SHENZHEN, May 16 (Xinhua) -- Between 1:30 p.m. and 2:30 p.m. Wednesday, 20 new energy vehicles (NEVs) had been plugged into the charging poles in a demonstration charging station, located in Bao'an District of southern Chinese metropolis of Shenzhen, not to fill up their batteries, rather, to inject electricity back into the grid.

They were among the 1,473 NEVs participating in a successful demonstration of commercial application of vehicle-grid-interaction. Among them, 53 sent the electricity back to the grid while the rest of the car owners decided to forgo this time slot to charge their vehicles during the peak period.

Shenzhen's power supply bureau under China Southern Power Grid forecasted that the electricity consumption would reach its peak during the time of the day. To guarantee a stable power supply, the administrative center of Shenzhen virtual power plant lodged a request for peak cut to the vehicle-grid-interaction platform run by the China Southern Power Grid.

Subsequently, subscribers to a NEV owner app were invited to participate in the Wednesday demo run, incentivized by a reward of 4 yuan (about 56 U.S. cents) per kWh of electricity in reverse flow to the grid, and a discount of 0.8 yuan per kWh of electricity drawn from the grid for those charging their cars within the 2:30 p.m.-3:30 p.m. time slot.

"It costs me 0.5 to 0.6 yuan in charging 1 kWh of electricity in the evening. Signing up to this demo run, I expected to earn a profit of over 60 yuan for giving back 20 kWh of electricity to the grid," said a car owner surnamed Yuan. "It's a good deal."

Having confirmed the technical and commercial feasibility of such vehicle-grid-interaction, the demo run has also laid ground for larger-scale application in the future, said Chen Mu with the Shenzhen's power supply bureau.

Shenzhen is home to over 1 million NEVs with a potential power storage of NEV batteries reaching 50 million kWh, almost equivalent to the capacity of five medium-sized coal-fired generating units.