New Energy Storage-Flywheel Energy Storage Industry Status

Flywheel energy storage, a kind of physical energy storage, is a kind of energy storage that uses electric motor to drive the flywheel to rotate at high speed in vacuum, and drives the generator to generate electricity through the inertia of the flywheel when needed, which has the advantages of fast response speed, good power characteristics, long service life, and so on.

Composition of flywheel energy storage

Flywheel energy storage system mainly consists of rotor system, support system, motor energy storage converter three parts.

Rotor system is the basic structure of the flywheel energy storage system, according to the composition of different materials can be divided into composite materials and steel flywheel.

When the flywheel rotation speed is low (about 10.000 revolutions per minute), the general use of steel flywheel, can effectively improve the safety and stability of the rotor operation, China's power grid energy storage flywheel products are mainly used in steel flywheel.

When the rotation speed is higher (100.000 revolutions per minute), the use of lighter quality but strong composite materials, the cost is much higher than the steel flywheel.

The support system can be divided into mechanical bearings, permanent magnetic bearings and electromagnetic bearings, which can support the rotor rotation, reduce friction resistance, and run the whole device with minimum loss. At present, China's mechanical bearing technology is gradually mature, is currently the most widely used way.

There is a built-in motor in the flywheel energy storage system, which can regulate the two states of charging and discharging, and the motor energy storage converter is needed to realise the function of grid frequency regulation. When charging, the electrical energy is converted into mechanical energy, and when discharging, the mechanical energy is converted into electrical energy and the frequency is converted into the grid frequency, so that the AC power can be input into the grid system in time to achieve the function of frequency regulation.

In addition, vacuum and cooling are also important components in the flywheel energy storage system. Usually, the higher the electric power of the flywheel energy storage system, the greater the cooling needs, and if the cooling is insufficient, the temperature of the flywheel will be too high, which will lead to the damage of the machine. Therefore, heat sinks are usually installed on the flywheel housing to increase the heat dissipation area and ensure the effective operation of the system.

Application Scenarios

According to the advantages of flywheel energy storage such as fast response, high power, small footprint, long life, etc., it is generally used in many scenarios such as uninterruptible power supply (UPS), rail transport, car battery, grid frequency regulation, grid peaking and so on.

Uninterruptible power supply: When the power grid fluctuations, instantaneous breaks, intermittent and other problems, flywheel energy storage can instantly provide emergency power supply, while flywheel energy storage can be continuous and rapid depth charging and discharging, which can not be replaced by electrochemical energy storage.

Rail transport: in August 2021. China's first megawatt-class flywheel energy storage device as a railway traction substation put into use in Hebei, when the train into the station brakes produce huge electrical energy for the flywheel energy storage system charging; when the train speed out of the station, the flywheel in the kinetic energy released to the train.

Car batteries: Early had a completely flywheel-driven buses, in addition, a variety of Porsche racing car has also been applied to flywheel energy storage, and achieved good results in the race, but because of its low capacity of the battery, low cost-effective reasons, not applicable to the mileage of the car, but it is in the performance indicators, safety are applicable to the car in the future if you can improve its energy density, it will be very potential for development.

Grid peak frequency regulation: due to the wind power photovoltaic and other energy sources of volatility, and grid power generation and power imbalance, so the need to join the grid in the peak frequency regulation power plant, at present, China's energy storage is mainly pumped hydroelectric storage, followed by electrochemical energy storage, flywheel energy storage, small size, high power, non-polluting and so on, in the power grid has a very promising prospects for the application of the flywheel storage has been a number of foreign organisations will flywheel storage access to the wind power generation system. system.