The energy storage time, maximum storage capacity, and excess energy storage method of an energy storage power station mainly depend on the type of energy storage technology, the design specifications of the power station, and specific application requirements. The following are examples of several common energy storage technologies and their electrical energy storage characteristics:
1、Types and characteristics of energy storage technology
1. Battery energy storage (such as lithium-ion batteries, lead-acid batteries, etc.)
Energy storage time: Due to the influence of battery charging and discharging efficiency, self discharge rate, and maintenance status, the storage time is generally short. High performance battery systems may achieve longer storage time through special design.
Maximum storage capacity: The storage capacity of a single battery unit is limited, but by combining them into large-scale battery modules (battery series parallel), it can reach tens of kilowatt hours to hundreds of megawatt hours (MWh), thus meeting higher energy storage needs.
Storage of excess electricity: When there is excess electricity in the power grid, it is converted into chemical energy stored in batteries through a charging system; When electricity is needed, the energy stored in the battery is fed back to the grid through devices such as energy storage inverters.
2. Pumped storage
Energy storage time: In theory, it can be stored for a long time as long as the water volume of dams and reservoirs is sufficient, and the process of pumping and releasing water does not have a negative impact on the ecology.
Maximum storage capacity: The storage capacity depends on the volume of the reservoir and the power of the pumping units, typically ranging from one million kilowatt hours (MWh) to gigawatt hours (GWh), which makes it an important player in large-scale energy storage.
Storage of excess electricity: When electricity exceeds demand in the power system, an electric motor is used to drive a water pump to pump water from the bottom to a higher reservoir; When the demand for electricity increases, water is released through water turbines to generate electricity and supply it back to the grid.
3. Compressed air energy storage
Energy storage time: Theoretically, it can be stored for a long time, but it is limited by the capacity of the gas chamber and the stability of the compressed air.
Maximum storage capacity: determined by the size of the chamber and the power of the compressor unit, it can store considerable electrical energy, but its scale may be slightly smaller compared to pumped storage.
Storage of excess electricity: Use excess electricity to drive a compressor and store compressed air in a high-pressure container; When electricity is needed, compressed air is released through a turbine and converted into electrical energy.
4. Flywheel energy storage
Energy storage time: usually short, ranging from a few minutes to several hours, suitable for quickly responding to power regulation needs.
Maximum storage capacity: Due to factors such as the physical size, material, and rotational speed of the flywheel, the storage capacity is relatively small and suitable for frequent charging and discharging situations.
Storage of excess electricity: Transfer excess electrical energy to the flywheel through a motor, causing it to rotate at high speed and convert electrical energy into mechanical energy for storage; When electrical energy is needed, the flywheel decelerates and converts mechanical energy back into electrical energy through a generator.

2、 Specific operational points

Different types of energy storage power stations have slightly different operating methods, but generally include monitoring the status of energy storage equipment, controlling the charging and discharging process, optimizing the operational efficiency of the system, and necessary maintenance. In the context of smart grids, energy storage stations are usually connected to grid dispatch systems to monitor grid demand and electricity price changes in real time, automatically or manually adjust energy storage strategies to achieve efficient allocation and dispatch of electrical energy. Through such management, energy storage stations can play an important role in balancing electricity supply and demand, improving grid stability, and other aspects.