Electricity from braking energy illuminates subway stations in Vienna


After the successful pilot trial started in 2018, a second inverter system was put into operation at the U1 station Altes Landgut.

There are two ”Brake Energy” plants: one in the U2 station Hardeggasse and one in the U1 station Altes Landgut.

Data show that these power plants can “brake” around 3 gigawatt hours of electricity per year. This corresponds to the electricity consumption of an average of 720 households and saves around 400 tons of CO2.

How the subways function as small power plants

It happens thousands of times a day: whenever a subway stops in a station, braking energy is released.

Much of the energy generated is re-fed and drives other approaching trains. But what to do if there is no train in the station at the same time?

Until a few years ago, the resulting energy remained unused and was converted into heat.

Thanks to the “Brake Energy” project, however, this energy can be recycled: If there is no other train in the station, the excess braking energy is fed into the 20kV alternating current network of the Vienna lines.

Escalators, elevators and lighting are supplied with recycled electricity in stations.

Next plant planned for U4 station Ober St. Veit

“In the future, four more plants are to be built. The next plant is planned for 2021 at the U4 station Ober St. Veit,” announces Günter Steinbauer, Managing Director of Wiener Linien.

One third of Vienna’s rail vehicles run with CO2-free electricity

Already one third of Vienna’s rail vehicles are powered by recycled electricity.

As a pilot project, photovoltaic films were installed for the first time at the Ottakring station in autumn 2019, which supplies 50 percent of the entire station with solar power at peak times.

Thanks to the resource-saving use of energy, the Vienna lines are responsible for only one percent of Vienna’s CO2 emissions.

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