GUANGZHOU, Aug. 27 (Xinhua) -- A Guangzhou resident surnamed Chen has made a tidy sum of more than 200 yuan (about 28 U.S. dollars) by simply parking his new energy vehicle (NEV) in the garage. The secret behind this new source of income? He has fed around 60 kWh of electricity back into the power grid.

The V2G service, short for Vehicle-to-Grid interaction, enables NEVs to charge and store electricity using dedicated charging piles during off-peak hours. During peak demand periods or when electricity is needed, these vehicles can feed the stored power from their batteries back into the grid.

NEV owners can therefore take advantage of electricity pricing by charging their vehicles during off-peak hours at night when rates are low, and discharging back to the grid during daytime peak hours when rates are high, thereby earning a profit from the price difference.

The service was recently launched on a pilot basis by the Guangzhou Power Supply Bureau and the Chinese automaker GAC Group in south China's Guangdong Province. It is now available to owners of NEVs produced by GAC.

The battery, one of the core components of an NEV, can account for up to 50 percent of its cost. For car owners considering the service, the lifespan of the battery is often among their top concerns.

Normally, it takes about 1,000 charging cycles for an 80 kWh LFP battery, commonly used in NEVs, to reach the disposal standard of 600,000 kilometers, explained Liang Tangjie at GAC.

"LFP batteries can withstand more than 3,000 cycles while still retaining over 80 percent of their capacity, which means more than half of their buffer potential remains unused. That's where the idea of V2G comes from," Liang added.

As Guangdong is home to more than 3 million NEVs, each equipped with a 65 kWh battery on average, the vehicles collectively represent more than 200 GWh of mobile storage.

To make V2G a reality, electric power companies and automakers have to work closely together. In May, Guangdong introduced its first discharge tariffs, setting the rate at about 0.77 yuan per kWh of electricity fed back to the grid during peak hours, compared to the electricity fee of 0.22 per kWh in the slack hours.

Meanwhile, GAC developed bidirectional charging piles and embedded discharge protocols into models such as its Hyper series, allowing vehicles to supply power legitimately and safely.

"It's convenient to use the service through the app. You can set the amount of electricity to release, and the system takes care of the process automatically," Chen said.

Liang said the service is especially suitable for office workers in business parks who commute by car and leave their vehicles parked during the daytime, the very hours when power demand peaks. It is also a good fit for those who mainly rely on public transport on weekdays and use their cars on weekends, as their parked vehicles can provide power during the day.

Beyond benefits for drivers and industry participants, V2G also helps electric power companies in balancing electricity demand throughout the day, contributing to a stable grid.

In the first half of 2025, China's electricity consumption rose 3.7 percent year on year to about 4.84 trillion kWh, according to the National Energy Administration (NEA). Guangdong, the nation's manufacturing powerhouse with a population of over 127 million, used 433.3 billion kWh, accounting for nearly one-tenth of the national total.

"The high temperatures and extreme weather bring challenges to safe and stable power supply," said Liu Mingyang, an NEA official.

"In the past, electric power companies sometimes had to cut power or impose restrictions to prevent overloads," said Zhao Wanmei of China Southern Power Grid. "Now, we can turn to electric vehicles for support."

A fully charged NEV stores about 65 kWh of electricity, enough to power a one-horsepower air conditioner for around 60 hours, or 10 such units for 6 hours, providing important backup during peak demand periods.

However, challenges still remain. Automakers must ensure their batteries can withstand frequent charging and discharging cycles without compromising safety, while manufacturers also need to work toward universal discharge protocols and industry-wide standards.

Local governments will also need to refine tariffs and launch promotional programs to encourage participation, gradually phasing out subsidies as infrastructure costs fall.

Looking ahead, Guangdong's provincial grid operator plans to establish a vehicle-grid interaction alliance with automakers including GAC and BYD, as well as charging infrastructure companies. The alliance aims to mobilize 600,000 NEVs in the Pearl River Delta by 2028, effectively creating a virtual pumped-storage power plant.

"In the future, your car will not just take you places, it could help power your city through critical times," said Chen Jianqiang, an engineer at the provincial grid.