China plans to turn electric vehicles into mobile batteries for the power grid

China is developing a system to transform its growing fleet of electric vehicles into mobile storage units to support the national power grid.

As the country moves toward replacing fossil fuels with renewable energy, the government and researchers are looking at Vehicle-to-Grid (V2G) technology to manage massive electricity demands. The Chinese government projects that the number of electric vehicles in China will reach between 110 and 160 million by 2030, potentially growing to 300 to 400 million by 2040.

Because simultaneous charging of millions of vehicles could overwhelm city power grids, officials are promoting V2G systems. This technology allows vehicles to act as both consumers and sources of energy. Owners can charge their cars during off-peak hours and sell electricity back to the grid during peak demand. Ouyang Minggao, a professor at Tsinghua University and a member of the Chinese Academy of Sciences, notes that V2G can also benefit vehicle owners by generating revenue.

Based on a 70 kWh battery, drivers could earn between 15,000 and 75,000 yuans over the life of a vehicle. The system also addresses safety and longevity concerns. Research suggests that well-designed V2G interactions do not degrade batteries faster; instead, they can extend a battery's calendar life by avoiding the wear caused by leaving a battery at 100% charge for long periods.

The 15th Five-Year Plan for building new electrical systems aims for a modular charging capacity of 50 million kilowatts via V2G by 2030. By 2040, this storage capacity could exceed 4 billion kilowatt-hours. By 2050, the total battery capacity of 350 million electric vehicles could reach 25 billion kilowatt-hours, which Ouyang Minggao suggests could meet the entire country's daily electricity demand during an emergency.