China is turning its roads into a giant energy laboratory. With more than 25 million electric cars on the road, the country is not only leading the clean mobility revolution, but is experimenting with a model that could change the very structure of the electricity system: vehicle-to-grid, or V2G. It involves using vehicle batteries as small mobile power plants, capable of storing energy and returning it to the grid when needed. It is one of the most promising frontiers of the energy transition, Carbon Brief reports in an in-depth analysis.
A distributed reserve
The principle is that of a bidirectional grid: when electricity demand is low, vehicles absorb energy, ideally produced from renewable sources. When the grid is under pressure—for example, during peak hours or periods of low wind and solar generation—the batteries return some of that stored energy. In this way, the vehicles become a balancing element in the system, helping to stabilise energy flows and reduce the waste of renewable generation that still remains a significant problem in China today.
The potential is enormous: millions of grid-connected cars can provide a flexible distributed energy reserve, capable of responding in real time to fluctuations in demand. It is a crucial building block for an electricity system that, as Carbon Brief points out, is struggling to integrate the very rapid growth of solar and wind. The path, however, is not easy. Experiments launched in several cities—from Shanghai to Shenzhen—show encouraging results but also many limitations. Two-way charging infrastructure is expensive, and only a fraction of car models are compatible with the technology. In addition, battery life remains an issue: charging and discharging cycles could reduce their useful life, making the investment less attractive to consumers.
New rules are needed
Another obstacle is the market. For V2G to work on a large scale, new rules are needed: dynamic tariffs, digital platforms, specialised operators, a communication network capable of coordinating millions of exchange points. In China, some logistics companies and municipalities are already experimenting with remuneration schemes: those who supply energy to the network can earn non-negligible monthly fees. It is a form of active citizen participation in energy management, but it requires trust and transparency. Technology, in short, is only part of the solution: the challenge is primarily cultural and regulatory.
If it can overcome these obstacles, V2G can become a pillar of China’s energy transition. Electric cars would no longer be mere means of transportation, but dynamic components of a more resilient power grid capable of integrating large amounts of renewables. It is a vision that could also inspire Europe, where the problem of intermittent clean sources is increasingly relevant. In Italy, the expansion of solar and wind requires storage solutions and flexibility: vehicle-to-grid technology could be a valuable tool, provided we build a regulatory and technical framework that makes it viable.
The Chinese lesson, Carbon Brief concludes, is that the energy transition comes not only from large power plants and industrial facilities, but also from millions of individual choices coordinated by a smart system. A piece of the energy future, perhaps, is already parked under the house.
