Synthetic Inertia

Synthetic inertia refers to the fast frequency response provided by inverter based resources that emulate the inertial behavior of synchronous machines. When system frequency deviates, control algorithms within wind turbines, solar inverters, or battery systems inject or absorb power for a few seconds to arrest the rate of change. This capability compensates for the declining mechanical inertia that accompanies high renewable penetration.

Implementing synthetic inertia requires precise measurement of grid frequency and high speed control loops that can deliver power without destabilizing the inverter. Manufacturers tune response curves to coordinate with protection settings, ensuring that synthetic inertia complements rather than conflicts with governor response from thermal units. Some jurisdictions now mandate minimum synthetic inertia capability within grid codes.

Because synthetic inertia consumes stored kinetic or electrical energy, plant operators must manage state of charge and thermal limits to provide these services reliably. Hybrid plants often dedicate a portion of battery capacity to support synthetic inertia while the remainder pursues energy arbitrage or capacity revenues. Utilities evaluate how these services interact with other grid forming requirements and remedial action schemes.

Pilot projects in Australia, Europe, and North America are proving that synthetic inertia can maintain frequency stability even after large generator trips. Lessons from these deployments feed into updated interconnection requirements, creating new revenue opportunities for storage integrators and OEMs that can certify performance.