Energy storage plays a crucial role in the entire electricity value chain, impacting generation, transmission, distribution, and even end-user electricity consumption. By buffering electricity through energy storage systems, power quality can be optimized and the stability of renewable energy microgrids can be improved. So, what role do energy storage systems play in microgrids? Let's find out in the following article.
Microgrids are an important component of smart grids. They enable integrated operation of internal power sources and loads, and can coordinate and control with the main grid. They can be smoothly connected to the main grid or operate independently, and can meet or even improve users' requirements for power quality, power reliability and security.
The main roles of energy storage systems in microgrids are as follows:
I. Improve the stability of distributed energy resources
Distributed energy sources, such as solar, wind, and biomass energy, are generally greatly affected by external environmental factors such as sunlight, temperature, wind speed, and climate, resulting in random and unstable power generation. Energy storage systems, applied in microgrids, utilize an energy management system (EMS) to coordinate the control of distributed energy sources with the main grid. This can smooth out fluctuations in distributed energy output, ensure stable output, and improve the local utilization rate of distributed energy, avoiding transmission pressure and power loss caused by long-distance transmission to the main grid.
In addition, energy storage systems can continue to provide partial power to major loads at night or during distributed energy maintenance, reducing power outage time.
II. Improve the power quality for users' electricity consumption.
When a microgrid is connected to the main grid and operates in grid-connected mode, its power quality must meet relevant national standards, meaning that parameters such as power factor, voltage asymmetry, current harmonic distortion rate, and voltage sag must reach the corresponding values.
As mentioned in point one above, without energy storage systems, microgrids cannot guarantee power quality, especially voltage stability, due to the inherent characteristics of their energy sources. The use of energy storage systems plays a crucial role in improving the power quality of microgrids. By controlling the PCS within the energy storage system, the system stabilizes power output while regulating the active and reactive power output from the energy storage system to the microgrid, and simultaneously addresses voltage dips/sags.
When faced with sudden voltage spikes and drops in the main grid, energy storage systems can provide rapid power buffering, quickly absorb/replenish electrical energy, provide active and reactive power support, and stabilize voltage fluctuations. Energy storage systems can also provide some harmonic mitigation capabilities for microgrids.
III. Peak Shaving
In microgrids, energy storage systems can store excess electricity generated by distributed energy sources during off-peak hours and release it during peak hours to regulate load demand. As an energy buffer within the microgrid, energy storage systems are indispensable.
