In an effort to advance energy integration and improve grid flexibility, Northwest China's Gansu province is beefing up cutting-edge vehicle-to-grid (V2G) technology and enabling electric vehicles to function as "power banks" for the power grid.

Allowing energy stored in an EV battery to be replaced back into the power grid, V2G technology can facilitate the bidirectional flow of energy between vehicles and the grid, breaking the traditional limitation of EV charging patterns that solely draw power from the grid, and can now be used to support peak load adjustments while generating additional income for EV owners.

Using V2G-enabled fast-charging stations, EV owners can capitalize on time-of-use electricity pricing by charging during off-peak hours at lower rates and selling power back to the grid during peak hours at higher prices, earning profits from the price gap, said State Grid Gansu Electric Power Co, a local power operator that completed the building of its first V2G station in Gansu this month.

"Looking ahead, EVs will no longer be just a mode of transportation. Owners can participate in orderly charging and discharging, leveraging their cars to support grid operations, reduce electricity costs and gain extra income," said Liu Caixia, a manager for charging and battery swap operations at State Grid Gansu Integrated Energy Services Co Ltd.

In addition, when EVs serve as energy storage units, they participate in peak shaving and valley filling, and provide extra flexibility to the grid. The functions are expected to help stabilize grid fluctuations, enhance renewable energy integration and reduce grid losses, said Liu, adding that, "This new ecosystem will help enhance energy efficiency, contribute to grid stability and eventually further promote the development of the EV industry."

Jointly issued by the National Development and Reform Commission, the National Energy Administration and other departments, China issued its first national policy document on V2G last year, aiming to strengthen the integration of NEVs and the power grid.

Targeting the establishment of over five demonstration cities and 50 two-way charging and discharging pilot projects by the end of 2025, it said NEVs are expected to become a critical component of the energy storage system by 2030, providing the power system with about 10 million kilowatts of bidirectional flexibility.

China's EV fleet is projected to reach 300 million vehicles by 2040. If adopting 15-kW bidirectional charging stations, the facilities are expected to provide 2.9-3.5 billion kW of electricity to the grid's overall capacity, equivalent to 50 percent of the nation's non-fossil fuel energy capacity at that time, said Chinese news outlet Yicai.

To date, Gansu has already begun deploying V2G charging stations in Dunhuang and Habancha village of Lanzhou, based on the construction of a smart microgrid network with flexible alternating current/direct current (AC/DC) integration.

Combining photovoltaic power generation, energy storage and charging infrastructure, Gansu's first demonstration project for an integrated smart microgrid network was completed in Dunhuang this month. The project features three DC fast-charging zones and three AC slow-charging zones, with a maximum single-charging output of 120 kW, providing efficient services for various types of EVs.

The project also includes one V2G charging station with a maximum discharge capacity of 120 kW and is expected to provide EV owners with convenient charging and discharging services while reducing electricity costs, said Yue Lin, a deputy manager at State Grid Gansu Integrated Energy Services Co Ltd, the project's operator.