Testing the future in a real-world laboratory
The ideas factory in the heart of Berlin
The EUREF Campus in Berlin is often regarded as an emblem of the future, a symbol of the energy transition. But it’s far more than just a symbolic backdrop for speeches and declarations of intent (even if it does serve that function too: German Chancellor Angela Merkel has spoken there before on the topic of
e-mobility). The focus is on practical, hands-on problem-solving. Located by the historic “Gasometer” in Berlin’s Schöneberg district, the campus is a real-world laboratory where over 3,500 people working for 150+ businesses, institutions, and start-ups carry out work, research, and studies in the areas of energy, transportation, and
sustainability. Day in, day out, this is where the future is being finetuned: where new products are developed, new patents filed, new services rolled out.
Wherever the cutting edge of technological progress is, that’s where you’ll find Audi too. Last year, the brand with the four rings opened Germany’s largest multi-use battery storage unit at the campus. Consisting of batteries from old Audi e-tron development vehicles, it has a capacity of 1.9 MWh: enough to power a four-person household for around six months.
A huge mobile energy storage unit
Using old car batteries as emergency generators would be one way to give them a second lease of life. But the Audi engineers are thinking far bigger than that. The question they want to answer is: “How can we integrate electric vehicles into the energy transition?” That was how Dr. Stefan Niemand (Audi’s former head of electrification) formulated the team’s mission when the unit opened in May 2019. “The aim is to study two ways in which e-tron batteries can be integrated into the power grid. Firstly, intelligent charging/discharging management while the batteries are still being used in vehicles as portable energy stores. Secondly, the use of second-life battery banks to stabilize the grid and secure the power supply.”
The storage unit at the EUREF Campus allows both these applications to be simulated, measured, and analyzed based on large datasets. Although the battery modules have been removed from vehicles and linked together, for test purposes they can simulate a scenario where they are still installed in separate e-trons and have simply been hooked up to the grid to charge. The resulting network is one of the things the Audi engineers are testing: “As the number of electric models rises, a huge mobile energy storage unit is growing with it,” explains Alexander Kupfer, who works on sustainable product development at Audi. “By 2025, newly sold Volkswagen models alone will have a battery capacity of around 150 GWh. Purely numerically speaking, that’s enough to power an industrialized nation like Germany for around two hours. But cars are only in use around five percent of the time on average; they spend the other 95 percent parked. So it makes sense to try and utilize this enormous potential.”
A dynamic duo: renewable energy and e-mobility
If electric cars are connected to the power grid and their storage capacity can be intelligently managed, they will form a high-powered network that could be used in the future to stabilize and optimize the energy supply. Intelligent integration into the power grid allows the energy reservoir to absorb excess electricity from wind power and photovoltaic systems. This compensates for fluctuations in the grid, stabilizes the transmission network, and smooths load peaks, something which would otherwise require special facilities. In addition, the power supply is optimized in terms of its CO₂ neutrality.
In order to simulate these kinds of scenarios on a small scale, a model experiment is being conducted with wind farms in Brandenburg and Mecklenburg-West Pomerania. Excess green electricity is buffered at the EUREF Campus in a targeted manner so that wind turbines no longer have to be taken off the grid in the event of temporary excess electricity production. “At the moment, our battery storage unit at the EUREF Campus is just a small building block for a sustainable world of energy, but in a few years it could play a major role. I’d go so far as to say that e-mobility is crucial to achieving a functioning power grid based mainly on renewable sources,” says Alexander.
A second life for batteries
Aside from research on intelligent integration of electric cars into the power grid of the future, the battery storage unit at the EUREF Campus also allows another important aspect of e-mobility to be addressed: how can still-functional batteries be reused after the end of a car’s life cycle? “The batteries generally still have good residual capacity,” explains Alexander. At the EUREF Campus, engineers are testing how used batteries could be utilized for auxiliary and buffer storage on local power grids with varied charging and discharging scenarios. The used-battery storage unit is connected to Berlin’s medium-voltage power grid with one megawatt of power, and helps to compensate for power fluctuations.
“What this means is that some batteries bound for recycling could end up being reused on the power grid for a while first. Only once they can no longer serve this function would they be broken down into their individual components using state-of-the-art recycling processes; another important task for Audi and its partners is to develop integrated, sustainable methods for recycling,” explains Alexander. “And even then the journey wouldn’t be over, since some of the materials will be reused in new batteries.” In summary: by the time an Audi e-tron battery reaches the end of its service cycle, it will have not just one but two eventful lives behind it—and will have a good chance of being reborn all over again.