Those advocating for electric vehicles (EVs) as the road to realizing a low-carbon future have faced a great deal of criticism, as of late. The concerns of these EV critics are not entirely unfounded. Lacking the necessary Vehicle-to-grid (V2G) technology, the energy used to power EVs continues to be sourced from fossil fuels; carbon neutrality will continue to prove elusive. Vehicle-to-grid (V2G) describes a system in which plug-in electric vehicles, such as battery electric vehicles (BEVs) and plug-in hybrids (PHEVs), communicate with the power grid to sell demand response services by either delivering electricity into the grid or by throttling their charging rate.

With the help of V2G, EVs are able to form a mini-loop with the electricity grid, in which V2G vehicles provide power to help balance loads by "valley filling" and "peak shaving". The development of this technology will contribute considerably to balancing power supply with grid capacity. V2G vehicles have unique advantages in China as the traditional pumped-storage hydroelectricity for load balancing is not feasible in China, due to the geography and energy map mismatch. Therefore V2G is rather a practical option for load balancing in China.

State Grid Corp, the largest power company in China, demonstrated the V2G technology at the Expo 2010 Shanghai China. “By using the rechargeable batteries of electric vehicles, it becomes possible to stably operate the electricity grid,” said Li Shu, Preparatory Department for Enterprise Pavilion at the Shanghai Expo, Publicity and Promotion, Shanghai Municipal Electric Power Co, which is affiliated with State Grid. For example, when the output from renewable energy sources, such as solar power, drops drastically, electricity can be supplied from several tens or hundreds of EVs to the grid to reduce the number of electric outages. Shu said that the full-fledged introduction of the V2G technology depends on the dissemination of EVs.  State Grid developed an EV rapid charger that supports the V2G technology. When an EV is connected to this charger, it automatically switches between charging and discharging in accordance with the grid’s supply and demand situation.

Source: Telematicnews article on demonstration

Read more:

Wikipedia article on Vehicle-2-Grid technology
Policy briefing, the Climate Group, pp. 15-16 (pdf)  (only in Chinese)

All Analysis & Synthesis Posts