Abstract: The development and utilization of renewable energy represent a pivotal direction for China’s future energy structure transformation. However, renewable energy generation is characterized by volatility, intermittency, and randomness, posing challenges to the safe and stable operation of the power system. Energy storage technology, as a crucial technology to ensure the safe and stable operation of the power system, plays a significant role in promoting the development of renewable energy and the coordinated development of the power grid. This article first analyzes the role of energy storage technology in promoting the coordinated development of renewable energy and the power grid. It then discusses the issues related to energy storage in this context and proposes application strategies to promote energy storage from multiple perspectives.
Keywords: renewable energy; power grid; coordinated development; energy storage system; efficiency
1. Introduction
With the rapid economic development of China, the renewable energy industry, particularly wind and solar energy, has seen rapid growth. The dependency of China’s power system on renewable energy is increasingly strong. However, the output of wind and solar energy is highly volatile and intermittent, directly affecting the stability of the power grid. Energy storage technology, as a novel regulation means for power systems, can effectively mitigate the impact of renewable energy output fluctuations on grid stability. Therefore, strengthening research on the role of energy storage technology in the coordinated development of renewable energy and the power grid is of great significance.
2. The Role of Energy Storage System in the Coordinated Development of Renewable Energy and Power Grid
2.1 Balancing Grid Supply and Demand and Enhancing Grid Stability
The large-scale integration of renewable energy, especially wind and solar energy, into the power grid has made the instability of their output a non-negligible issue. The output of wind and solar energy is influenced by various external factors, such as climate change, weather conditions, and seasonal variations. This means that during certain periods, the power supply from renewable energy may far exceed grid demand, while during others, it may be significantly lower than demand. This supply-demand imbalance poses a serious threat to grid stability, leading to power interruptions, voltage fluctuations, and other issues.
To address this problem, energy storage systems (ESSs) have emerged. energy storage systems, such as battery energy storage, pumped hydro storage, and compressed air energy storage, can store excess energy generated by renewable sources when output is high and release this stored energy when output is low. This effectively balances supply and demand in the grid. In this way, even when the wind is not blowing or the sun is not shining, power supply to the grid remains stable, avoiding power shortages. energy storage systems can also effectively respond to instantaneous demand fluctuations in the grid. For example, during large events or emergencies, grid demand may suddenly increase. At this time, energy storage systems can quickly release stored energy to meet the instantaneous demand of the grid, preventing voltage collapses or power interruptions.
| Aspect | Description | Impact |
|---|---|---|
| Supply-Demand Balancing | Stores excess energy and releases it during短缺 periods | Stable power supply |
| Instantaneous Demand Response | Quickly releases stored energy during sudden demand spikes | Avoids voltage fluctuations and power interruptions |
2.2 Providing Rapid Frequency Regulation and Emergency Backup Energy
In the coordinated development of renewable energy and the power grid, energy storage systems play a vital role in providing rapid frequency regulation and emergency backup energy. The operation of the power grid requires maintaining a specific frequency level to ensure stable power supply and avoid damage to electrical equipment. However, there are continuous dynamic changes between grid load and power production. In specific situations, such as when large generators suddenly go offline or grid load instantaneously changes due to emergencies, the grid frequency may deviate rapidly from its normal range.
At this time, energy storage systems, with their high-response speed characteristics, can quickly inject or absorb electrical energy from the grid to maintain the grid frequency within the specified range. Lithium-ion batteries and flywheel energy storage, for example, have been widely used in this regard due to their excellent response speed and frequency regulation capabilities. Furthermore, when the grid faces sudden power interruptions, such as the sudden failure of traditional power generation units or power outages caused by severe weather events, energy storage systems can quickly serve as emergency backup energy. Compared to traditional thermal generators, energy storage systems can start and provide electrical energy to the grid within seconds, significantly reducing the time required for the grid to return to normal operation.
| Function | Technology | Impact |
|---|---|---|
| Frequency Regulation | Lithium-ion batteries, flywheel energy storage | Maintains grid frequency within normal range |
| Emergency Backup | Various energy storage systems | Provides immediate power during outages, reduces recovery time |
2.3 Facilitating the Integration of Distributed Energy Resources
In the coordinated development of renewable energy and the power grid, energy storage systems play a crucial role in facilitating the integration of distributed energy resources (DERs). In traditional centralized power systems, electrical energy production and transmission primarily rely on large power stations and cross-regional transmission networks. However, modern power systems are gradually shifting to a DER model, which means a large number of small, decentralized generation units such as solar panels, wind turbines, and microturbines are integrated into the grid. These DERs are highly flexible and localized, allowing power generation close to load points, thereby reducing transmission losses and increasing grid resilience.
