As a vanadium flow battery, the new energy storage system differs from the common lithium-ion batteries in use in today's electric vehicles and smartphones. They use massive tanks to store chemical energy in the form of liquid electrolytes, which can be converted into electricity by passing the fluid through a special membrane.

This makes flow batteries a relatively cheap energy storage solution and an attractive one when it comes to renewable energy as they can store it away for months at a time. This lends itself well to the storage of wind and solar energy, which can be intermittent by nature, and could see these sources leveraged to help cities deal with spikes in energy demand.

We’ve seen this idea explored through a 120MW redox flow battery built in underground salt caverns, supplying enough daily power for 75 000 homes in Jemgum in northwestern Germany. The Dalian Flow Battery Energy Storage Peak-shaving Power Station won’t quite meet this output to begin with, but is designed to be scaled up and eventually output 200MW with an 800MWh capacity.

It is therefore billed as the world’s largest flow battery so far and China’s first large-scale chemical energy storage demonstration project. It was hooked up to the grid in Dalian last Thursday and is expected to shore up the reliability of power in the region by filling valleys and absorbing peaks in its energy demands.

Renewable energy sources will charge up the batteries during the "valley" load period, converting electrical energy into chemical energy. This will be converted back into electrical energy for consumers once again during peak grid load periods, serving as a power bank for the city.

More broadly, the station is intended to demonstrate how flow batteries can improve reliability and manage spikes in energy demand in China, as well as aid the country's efforts to reduce carbon emissions. 

New Atlas