【Major Industrial Equipment in the Chemical Engineering Sector】509 – Metro photovoltaic power generation + flywheel energy storage system from 2022

Flywheel energy storage breaks monopolies and reduces traction energy consumption by 15%. The subway is itself a green, low-carbon, and environmentally friendly mode of transportation, tasked with helping to reduce carbon emissions. Urban rail transit stations are spaced closely together, and trains start and stop frequently; therefore, they can be considered to be major consumers of electricity during operation. A considerable amount of energy is generated by trains during braking (what people commonly refer to as \"braking\"), and this energy can be reused. At present, existing energy-saving technologies and products are insufficient to meet the industry’s needs for energy conservation and carbon reduction in the new circumstances, making the development of low-carbon technologies an essential step that cannot be bypassed. According to statistics, the energy generated by the braking of rail transit trains can account for 20%-40% of the energy consumed by the traction system; if this energy is made full use of, it can significantly reduce the operational energy consumption of rail transit. The flywheel energy storage system on Qingdao Metro Line 3 is the first megawatt-class flywheel energy storage device in China’s rail transit industry to possess fully independent intellectual property rights. Flywheel energy storage belongs to physical energy storage; it utilizes magnetic levitation technology, with the flywheel rotor operating inside a vacuum chamber in an environment free from air resistance. The flywheel energy storage device is installed in the traction substation of rail transit systems. When a train brakes as it enters the station, the flywheel absorbs energy and converts electrical energy into kinetic energy, with a rotation speed of up to 20,000 revolutions per minute ； When the train accelerates as it leaves the station, the flywheel releases energy, converting kinetic energy into electrical energy that can be used by the train, thereby providing excellent energy-saving and voltage-stabilization effects.

New Energy Expansion Series, placed within this series

As a storage technology with high power density, high reliability, long lifespan, and environmental friendliness, flywheel energy storage offers significant advantages over medium-voltage inverter and capacitor-based storage technologies. However, flywheel energy storage technology is relatively complex and has long been monopolized by foreign countries. China has made numerous attempts in this field, but it is still in the stage of technology development and testing, and has not yet been put into widespread use. In 2021, the **National Development and Reform Commission issued the \"Guiding Opinions on Accelerating the Development of New Energy Storage,\" which called for accelerating large-scale testing and demonstration of technologies such as flywheel energy storage and sodium-ion batteries.** In line with the industry’s needs, Qingdao Metro has entered into a strategic partnership with Hubei East Lake Laboratory. By leveraging the strengths of all parties involved in the \"industry-academia-research-application\" ecosystem, they are working together on research and development in areas related to energy savings and carbon reduction in rail transportation, with focus on technologies such as flywheel energy storage, in order to break foreign technological monopolies. Once the two flywheel energy storage units are put into use, it is estimated that they will save approximately 500,000 kWh of electricity per year; over a 30-year lifespan, this will result in a savings of 15 million kWh, leading to cost savings of around 10.65 million yuan. At the same time, its voltage fluctuation suppression function can significantly improve the stability of the traction power supply system for rail transportation and enhance the power quality of the supply system. Qingdao Metro is actively collaborating with research institutions such as Hubei East Lake Laboratory to promote the use of flywheel energy storage systems. This approach can result in a 15% reduction in traction energy consumption; the entire transit network can save 50 million kWh of electricity per year, thereby reducing carbon dioxide emissions by around 50,000 tons per year. In the future, once Qingdao Metro fully adopts solutions such as \"flywheel + inverter\" composite energy storage and permanent magnet traction, it will be possible to reduce traction energy consumption by over 30%. This will play a significant role in facilitating the green transformation of Qingdao Metro and the entire rail transit industry, contributing to the achievement of the **\"dual carbon\" strategic goals.