Firstly, energy storage systems provide load balancing functionality for DERs. When DER output exceeds load demand, excess electrical energy can be stored and released when load increases or DER output decreases. This allows DERs to more flexibly adapt to grid demand changes, improving their operational efficiency. Secondly, energy storage systems provide voltage support and power quality management functions for DERs. During the integration of distributed power sources into the grid, the grid’s voltage and frequency may be affected. Through advanced control strategies, ESSs can adjust the discharge or charge of electrical energy in real-time, ensuring that the grid’s voltage and frequency remain within appropriate ranges. Finally, when combined with advanced grid management systems and cloud platforms, energy storage systems can achieve remote control and optimization, making DER management more intelligent and automated.
| DER Integration Aspect | Energy Storage System Function | Impact |
|---|---|---|
| Load Balancing | Stores excess energy, releases during high demand | Improves DER operational efficiency |
| Voltage Support | Real-time adjustment of energy flow | Maintains grid voltage and frequency stability |
| Power Quality Management | Regulates power flow to maintain quality | Ensures stable power supply to DERs |
3. Issues Related to Energy Storage System in the Coordinated Development of Renewable Energy and Power Grid
3.1 Capacity Degradation Due to Battery Technology Limitations
In the coordinated development of renewable energy and the power grid, energy storage systems play a crucial role, but the core of energy storage systems—battery technology—still has significant limitations, with capacity degradation being particularly prominent. Lithium-ion batteries, as the most mainstream energy storage method currently, face the dilemma of gradually decreasing capacity with cumulative charging and discharging cycles. The root of this degradation mainly stems from changes in the chemical reactions within the battery.
Firstly, as the usage cycle increases, the process of lithium-ion insertion and extraction in the battery’s anode and cathode materials can cause the microstructure of the electrode materials to gradually change, potentially even producing cracks, thereby reducing the battery’s energy storage capacity. Secondly, the solid electrolyte interphase (SEI) layer, which plays a crucial role in lithium-ion movement, can also be damaged, affecting its stability. The stability of this interface is not only related to battery life but also to battery safety. Thirdly, incomplete lithium-ion circuits during battery charging and discharging can lead to the accumulation of lithium, forming so-called “lithium dendrites.” These dendrites may pierce the battery separator, causing short circuits, seriously affecting battery safety and service life. These microscopic physicochemical changes ultimately manifest as battery capacity degradation on a macroscopic scale. Fourthly, overheating of the battery during charging and discharging may also lead to the degradation of battery materials, thereby accelerating capacity degradation.
| Cause of Capacity Degradation | Description | Impact |
|---|---|---|
| Microstructural Changes | Changes in electrode materials | Reduced energy storage capacity |
| SEI Layer Damage | Damage to the interface crucial for lithium-ion movement | Affects battery life and safety |
| Lithium Dendrite Formation | Accumulation of lithium during charging and discharging | Causes short circuits, reducing safety and lifespan |
| Overheating | High temperatures during charging and discharging | Accelerates material degradation, reducing capacity |
3.2 High Investment Costs Resulting in Low Economic Benefits of Energy Storage
The coordinated development of renewable energy and the power grid increasingly relies on energy storage technology. However, the popularization and application of energy storage face a significant challenge in practice: the economic benefits issue arising from high investment costs. Firstly, the current research and development (R&D) and production of energy storage systems require substantial initial investments. From raw material procurement, battery and other key component production, to system integration and installation, each stage involves significant capital expenditures. Especially for high-performance materials and advanced processes, although they have significant technical advantages, their costs are relatively high, further driving up the overall investment budget. Secondly, the operation and maintenance costs of energy storage projects cannot be ignored. To ensure the stable operation of the system, regular inspections, updates of some components, and even technological upgrades are required, which will increase ongoing operational expenses.