Porsche is using its own second-life EV batteries as a BESS backup in Leipzig

A battery energy storage system (BESS) the size of almost two basketball courts, consisting of 4,400 second-life battery modules, is being used to supply the Porsche Plant Leipzig with power.

According to the Stuttgart-based luxury car brand, the batteries were taken from pre-series and works vehicles and are now being put to use as a stationary energy storage system at the end of their service life.

The 5MW/10MWh system can be operated at up to 20% overload for short periods. The 4,400 individual modules are separated into four battery strings, each connected to an inverter and a transformer in a medium-voltage system.

According to the company, the entire system, including the battery blocks, is designed for a useful life of more than ten years and individual battery modules can be replaced individually if necessary.

The electricity for the storage system is partly generated by the plant’s own solar systems with a peak output of 9.4MW. When peak loads occur, the storage system helps to reduce them.

The stationary battery storage system will also be integrated into the balancing market in every marketable form by the end of the year, including peak shaving, as a grid stabiliser for the upstream distribution grids.

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Explaining the goals of the project, Alwin Schmid, head of Electrical Engineering at Porsche, said: “Of course, this is about environmental aspects and the core issue of the energy supply. But it was also important to us to take a pioneering role with the storage system.

“In this unprecedented model project, we were able to combine a number of different goals, including peak load capping, optimisation of self-consumption and simultaneous participation in the energy market.”

Said Jonathan Dietrich, overall project manager for battery storage: “We wanted to create electricity storage capacities for the Leipzig plant in order to make the site even more economical and to increase its degree of self-sufficiency. So it was only logical to use batteries from Taycan preseries vehicles instead of recycling them.

“We hope to gain insights from the project in order to be able to equip other Porsche locations with similar systems and capabilities in the future. At the same time, we can utilise batteries from test cars that are no longer suitable for demanding use in the vehicle for a second useful deployment before their final recycling.”

The BESS project idea originated in the Porsche Environmental and Energy Management unit and was based on a feasibility study in collaboration with the University of Applied Sciences Zwickau.

According to Porsche, since 2017, they have been using only electricity from renewable energy sources. The German production sites in Stuttgart-Zuffenhausen and Leipzig, for example, receive their energy from green electricity and biomethane. The Leipzig site also obtains district heating from biomass.