China puts 10 MWh sodium-ion battery storage system into operation
Energy storage of green electricity is progressing in China. In addition to lithium-ion batteries, sodium-ion batteries are now also being used on a large scale
The Chinese battery storage system consists of more than 22,000 sodium-ion storage cells.
(Image: China Southwestern Power Grid)
The Chinese energy company China Southwestern Power Grid has commissioned what is probably the first large-scale battery storage station based on cost-effective sodium-ion technology in Nanning in the autonomous region of Guangxi. The system can store 10 MWh of energy.
The system consists of more than 22,000 210 Ah sodium-ion battery cells. They can be charged to 90 percent within twelve minutes, according to a statement from China Southwestern Power Grid. However, the 10 MWh battery storage system is only the first expansion phase. It is part of an overall project that should be able to supply 100 MWh of energy. The entire system will then supply 73 million kWh of green electricity to cover the electricity needs of 35,000 private customers. This should reduce CO₂ emissions by 50,000 tons.
Advantages of sodium-ion batteries
Sodium-ion batteries and conventional lithium-ion technology are largely based on the same chemical processes. They store and release energy by reversibly dissolving and embedding cations between the positive and negative electrodes. The difference lies in the material used. The raw material reserves for lithium-ion batteries are limited. Lithium is often extracted in conflict-ridden regions of the world. The raw materials for sodium-ion batteries, on the other hand, are quite inexpensive and are easier to extract.
In addition, sodium-ion batteries are said to have a higher performance at low temperatures and are therefore better suited to storing energy in larger quantities. However, the sodium-ion battery storage system in Nanning does not work entirely without technical thermal management: a thermal management system keeps the temperature difference between the 22,000 cells within a temperature range of 3 degrees Celsius. This has also made it possible to extend the time in which the cells thermally expand from 30 minutes to two hours, writes China Southwestern Power Grid.
According to China Southwestern Power Grid, the cost of sodium-ion batteries can be reduced by around 20 to 30 percent compared to lithium-ion technology when used on a large scale. There is also a reduction in costs per kWh of electricity. Here, the company expects a reduction to 0.0276 US dollars per kWh.
The battery storage system in Nanning is part of a Chinese initiative to build new energy storage systems. The total capacity of all existing facilities amounts to 35.3 million kWh. More than 95 percent of this is electrochemical storage - including lithium-ion batteries.
(olb)