Can "moving bricks" still store energy? Gravity energy storage relies on "moving bricks" to consume and utilize renewable energy on a large scale

Can "moving bricks" still store energy? A few days ago, the reporter learned from China Tianying that the company is in the process of digesting, introducing and re-innovating the second-generation gravity energy storage technology EVx, and will build the world's first 100MWh gravity energy storage demonstration project in Rudong, Jiangsu.

After the introduction of the "14th Five-Year Plan for New Energy Storage Development Implementation Plan", many energy storage methods have become known. In addition to traditional pumped storage, there are also rapidly developing electrochemical energy storage, as well as compressed air energy storage and hydrogen storage. Can wait.

In recent days, affected by the news of the rapid growth of the global energy storage market, the A-share energy storage sector has continued to strengthen. The project construction, scenario application, and commercial operation of energy storage have become the focus of the industry. Compared with other energy storage methods, what are the advantages of gravity energy storage?

Gravity energy storage relies on "moving bricks"

Gravity energy storage is actually one of the major categories of mechanical energy storage and gravity energy storage technologies.

It is understood that the principle of Energy Vault's gravity energy storage technology (hereinafter collectively referred to as "gravity energy storage") adopted by China Tianying is to convert electrical energy into potential energy through a motor, and lift the gravity block to a certain height. Put down the gravity block, drive the generator to convert potential energy into mechanical energy, and then convert the magnetic field lines into electrical energy through the rotor. From the perspective of construction conditions, physical energy storage methods such as pumped hydro energy storage and compressed air energy storage have relatively high requirements on the geographical environment and geological conditions. Gravity energy storage has a wider range of applications, can store surplus energy generated by a large amount of renewable energy in a medium to long time, can have a long service life, and has the advantages of pumped hydro energy storage.

In terms of cost, technologies such as superconducting energy storage and supercapacitor energy storage are costly, and even pumped hydro storage has a long construction period. The unit power cost of the gravity energy storage device is low, and the main investment cost is the large-capacity motor/generator set and the track for transporting the heavy block.

Although electrochemical energy storage has grown rapidly in recent years, chemical energy storage methods such as lithium-ion batteries have short cycle life and relatively high safety risks. In contrast, gravity energy storage has no chemical battery recycling problems, no harmful substances, low maintenance costs, and low raw material costs.

Classification of energy storage technology Classification of energy storage technology

The relevant person in charge of China Tianying introduced that the gravity energy storage technology route uses mechanical equipment with rotating shafts (synchronous generators, turbines, induction generators, etc.) to realize energy conversion. Since the synchronous generator is a rotating element and has a large moment of inertia, when the system is disturbed, the generator can quickly respond to the load change, release the kinetic energy of the rotor, prevent the frequency from changing abruptly, and buy time for the system to rebuild the power balance. This is very valuable for the future new energy power system.

Large-scale consumption and utilization of renewable energy

According to reports, EV1, the first generation of gravity energy storage technology, has completed the first 35MWh commercial demonstration project (EV1) in Switzerland in 2020, and has achieved grid connection with the Swiss National Grid. At present, China Tianying is in the process of digesting, introducing and re-innovating the second-generation gravity energy storage technology EVx, and will build the world's first 100MWh gravity energy storage demonstration project in Rudong, Jiangsu.

According to reports, the efficiency of gravity energy storage is higher than that of pumped hydro storage, usually above 85%. This provides a competitive advantage for the marketization of gravity energy storage. Since this technical route has the advantages of high power, high efficiency, long life, and unrestricted location, it is suitable for large-scale consumption and utilization of renewable energy in the west. Technology can realize large-scale "West-to-East Power Transmission" and become an important option for flexible energy regulation.

The relevant person in charge of China Tianying said that the company signed a strategic cooperation agreement with the Energy Investment Professional Committee of the China Investment Association, China Three Gorges Construction Engineering (Group) Co., Ltd., and China Construction Seventh Bureau Xinneng (Shanghai) Construction Co., Ltd. The scope of cooperation includes but Not limited to hydropower, wind power, photovoltaic, energy storage technology (gravity energy storage) and other new energy projects, but also involving new material research and development, equipment manufacturing, scientific research industrialization and technical services in the above fields; , -2.38%) Hydropower Development Group Co., Ltd. signed a strategic cooperation agreement, and the two parties have comprehensively cooperated on gravity energy storage + photovoltaic, wind power, hydropower, nuclear power, etc.

Gravity energy storage has application value in various scenarios of the power system. It is used as a new energy supporting energy storage power station on the power generation side; it provides auxiliary services on the user side, and can also play a conventional energy storage role in the industrial park. At present, the application of China Tianying is mainly concentrated on the grid side. The company signed a strategic agreement with State Grid Jiangsu Integrated Energy to provide support and services for the grid.

Huaxi Securities analyzed that gravity energy storage has many advantages such as high safety, environmental protection, suitable for "distributed" energy storage, long life, and low cost, and the technology has great potential for development. China Tianying has achieved "from 0 to 1" in the field of gravity energy storage, and the company's development is expected to open up new space.