Full charge

Audi has opened a Germany’s largest electricity storage facility in Berlin to look at ways of efficiently integrating electric vehicles into the energy industry. Situated at the EUREF campus – a collection of some 150 companies working on future energy solutions – the facility is effectively a working laboratory looking at a range of issues including compensating for fluctuations in the power grid and optimising energy supply.

The 110 metre multi-use storage unit boasts 1.9 MWh of storage and uses used lithium-ion batteries from development vehicles to test various interaction scenarios between electric cars and the power grid. The storage unit is connected to Berlin’s medium-voltage power grid with one megawatt of power, which corresponds to the average charging requirement of around 200 electric cars. With its capacity of 1.9 MWh, the storage unit could supply the entire EUREF campus with electricity independently for just under two hours.

Given the large portion of renewable energies with varying electricity generation in the surrounding area, Berlin offers ideal conditions for the development of intelligent charging control that may be expanded to include a growing number of electric cars as buffer storage in the future. Audi and its project partners intend to conduct a model experiment with wind farms in the area to show how excess green electricity can be buffered on the EUREF Campus in a targeted manner and would mean that wind turbines would no longer have to be taken off the grid in the event of temporary excess electricity production. It is a small building block for a sustainable world of energy and an addition to the industrial storage of large volumes of excess electricity that Audi has been practicing with its power-to-gas plant in Werlte since 2013. 

Rapid-charging stations in the immediate vicinity, where electric cars can charge with up to
175 kW, are a further use case. To ensure that the high electricity requirement is covered in the most cost-efficient way possible and the local power grid is not put under excessive strain, the battery storage unit functions as a buffer here, too. Intelligent integration into the power grid allows the energy reservoir to absorb excess electricity from wind power and photovoltaic systems or the campus’s own combined heat and power plant. This compensates for fluctuations in the grid, counteracts local peak demands, and helps prevent blackouts by stabilising the transmission network.

Aside from research on interfaces for intelligent integration into the power grid of the future, the battery storage unit on the EUREF Campus provides further insights that will be incorporated into future projects. Audi engineers are testing the use of stationary energy storage units in the power grid, and creating a way to reuse used batteries from electric cars, given that these batteries retain the majority of their capacity after being used in cars.