Tianjin EV charging station runs on 100% green power

At a comprehensive charging demonstration station in Wuqing district, Tianjin, charging equipment can deliver up to 10 times as much power as a household charger. It can quickly replenish electric vehicle batteries, dynamically allocate charging power based on how much energy each vehicle has left, and help explore bidirectional interaction between electric vehicles and the power grid.

The station also uses solar power and purchases green electricity, achieving a 100 percent green electricity supply across the site. These features show how charging infrastructure is expanding beyond fast charging to include flexible power management, vehicle-grid interaction and cleaner energy supply.

For charging stations, delivering more power to each vehicle is only the first step. When many vehicles arrive at once, how limited charging capacity is distributed also affects how quickly the station can serve them.

The Wuqing demonstration station is equipped with three 480-kilowatt flexible charging stacks. Unlike equipment that delivers a fixed amount of power to each charging point, the flexible system adjusts its output according to each vehicle's state of charge (SOC), a measure of how much charge remains in the battery. When several vehicles charge simultaneously, the system prioritizes those with lower battery levels and allocates more power to them.

"The direct-current fast chargers can deliver up to 10 times the power of a household charger, allowing vehicles to recharge quickly. Drivers can 'get a full charge while spending a little time shopping,'" said Zhang Haining, a charging infrastructure specialist in the marketing department of State Grid Tianjin's Wuqing branch.

"But high-power chargers alone are not enough," Zhang added. "When several vehicles charge at the same time, power must be allocated according to their different needs. That makes better use of the station's capacity, allows it to serve more vehicles simultaneously and helps ease queues during holidays."

As the number of new energy vehicles continues to grow, charging infrastructure is taking on a role beyond replenishing vehicle batteries, with increasing attention to interaction between vehicles and the power grid.

At the Wuqing station, the approach is reflected in four bidirectional V2G chargers. In principle, vehicles can draw electricity from the grid and send power back when demand is high. Charging can also be encouraged at night, when electricity demand is lower.

Liu Zixuan and Zhong Aiyamei contributed to this story.