TransnetBW & Tesla: Germany’s redispatch ready for flexibility

TransnetBW & Tesla: Germany’s redispatch ready for flexibility
Grid development planning for Baden-Württemberg. Image courtest Transnet.

After testing power grid stability with Tesla’s Powerwall PV storage systems, German TSO TransnetBW has found that it is presently possible to integrate flexibility into redispatch orders.

The finding comes from the TSO’s PV-Shift pilot project, showing that it is already possible today to integrate the smallest of flexibilities into redispatch, when the TSO puts in a request to power plants to adjust power to avoid congestion.

Transnet CEO Rainer Pflaum commented on the importance of such micro-flexibility to stabilise the grid, a concept proven by the TSO’s joint project with Tesla.

“To ensure a stable power grid, we must integrate this flexibility into grid operations intelligently and on a voluntary basis in the future…It is now of central importance to set the legal and regulatory course in order to quickly leverage the proven potential.”

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According to Transnet, a study carried out by the University of Stuttgart on their behalf concluded that in Baden-Württemberg alone, which is Transnet’s operating area, there is high savings potential through the integration of small-scale flexibilities in electricity redispatch.

“This pilot project by TransnetBW and Tesla impressively shows that home electricity storage devices such as the Tesla Powerwall can make a reliable contribution to grid stability and can thus support the transition to 100% green electricity in the grid,” stated Mark Reijerkerk, who leads Tesla’s sales for residential and small commercial energy storage in Europe.

“In addition, it is clear that Powerwall owners are ready to actively support the necessary transformation towards more grid flexibility.”

Days without activation (left) compared with days with activation (right). Captions left to right: battery chargin power, PV-generation, grid reference, PV feed-in, battery state of charge. Image courtesy TransnetBW.


With PV-Shift, the two project partners jointly developed a redispatch product tailored to the technology, which could be fully integrated into TransnetBW’s operating processes.

The entire process chain was tested in practice: from the operational processes in the main control room to the activation of the more than 100 decentralised systems (around 500kW in total) by Tesla.

The underlying  principle was that in times of high load or low feed-in, the power grid can be relieved by shifting the charging processes of the Powerwalls. The solar systems would feed electricity into the public grid as required and on the instructions of TransnetBW.

This helps to stabilise the power grid in a cost-efficient, resource-saving and climate-neutral manner.

The pilot project was accompanied by an extensive data analysis, which according to Transnet confirmed the need for a redispatch product.

This analysis also outlined the central challenge of further proving the flexibility service and the forecasts of the potential for providing redispatch from home storage.

Exact provision of such redispatch, they state, is particularly important for the operational planning processes and for the system balance sheet.

Transnet and Tesla‘s results come months after release of the Federal Network Agency’s electricity supply security report of February 1, 2023, which estimates that up to 50GW of shiftable load could be available throughout Germany by 2031 through minimal flexibility.