With the rapid development of clean energy sources like wind and photovoltaics, the power system faces a core challenge: the inability to perfectly align electricity production and consumption across time and space . Energy storage power stations, the "energy warehouses" that address this challenge, store electricity and release it when needed, effectively balancing power supply and demand and stabilizing grid operations. 

three main types based on their connection location and primary function : power-side storage, grid-side storage, and user-side storage . These three types of energy storage, each with its own specific function, collectively constitute a crucial component of the new power system.

1. Power-side energy storage: “stabilizer” and “efficiency booster”

Power-side energy storage is installed directly near power plants or renewable energy power stations (such as wind farms and photovoltaic power plants). Its primary function is to address the "capricious" nature of renewable energy generation—its volatility and intermittency . Its core role is to "smooth out fluctuations" and "enhance value . "

Smoothing out power fluctuations: When the wind is strong or the sun is bright, power generation may exceed the grid's capacity. The energy storage system promptly absorbs the excess power and releases it when the wind and sun are weak or when demand is peak. This significantly reduces wind and solar curtailment and improves clean energy utilization.

Auxiliary grid-connected operation: Provide power plants with auxiliary services such as frequency regulation and voltage regulation to meet grid-connected technical requirements and ensure stable and reliable operation of new energy power plants.

Energy time-shifting to increase efficiency: Storing electricity during periods of low electricity prices and discharging it to the grid during peak electricity price periods, creating additional economic benefits for power plants.

Grid-side Energy Storage: “Regulating Valve” and “Safety Guard”

Grid-side energy storage, independent of power plants and users, is directly connected to grid substations. It is a key tool in the hands of grid dispatchers, primarily serving the safe, stable, and efficient operation of the power system. Its core function is peak load regulation and frequency regulation.

Peak shaving and valley filling: charging during the period of low load of the overall power grid and discharging during the period of peak load, flattening the peak of the load curve and improving the utilization rate of new energy.

Frequency regulation and voltage stabilization: Rapidly responding to grid frequency fluctuations (such as large unit tripping or sudden load changes) and providing millisecond to minute frequency regulation services are key technical means to maintain grid frequency stability and ensure power quality .

Providing backup/improving resilience: It can serve as an emergency backup power source for the power grid. When a sudden failure or natural disaster causes part of the power grid to be disconnected, it can provide emergency support for important loads, thereby improving the resilience of the power grid and the reliability of power supply.

3. Behind-the-meter Energy Storage: “Smart Electric Manager” and “Money-Saving Expert”

User-side energy storage is installed at electricity-consuming terminals such as industrial and commercial enterprises, industrial parks, or residential households, directly serving users. Its core goal is to reduce electricity costs and improve power supply reliability .

Peak shaving and valley filling to reduce electricity costs: charging energy storage during off-peak electricity price periods and using the stored electricity during peak electricity price periods can significantly reduce electricity bills.

Improved power quality/reliability: For users with high power quality requirements, energy storage can provide an uninterruptible power supply (UPS) function to cope with short-term voltage sags or interruptions; it can also serve as a backup power source to provide emergency power in the event of a main power failure.

Participate in demand response: Energy storage systems can be used to participate in the grid's demand response program, reducing electricity consumption or performing reverse discharge to support the grid when needed, and obtaining additional subsidies or benefits.

Improve distributed energy efficiency: In conjunction with distributed power sources such as rooftop photovoltaics, energy storage can store excess photovoltaic power generation during the day for use at night, maximizing the proportion of self-generation and self-use and reducing electricity purchase costs.

Energy storage at the power source, grid, and user sides is like the "three horses" of the power system. They contribute to the optimization of the energy structure and the intelligentization of the power system, respectively, at the source of power generation, the central grid, and the end user. With technological advancements and cost reductions, the application of these three types of energy storage will become more widespread, providing solid support for building a clean, safe, and efficient new power system.