Porsche tests V2G: The Taycan as a buffer storage

High-voltage batteries from electric cars can act as an intelligent swarm to buffer electricity. This was recently confirmed by a realistic pilot trial conducted by Porsche, the transmission system operator TransnetBW, and the consultancy Intelligent Energy System Services (IE2S). In this trial, five series-production Taycans were connected to the power grid in both domestic environments and laboratory conditions using the Porsche Home Energy Manager (HEM). Beforehand, experts from Porsche Engineering had adapted the software of these control centers for the field trial.

New potential especially for fleets and vehicle parks

“The charging technology of the Porsche Taycan and our products Home Energy Manager and Mobile Charger have great future potential. This was shown by the pilot trial,” says Lutz Meschke, Deputy Chairman of the Executive Board and Member of the Executive Board, Finance and IT at Porsche AG, adding:

“Such a pooling system can be used not only for the control power market. Expanded solutions for green charging and other vehicle-to-grid applications are also conceivable. Moreover, when electric vehicles feed electrical energy back into the grid, for example from private photovoltaic systems, thus contributing to the expansion of renewable energy, this further increases the acceptance of e-mobility.”

The Taycan supports grid stability

With the expansion of renewable energies, control power for safe grid operation will become even more important in the future. Even when wind and sun are not always available, the power grid must always be balanced. If power grids are not stabilized constantly at 50 Hertz grid frequency, power outages can occur. So far, conventional power plants primarily buffer these fluctuations. Using high-voltage batteries as buffer storage would be a win-win situation: Electric car drivers could be financially rewarded for their contribution to control power.

Practical: The pooling system adjusts charging processes in real-time in a coordinated manner

The core element of data communication in the pilot trial is a cloud-based pooling system developed by IE2S. This coordinates the charging processes of electric vehicles. It translates the control power target values of the grid operator into vehicle-specific signals that control the charging processes in real-time. Additionally, the pooling system regulates the high-frequency and time-synchronous bidirectional data transfer. On a test basis, the pooling system was connected to the main control line of TransnetBW in Wendlingen near Stuttgart.Dr. Rainer Pflaum, CFO of TransnetBW, explains:

“A truly measurable milestone: The project team has managed to implement the complex communication infrastructure between our control system and several electric vehicles. At the same time, the strict requirements for providing and maintaining control reserve were met. This allows us to integrate electromobility into the intelligent power grid of the future.”

For safety reasons, high requirements for control power apply in Germany. During the pilot test, detailed measurements showed that the target values from the grid control system are met. This applies to both primary (FCR: Frequency Containment Reserve) and secondary control energy (aFRR: automatic Frequency Restoration Reserve). FCR is necessary for the rapid stabilization of the grid, while aFRR must be fully available within five minutes. Measurements were taken in the control system, at the properties (Taycan, Mobile Charger, and HEM), and in the pooling system. For FCR, the functions of the HEM were extended to include local frequency measurement.

What does this mean?

It is known that electric cars can be wonderfully integrated into the grid as massive buffer storage, but the path to achieving this is not entirely straightforward and often hinges on issues in the details. It is all the more remarkable that Porsche is also putting this into practice and achieving positive results. Especially for fleets, Vehicle to Grid could become an interesting aspect.