In order to reduce emissions and enhance energy security, renewable power sources are being introduced proactively. As the fraction of these sources on a power grid grows, it will become more difficult to maintain balance between renewable power supply and coincident demand, because renewable power generation changes frequently and significantly, depending on weather conditions.
As a means of resolving this imbalance between supply and demand, vehicle-to-grid (V2G) technology is being discussed, because it enables vehicles to contribute to stabilizing the power grid by utilizing on-board batteries as a distributed energy resource as well as an energy storage for propulsion.
The authors have built a plug-in vehicle with a capability of backfeeding to the power grid, by integrating a bi-directional on-board AC/DC and DC/AC converter (on-board charger) and a digital communication device into the vehicle. The vehicle is interconnected to a power regulation market in the United States. By participating in the regulation market, the authors verify that this V2G-capable car is able to create a value of more than $100/kW annually by charging and discharging power.
In order to widely adopt V2G technology in the real world, it is necessary to establish an overall system that enables adoption of the technology by interconnecting individual vehicles, users, grid operators, utilities, and governmental organizations. Standardization is also important for large-scale deployment of the technology, an area in which SAE has already been moving forward.