Understanding Grid-Forming Energy Storage: The Ultimate Stabilizer for New Energy Power Grids

In the new energy era, the power grid lacks a 'critical short board.' Wind and PV power stations are now everywhere, gradually replacing traditional thermal and hydropower, helping the power industry achieve low-carbon transformation. But many people do not know: large-scale new energy grid connection brings a fatal problem to the grid — traditional thermal power is the grid's 'ballast stone,' capable of stabilizing voltage and frequency, while wind and PV have inherent 'instability' and cannot support grid stability.

As thermal power gradually exits and new energy increasingly connects, the grid becomes more and more 'buoyant,' with dramatically increased risks of fluctuation, oscillation, and blackouts. The core answer to solving this industry pain point is the hot new core technology in the new energy sector — Grid-Forming Energy Storage.

Part 1: Basic Understanding — What is Grid-Forming Energy Storage?

1.1 Core Plain-Language Definition

Energy storage systems are mainly divided into two major categories: Grid-Following Storage (traditional) and Grid-Forming Storage (new).

In simple terms, grid-forming energy storage is an energy storage system that can independently build and stabilize a power grid. It abandons the traditional mode of 'following the grid' and can, like traditional thermal generators, proactively establish and maintain the grid's voltage and frequency — without relying on external grid signals.

Plain summary: When connected, it helps stabilize grid voltage and frequency. When power is lost and disconnected, it can independently supply power — combining 'auxiliary support' and 'independent power generation' in one.

1.2 Grid-Following vs. Grid-Forming — Core Differences at a Glance

One-sentence summary: Grid-following storage is the grid's 'executer,' passively cooperating. Grid-forming storage is the grid's 'supporter,' proactively stabilizing the overall situation.

Part 2: In-Depth Analysis — Why Must Grid-Forming Storage be Promoted?

2.1 Core Crisis of Traditional Grids: Continuous Loss of System Inertia

Traditional thermal and hydropower units have large rotating rotors that generate enormous rotational inertia during operation — the grid's 'inertial buffer capability.'

When the grid encounters a fault or power fluctuation, the thermal generator rotor can use its own kinetic energy to instantly counteract the fluctuation, buying time for the grid to repair — stably supporting the grid. This is the grid's 'ballast stone.'

However, wind and PV are power electronics generation equipment with no rotating parts, completely lacking natural inertia.

As thermal power continues to shut down and new energy's share continues to rise, the grid's 'inertial buffer' weakens more and more. Like a ship that has removed its ballast stone, it will roll violently with the slightest wind and wave, causing large voltage and frequency fluctuations, and in severe cases triggering widespread blackouts.

2.2 Three Core Values of Grid-Forming Storage (Grid Essential Needs)

1. Fill the Grid's Short Board, Build an 'Electronic Ballast Stone'

Grid-forming storage, relying on mature VSG (Virtual Synchronous Generator) algorithm, precisely simulates the operating characteristics of traditional thermal generators, providing virtual inertia and damping support to the grid.

When grid frequency and voltage fluctuate, storage responds within milliseconds, automatically releasing or absorbing power, rapidly suppressing oscillations, and filling the fatal short board of new energy grids lacking inertia.

2. Proactively Support the Grid, Improve Anti-Risk Capability

Distinct from the passive following of grid-following storage, grid-forming storage can independently establish voltage and frequency references. In extreme scenarios such as grid faults, load surges, and new energy output fluctuations, it proactively outputs active and reactive power to stabilize the grid's condition.

It greatly improves grid fault ride-through capability and anti-disturbance capability, avoiding voltage and frequency collapse and ensuring safe and stable grid operation.

3. Support Island Operation, Build Resilient Grids

This is the unique core advantage of grid-forming storage. When the main grid faults and powers down or lines are under maintenance, grid-forming storage can seamlessly switch to off-grid island mode, independently supplying power to important loads such as hospitals, factories, and residential areas.

It completely solves power supply stability problems for remote islands, mountainous areas, and new energy power stations, and is the core supporting technology for building resilient grids and low-carbon microgrids.

Part 3: Operational Principles — How Does Grid-Forming Storage Actually Work?

3.1 Core Control Algorithms — The Storage 'Brain'

• Virtual Synchronous Generator (VSG): The mainstream core solution. Uses software algorithms to simulate the rotor operating laws of traditional synchronous generators, making the output characteristics of the storage converter essentially identical to real thermal generators. Can freely adjust virtual inertia and damping parameters, precisely replicating the voltage/frequency stabilization capability of traditional units.

• Droop Control: The foundation for multi-machine coordination. Simulates the power regulation characteristics of generator units; achieves autonomous power distribution among multiple storage devices and new energy units through a linear P-f and Q-V relationship, ensuring coordinated multi-device operation without disorder.

• Voltage Source Inner Loop Control: The core of stable operation. Grid-following storage uses current control as its core — poor stability. Grid-forming storage uses voltage control as its inner loop core — directly outputs a standard voltage waveform. It remains stable even in weak-grid and fault-grid scenarios, with far superior anti-disturbance capability over traditional storage.

3.2 Key Hardware Equipment — The Storage 'Body'

• Grid-Forming Dedicated PCS Converter: The core hardware. Must support voltage source control mode, possess high overload capability of 2-3x, withstand grid fault surges, and support multi-device parallel coordinated operation. Compared to traditional grid-following PCS, it has more complex structure, stronger stability, and higher cost.

• Battery System + EMS: The battery system must have fast power response capability, matching the PCS's regulation speed. The EMS, through upgraded dedicated algorithms, coordinates dispatch of grid-forming storage, new energy, and load, achieving optimal microgrid operation and intelligent voltage/frequency stabilization.

3.3 Four-Step Engineering Process

• Step 1: Mode Switching — Automatically or manually switches the storage PCS from the traditional grid-following PQ mode to grid-forming VSG/V-f mode.

• Step 2: Autonomous Grid Building — The PCS automatically sets standard voltage and frequency (50Hz), independently building a stable microgrid reference.

• Step 3: Inertia Empowerment — The VSG algorithm starts, injecting virtual inertia and damping into the self-built grid, endowing the grid with anti-disturbance capability.

• Step 4: Grid-Connected/Island Operation — When the grid is normal, it automatically connects and proactively supports the large grid's stability. When the grid faults, it automatically disconnects and operates in island mode. Multiple devices can operate in coordination, automatically sharing loads and building a stable, scalable microgrid.

Part 4: Complete Summary — New vs. Old Storage Comparison and Future Trends

Part 5: Final Conclusions

• Grid-following storage is the past: Adapted to the stable grids dominated by traditional thermal power. Can only do energy storage and power smoothing; cannot solve the new energy grid stability problem.

• Grid-forming storage is the future: The core technology adapted to high-ratio new energy and new power systems. Perfectly solves industry pain points: missing grid inertia, weak-grid instability, and emergency power supply during outages.

• Industry development trend: As technology iterates and costs decline, grid-forming storage will evolve from an 'optional configuration' to an 'industry standard,' becoming the core 'stabilizer' and 'ballast stone' supporting the dual-carbon goal and ensuring grid safety and stability. Mastering this technology will seize the core advantage in the new energy power track.