What is energy storage?

With the proposal of the dual carbon goals, accelerating the development of renewable energy has become a key task for the development of China’s energy industry. During the 14th Five-Year Plan period, China will continue to uphold market dominance and policy-driven momentum, emphasize overall planning and diversified development, encourage innovative demonstration and pilot trials, and advance the large-scale, industrialized and market-oriented development of new energy storage.

With the implementation of national policies and enforcement by local governments, the proportion of new energy power generation has increased year by year, triggering explosive growth in the energy storage market. At home and abroad, demonstration projects for various types of energy storage construction have been launched one after another, driving the advancement of energy storage technologies.

Energy storage refers to the process of storing energy via media or equipment and releasing it when needed. It is an urgent necessity to address the intermittency and instability of renewable energy, as well as improve the efficiency, safety and economic efficiency of conventional power systems and regional energy systems. Energy storage can smooth the output fluctuation of renewable energy, enable dispatchable power output, and support peak regulation and frequency regulation. It enables stable and controllable power output from renewable energy generation, meets the requirements for large-scale grid connection of renewable energy power, and is of great significance for building a new power system dominated by clean energy and achieving the goals of carbon peaking and carbon neutrality.

China’s domestic energy storage market is developing rapidly with a constant stream of new technologies, jointly fueling the sustained growth of the energy storage industry. High-voltage cascaded energy storage boasts prominent advantages in large-capacity scenarios. New electrochemical energy storage technologies are developing rapidly, with the industrialization of sodium-ion battery energy storage, flow battery energy storage, hydrogen energy storage and other types accelerating steadily. New physical energy storage technologies are emerging in an endless stream, and demonstration projects such as solar thermal energy storage, compressed air energy storage and flywheel energy storage are being gradually implemented.

Electrochemical Energy Storage

Electrochemical energy storage refers to technologies and measures that store electric energy through chemical batteries and release it on demand. The global electrochemical energy storage market is mainly divided into five application scenarios: new energy plus energy storage, power supply side auxiliary services, grid-side energy storage, distributed energy storage and microgrids, as well as peak shaving and valley filling on the user side.

Lithium-ion Battery Energy Storage

Lithium iron phosphate is the mainstream material system for lithium battery energy storage, and batteries are continuously evolving toward larger capacity. As required by the Ministry of Industry and Information Technology, the energy density of energy storage batteries shall be no less than 145Wh/kg, and that of battery packs no less than 110Wh/kg. The cycle life shall be no less than 5,000 times with a capacity retention rate of no less than 80%.

Current electrochemical energy storage, especially lithium battery energy storage technology, has entered a new transformation cycle. New products and technologies such as large-capacity cells, high-voltage design, water cooling and liquid cooling are gradually being applied, and energy storage systems keep evolving toward larger capacity.

In 2022, the annual shipment of energy storage lithium batteries reached 130GWh, a year-on-year increase of 170.8%, outpacing the growth rate of power batteries. In segmented tracks, the shipments of power energy storage, residential energy storage and portable energy storage batteries all climbed. Among them, residential energy storage saw the fastest growth with a year-on-year increase of over 3.5 times, while power energy storage and portable energy storage both grew by more than twice. By contrast, the shipment of communication energy storage batteries slowed down, posting a year-on-year decline of 25% in 2022.

Sodium-ion Battery Energy Storage

Compared with lithium resources, sodium resources are extremely abundant, leaving sodium batteries free from prominent resource constraints in large-scale application scenarios. In addition, the theoretical cost of cathode materials and current collector materials for sodium batteries is lower than that of lithium batteries. After industrial cost reduction, its initial investment cost is expected to be 40%-50% lower than that of lithium batteries while delivering 70% of lithium batteries’ performance, making it suitable for markets with low energy density requirements such as energy storage.

Technical Characteristics: Low cost, high safety, good high and low temperature performance; relatively low energy density and short cycle life.

Development and Application: Mainly applied to standby power supplies, electric two-wheelers and tricycles, peak and frequency regulation of power systems, communication base stations, etc.

Key Technologies: New electrode materials, high-rate hard carbon, electrolytes with high electrochemical stability voltage, dry electrode technology, etc.

The above content is sourced from online materials.