Electrochemical energy storage power stations may appear to consist of several prefabricated modules, but do you really understand them? What are their components? What are the equipment costs and investment amounts? How is the unit price calculated? Let's look at a project example. This is a 100MW/200MWh electrochemical energy storage power station in Shandong.

Actually, "W" represents power output. 100MW corresponds to the PCS booster module in the red box in the diagram, and "Wh" represents electrical energy. 200MWMh represents the battery module in the green box. 100MW/200MWh means that 200MWh of electrical energy is converted from DC to AC by a 100MW energy storage converter (PCS). It takes 2 hours to discharge all the electricity, which is called 0.5C in industry terms. Discharging for 4 hours is 0.25C, and discharging for 1 hour is 1C. This is the conventional "low-voltage energy storage + boost" solution. When calculating the unit price of an energy storage project, you typically only need to divide the total cost by the battery capacity, i.e., the number displayed before the unit "MWh". During the conversion, it's crucial to maintain unit consistency; it's usually calculated in "yuan/Wh".

For example, the unit price quoted by the first-ranked bidder for this project = 125,442,000 yuan ÷ 80,000,000 W ≈ 1.568 (yuan/Wh).

So what does the "4S" of an electrochemical energy storage power station refer to? Below is a simplified structural diagram of an energy storage battery system. As you can see, the energy storage battery pack, battery management system (BMS), bidirectional converter (PCS), and energy management system (EMS) together constitute the energy storage battery system. Additionally, for large-capacity energy storage power stations, to achieve millisecond-level response times, a storage coordination controller (PMS) is also required.

BMS, PCS, PMS, and EMS, abbreviated as "4S," together form the core of an electrochemical energy storage system. Let's examine each component individually. The Battery Management System (BMS) acts as the battery's caretaker, constantly monitoring its status to ensure safe operation. The Bidirectional Converter System (PCS), as mentioned above, converts DC to AC to meet the power demands and energy service requirements of energy storage. The Power Management System (PMS) enables large-capacity power plants to achieve fast and precise power control. The Energy Management System (EMS) is the brain of the energy storage system, responsible for crucial tasks such as automatic power generation control, economic regulation, and safety analysis.

Regarding equipment and investment costs, according to data from GGII (Gaogong Lithium Battery Research Institute), in a complete electrochemical energy storage system, the battery pack accounts for the highest cost (67%), by the PCS at 10%, with the BMS and EMS accounting for 9% and 2% respectively. Clearly, battery pack cost remains the primary cost component of electrochemical energy storage systems and represents a key area for future technological iteration and cost reduction across the industry chain. When calculating the investment cost of a 100MW/200MWh energy storage power station, it can be roughly divided into two parts: the battery compartment and the booster compartment. The battery compartment is generally a 40-foot container, which houses the batteries and BMS, and is also equipped with a temperature control system and a fire protection system. We calculate it at 0.45 yuan/Wh, so 200MW would cost 0.9 billion yuan. The remaining part is included in the booster compartment, calculated at 0.5 yuan/W, so 100MW would cost 0.5 billion yuan. Therefore, the total equipment cost of this 100MW/200MW energy storage power station is about 1.4 billion yuan.