Electric vehicles connected to the grid, often called V2G (Vehicle-to-Grid), is not a new idea. But in recent years, this technology has gradually become a reality thanks to the development of batteries, smart chargers and grid management systems.
In essence, V2G allows electric vehicles not only to consume electricity but also to return electricity to the power grid when necessary.
The operating principle of V2G is based on the difference between electricity supply and demand over time. At night, electricity demand decreases sharply when most households, offices and factories stop operating.
At this time, the power grid has excess capacity and electricity prices are usually cheap. Conversely, in the morning and evening during peak hours, demand surges, causing the power grid to bear great pressure and electricity prices to rise.
V2G takes advantage of this difference. Users charge electric vehicles at night at low prices, then discharge part of the battery power back into the grid during rush hours during the day. If effectively applied, the electricity price difference may be enough to compensate for travel costs, even helping drivers almost "drive for free".
This technology is also particularly suitable for the context of rapidly developing renewable energy. Electric vehicles, with large capacity batteries, can act as mobile storage batteries, helping to absorb electricity when in surplus and return it when the power grid is stressed.
However, V2G cannot become a popular trend right now. The biggest challenge lies in technology. Electric vehicles must generate alternating current that is completely synchronous with the 50Hz frequency of the power grid, something that very few car models currently meet.
In addition, both the car and the wall-mounted charger need to be certified according to strict standards of the national power system.
Currently, the V2G programs are still mainly in the testing phase. Some manufacturers such as Nissan, Renault or BYD have introduced compatible car models and chargers, but the scope of implementation is still limited.
According to experts, two-way charging is likely to become more popular in the next year or two, when standards are unified and costs are reduced.
