In recent years, with the continuous increase in the proportion of renewable energy. The randomness, intermittency, and volatility of new energy power generation seriously affect the stability of the power grid, and its own lack of frequency regulation capability has become a major obstacle restricting its further expansion. How to use these green and low-carbon new energy power more safely, stably and economically has become a challenge for the new power system.
Energy storage, using special devices and systems to store energy, release energy when needed, and realize energy transfer in time and (or) space. It has the characteristics of fast frequency modulation and adjustable capacity, providing guarantee for the stable operation of the power grid . Based on this, energy storage is considered to be an essential part of building a new power system with new energy as the main body.
flywheel energy storage
Energy storage is divided into physical energy storage, electrochemical energy storage, and electromagnetic energy storage. Flywheel energy storage is a kind of physical energy storage. The working principle of flywheel energy storage: under the condition of surplus power, the flywheel is driven by electric energy to rotate at a high speed, and the electric energy is converted into mechanical energy for storage; when the system needs it, the flywheel decelerates, and the motor operates as a generator to convert the kinetic energy of the flywheel into electric energy for the user use. Flywheel energy storage realizes the storage and release of electric energy through the acceleration and deceleration of the rotor.
When charging, the speed increases; when discharging, the speed decreases.
Compared with other energy storage modes, flywheel energy storage has the characteristics of long service life, multiple charging times, high energy density, and good safety and environmental performance.
Composite frequency modulation: flywheel energy storage + lithium battery energy storage
Through the “perfect combination” of flywheel and lithium battery energy storage, it combines the advantages of flywheel energy storage with large instantaneous power, millisecond response, multiple charge and discharge times, lithium battery energy storage capacity and high frequency modulation range, and cooperates with thermal power units to assist frequency modulation. It can solve the impact of frequency disturbance on grid stability.
For the first time, the flywheel energy storage compound frequency modulation project combines the advantages of “long life” of flywheel energy storage device and “large storage capacity” of lithium battery, which not only expands the total capacity of the system, but also improves the durability of the battery. Combined with the existing thermal power units to provide frequency regulation services for the power grid, it can effectively meet the frequency stability of the power system, and at the same time can effectively balance the problem of the power difference between the power generation of thermal power units and the power consumption required by grid dispatching.
This design makes the number of charging and discharging times 2,000 times higher than that of pure lithium battery systems, and can save about 24 million yuan in replacement costs for 3 batches of lithium battery packs within the same life cycle.
Power System Form
Three elements from source network to load
Transformation to the four elements of source, network, load and storage
The role of energy storage is becoming more and more prominent
Has a wider application prospect
As flywheel energy storage technology matures and costs decrease
More flywheel energy storage application projects will be implemented
Provide support for greener, more stable and safer urban electricity consumption