World's largest flow battery connected to the grid in China

The Chinese city of Dalian has just switched on a world-leading new energy storage system, expected to supply enough power for up to 200,000 residents each day. With an initial capacity of 400 MWh and output of 100 MW, the Dalian Flow Battery Energy Storage Peak-shaving Power Station will serve as a power bank for the city and assist in its uptake of renewable energy sources such as wind and solar.

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, which can be intermittent by nature, and could see these sources leveraged to help cities deal with spikes in energy demand.