To connect electric vehicles to the power grid seamlessly, engineers at Fraunhofer ESK have specified and implemented the required communication interface as part of the EU-sponsored SMARTV2G project (smart vehicle-to-grid interface).
The aim is to create a system in which electric vehicles use and temporarily store energy. The charging station serves as an active node that communicates with the vehicle and an energy management system in the smart grid. One of the benefits for drivers is access to variable energy rates. This approach also allows the energy provider or grid operator to integrate the electric vehicle into the energy management system of the smart grid. By temporarily storing the energy, it can be fed back into the grid as needed.
As part of the SmartV2G project, engineers analyzed all of the information flows needed to support vehicle-to-grid integration. Using this information as a basis, they identified the relevant infrastructure components, designed the underlying communication architecture and derived the functional and technical specifications. The communication path was then implemented and evaluated.
The extensive communication that occurs between the energy management system and the electric vehicle – whether at the charging station or on the road – provides a more convenient driving experience and leads to improved energy efficiency and lower costs. Information such as location, opening hours, number of open charging stations, current energy rates and available payment options will provide drivers a range of benefits.
Time-shifted charging makes optimal use of the grid’s capacity, a feature that can eventually contribute to maintaining a stable energy network. This is a key issue for energy providers and operators because sufficient renewable energy supplies are not always on-hand and that means drivers have to be highly flexible.
Researchers are creating a uniform, manufacture-independent specification for the E-vehicle-to-charging station communication through ISO/IEC15118. This standard defines a comprehensive exchange of information that is essential for the “smart” charging process. Communication between the charging station and the smart grid will be based on an enhancement of the IEC 61850 global standard. Fraunhofer ESK researchers are the driving force behind the further development of the IEC61850-90-8 specification, which to date has been available in draft form. By combining the two standards, the charging station is transformed into a node that integrates the electric vehicle charging process into the smart grid.
The SMARTV2G (smart vehicle-to-grid interface) project is being funded through the European Union’s Seventh Framework Program (FP7).