China inaugurates world’s largest redox flow battery

After six years of work, the first 400 MWh of a giant stationary vanadium battery have been connected to the Dalian city grid.

China is on the verge of breaking a new world record in the field of energy: the the largest vanadium redox flow battery ever built. A feat which is not yet complete, but which has already taken solid roots.

On June 5, the administration of Dailan, a city in the northeast of the country, activated the first phase of the maxi storage plant.

Up to 100 MW of power and 400 MWh of capacity From now on, they will provide various services to the local electricity network, such as the regulation of peaks generated by solar and wind power plants, black start-ups and demand response. With the ultimate goal of doubling performance to 200 MW and 800 MWh.

But even in its current state, Dailan’s redox flow battery outperforms Sumitomo Electrics’ predecessor. The Japanese company had activated a 17MW/51MWh plant in Hokkaido in April this year, earning it the top spot.

Redox flow batteries, how do they work?

In recent years, flow batteries have started rolling out of the lab and into the market, fueled by new advances in chemistry and design. Structurally, they consist of two reservoirs of liquid electrolytes, one positively charged and the other negatively charged, which are pumped into a membrane separator inserted between the electrodes. The transition activates a reversible electrochemical reaction, which makes it possible to store the electricity and to restore it later.

The most marketed application today is the “full flow” inorganic solution based on vanadium, in which the two electrolytes are composed of this metal. This solution offers a lower energy density than lithium-ion technology (around 25-30 Wh/kg versus 110-160 Wh/kg), but still has interesting advantages.

For instance, is capable of reaching very high abilitieswhich makes it suitable for large energy storage facilities.

They have a long lifespan, excellent charging and discharging cycle stability, flexible layout and do not require load leveling. Moreover, the particular architecture of these batteries makes them practically rechargeable an unlimited number of times.

At the Dalian plant, the technology was provided by manufacturer Rongke Power, a spin-off from the Chinese Academy of Sciences, which oversaw the project throughout its phases.

The work represents the first project approved under a nationwide program to build large-scale flow batteries in China, launched by the government in 2016 as part of a broader strategy on energy storage.

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