As the world accelerates toward building a new power system dominated by renewable energy, energy storage has become an indispensable foundation. However, with the rising penetration of solar and wind power, the grid is facing severe stability challenges such as reduced inertia and increased fluctuations. Traditional grid-following energy storage systems can only passively adapt to the grid and struggle to provide support when the grid is weak or faulted. At this moment, a technology known as grid-forming is driving a revolutionary shift in the core device of energy storage systems—the power conversion system (PCS)—from passive following to active support, becoming a true “stabilizer” for grid security.
1. Why Do We Need Grid-Forming Energy Storage?
The stability of traditional power systems relies on the physical inertia produced by the rotating mass of synchronous generators. Renewable sources like PV and wind, however, connect to the grid via power electronics and inherently lack this capability. When the proportion of these renewable sources becomes too high, the grid becomes “soft” and fragile, easily leading to voltage and frequency instability—and in severe cases, large-scale blackouts.
Traditional grid-following PCSs act like precise “energy transporters,” relying on the grid to provide stable voltage and frequency references. Once the grid signal disappears or a fault occurs, the PCS loses its reference point, and may even disconnect—failing to provide support exactly when the grid needs it most.
Therefore, we urgently need an energy storage system capable of independently establishing stable voltage and frequency references. Grid-forming storage emerges as the solution. Its core lies in enabling the PCS to emulate the behavior of synchronous generators—transforming it from a “grid follower” into a “grid builder and supporter.” This is not just a technological upgrade, but a necessary path to meeting the challenges of high-renewable-penetration power systems.
2. What Is a Grid-Forming Energy Storage Converter?
A grid-forming PCS is the heart of a grid-forming energy storage system. The fundamental difference from traditional converters lies in its control strategy. Traditional converters operate as current sources, with output that follows the grid voltage. In contrast, grid-forming converters operate as voltage sources, capable of independently generating voltage and frequency references—effectively establishing a stable, self-governed “microgrid.”
This gives the system characteristics similar to conventional thermal power units. For example, in a demonstration project in Shandong, a grid-forming PCS successfully provided “black start” power for a 410 MVA gas turbine, establishing voltage from zero under a complete blackout and withstanding large inrush currents—showcasing strong active support capabilities.
3. What Can Grid-Forming Energy Storage Converters Do?
The value of grid-forming storage spans the entire power system—from generation, transmission, and distribution to consumption. Its core functions appear in three key areas:
1. Strengthening Grid Resilience and Withstanding Extreme Faults
During grid disturbances, grid-forming storage can deliver short-circuit support up to three times its rated current, helping maintain power to critical loads. More importantly, it provides black start capability—from minutes to even seconds—serving as a “start-up power source” to rapidly restore local or regional supply after a total blackout.
2. Enhancing Renewable Energy Integration and Export Capability
In weak-grid regions or large renewable bases, insufficient grid strength often limits PV and wind output. Grid-forming storage can actively reinforce voltage at the point of interconnection, effectively “strengthening” the grid. For instance, in the high-altitude Ali project in Tibet, grid-forming storage increased the PV plant’s output by 75%, greatly improving energy export performance.
3. Providing Essential Ancillary Services for the New Power System
Grid-forming storage offers high-quality virtual inertia and fast frequency response, smoothing renewable fluctuations with reaction speeds far superior to traditional units. This elevates energy storage stations from simple “power banks” to strategic regulation assets participating in real-time grid dispatch—ensuring safe and efficient grid operation.
Conclusion
The evolution of grid-forming PCS technology marks a profound shift in the role of energy storage—from simply storing energy to delivering core services for grid stability and resilience. In the future, competition among energy storage systems will extend far beyond battery cost and cycle life. Instead, it will focus on the depth of grid-forming capability as an intelligent grid node. Mastering grid-forming converter technology will be essential to supporting the energy transition and building a safer, more flexible, and more intelligent power system.
If you’re interested in grid-forming energy storage converters, feel free to contact our technical experts today for a free customized system selection analysis and solution proposal—let professional insights empower your decisions.
