency becomes more challenging.  Grid-forming (GFM) inverters for battery energy storage systems (BESS) can help to maintain grid frequency by preserving required system inertia levels. Clear technical regulations are essential to enable Grid-forming inverters in BESS to provide inertia services.

The reduction in inertia results in faster frequency dynamics, higher rates of change of frequency (RoCoF) and reduced stability margins following a disturbance. Frequency events can now occur in fractions of a second, requiring faster activation of reserves and more responsive control systems. This presents the following challenges to grid operators:

• Mitigating rapid frequency changes: Maintaining inertia slows the rate of change of frequency (RoCoF) following disturbances, providing crucial time for reserves to respond and prevent cascading failures.

• Enhancing frequency stability: Maintaining inertia levels supports system frequency by instantly supplying or absorbing energy during generation-demand imbalances, reducing the risk of frequency instability and system splits.

• Facilitating effective integration of renewables: Maintaining inertia by GFM in BESS compensates for the lack of inherent inertia in inverter-based renewable sources, enabling stable operation as synchronous machines are retired.