What special requirements does power generation-side energy storage impose on energy storage batteries?

Writer： admin Time：2025-12-06 14:32:35 Browse：8℃

Energy Storage for Power Generation: Key Requirements and Challenges

Energy storage for power generation is a critical support system for integrating renewable energy (such as wind and solar power), optimizing grid peak shaving and frequency regulation, and enhancing the stability of the power system. The application scenarios (such as long-term grid connection, extreme operating conditions, and frequent charge/discharge cycles) differ significantly from those of power batteries and user-side energy storage systems. Therefore, energy storage batteries for power generation must meet five core requirements: long lifespan, high safety, wide operational adaptability, low cost, and high consistency. These requirements are explained in detail below:

1. Long Lifespan: Matching the Power Generation Asset Lifespan and Reducing Replacement Costs

Energy storage systems for power generation projects (such as photovoltaic power plants and wind farms) generally have an operational life of 20 to 25 years. Since the energy storage system is a core supporting facility, it needs to align with the lifespan of the power generation assets to avoid frequent battery replacements, which can lead to escalating costs. This imposes strict requirements on the battery's "cycle life" and "calendar life":

• Cycle Life: It should support over 10,000 deep charge/discharge cycles (national standards require ≥3,000 cycles, but power generation side needs more than 3 times that), with a capacity retention rate of ≥80% after cycling. For example, a photovoltaic storage system typically undergoes one charge/discharge cycle per day (discharging during the day and charging at night). 10,000 cycles can cover nearly 28 years of use, matching the entire lifecycle of the power station.

• Calendar Life: Even during idle periods (such as when grid load is low and no energy storage is required), the battery should have good resistance to degradation. It must maintain a capacity loss of ≤20% after 10 years of calendar life under standard storage conditions (25°C).

• Comparison: Power batteries typically have a cycle life of 2,000 to 3,000 cycles (suitable for vehicle use for 5-8 years), which is far from meeting the long-term operational needs of power generation.

2. High Safety: Addressing Long-Term Grid Connection and Complex Environments to Avoid Systemic Risks

Energy storage for power generation typically exists in the form of "large-scale energy storage stations" (with capacities ranging from tens of MWh to GWh). The batteries are grouped on a large scale and are concentrated, so if thermal runaway occurs, it can cause a "chain reaction" (such as fires or explosions), resulting in significant economic losses and grid accidents. Therefore, safety requirements are much higher than for distributed energy storage systems:

• Heat Runaway Resistance: The batteries must pass more stringent safety tests, such as "puncture, compression, and thermal shock" tests (some standards even require 85°C cycling without issues), and must have self-healing and self-shutdown capabilities (e.g., using ceramic-coated separators and flame-retardant electrolytes) to prevent a single cell failure from spreading to the entire group.

• Long-Term Stability: The batteries must withstand "long-term full-power charge/discharge" and "high SOC (state of charge) static storage" (for example, during excess solar output at noon, the battery may be at over 90% SOC for a long period). This ensures that issues such as electrolyte decomposition and positive electrode material collapse do not pose safety risks.

• Extreme Environmental Adaptability: Some energy storage stations are located in high-altitude areas (such as Qinghai and Xinjiang photovoltaic bases), hot climates (southern regions), or cold climates (northern winter). The batteries need to maintain safety performance in a wide temperature range of -30°C to 60°C, avoiding dendrite formation at low temperatures (to prevent short circuits) and thermal runaway at high temperatures.

3. Wide Operational Adaptability: Matching the Fluctuations of Renewable Energy Generation and Grid Scheduling Needs

The core task of energy storage for power generation is to "smooth the fluctuations of renewable energy output" (e.g., sudden increases in solar output during the day or fluctuating wind energy at night) and "respond to grid peak shaving and frequency regulation instructions" (e.g., rapidly discharging during high grid load and charging during low grid load). This requires the battery to stabilize output under complex operating conditions:

• Flexible Charge/Discharge Rate: The battery needs to support both "low rate long-time charge/discharge" (such as smoothing out daily fluctuations in solar energy with 0.5C-1C cycles) and "high rate short-time response" (such as rapid charge/discharge for grid frequency regulation with 2C-5C rates). The battery should also exhibit minimal capacity loss and controllable heat generation during rate switching.

• Wide SOC Range Operational Capability: Regular energy storage batteries typically operate within the 20%-80% SOC range. However, for power generation, the battery often operates within a wide SOC range of 10%-90% or even 5%-95% (for example, in extreme weather conditions, the battery may need to "fully charge and discharge" to ensure power supply). The battery should be resistant to dendrite formation at low SOC and structural collapse at high SOC, ensuring extended life.

• Resistance to Fluctuations: Renewable energy generation (e.g., wind) is intermittent and volatile, which can lead to frequent charge/discharge current fluctuations (e.g., the current may fluctuate from 1C to 3C and then drop back to 1C within 10 seconds). The battery should have good "dynamic response ability" to avoid increased polarization and risks of thermal runaway caused by current fluctuations.

4. Low Cost: Adapting to the Low-Return Characteristics of Power Generation and Ensuring Project Economic Feasibility

The revenue of energy storage for power generation mainly comes from "new energy consumption subsidies" and "peak shaving and frequency regulation service fees." The overall revenue is lower than that of user-side energy storage (such as peak-valley arbitrage). Therefore, "cost reduction" is essential for the commercialization of energy storage for power generation, and the specific cost requirements for batteries include:

• Unit Energy Cost ($/kWh): The target cost of energy storage batteries for power generation should be below 0.5 yuan/Wh (about 70 USD/kWh) to ensure that the storage project achieves an internal rate of return (IRR) above 8% (the industry profit threshold). This requires reducing costs in materials (e.g., replacing ternary lithium with lithium iron phosphate and using cobalt-free cathodes) and processes (e.g., integrating cells and simplifying grouping structures).

• Lifetime Cost (LCOE): The total cost over the battery's lifecycle, including battery life and maintenance costs, must be considered. For instance, a battery with a cycle life of 15,000 times may have a slightly higher initial cost (e.g., 0.55 yuan/Wh), but its lifetime cost (LCOE) may be lower than that of a battery with 5,000 cycles and an initial cost of 0.45 yuan/Wh (because frequent replacements are not needed), making it more suitable for the long-term economic needs of power generation.

5. High Consistency: Ensuring Large-Scale System Stability and Reducing Maintenance Difficulty

Energy storage systems for power generation consist of thousands or even millions of cells connected in series or parallel (e.g., a 100MWh station requires about 2 million 280Ah cells). The "consistency" of these cells (in terms of capacity, voltage, internal resistance, and rate of degradation) directly affects the overall performance of the system:

• Initial Consistency: The cells must be strictly screened during manufacturing, with capacity deviation ≤2%, voltage deviation ≤5mV, and internal resistance deviation ≤10mΩ to avoid the "weakest link" effect (where one cell degrades rapidly, causing the whole system to fail prematurely).

• Long-Term Consistency: During the 20-year operational cycle, the rate of degradation between cells must remain consistent (with an annual degradation rate difference ≤1%), to prevent certain cells from entering a "failure state" early and causing imbalances in charge/discharge, which increases operational costs (such as replacing individual cells).