Friday, May 10, 2019

Energy Storage Faculty Consortium Project - Germany Day 7 Freiburg Public Transportation (VAG) & Lunch with the Lord Mayor


We began our day by visiting the Freiburg Verkhers AG public transportation agency.  We learned about the variety of sustainable transportation initiatives taken by Freiburg, including the creation of new bus and streetcar tram routes, and the promotion of a car-free pedestrian and bike friendly city center.  One amazing statistic is that the city averages one public transportation trip (by either bus or street car tram), per person, per day.  Our group helped add to that total by boarding the tram and heading out towards one of the terminal ends of the tram system.  Here we disembarked to see one of the city’s newest energy storage innovations.  Verkhers AG installed a flywheel energy storage system to recover energy from the tram cars during braking events.  This energy is then released back to the tram to boost acceleration when leaving the tram stop.  The flywheel measured 1 meter in diameter with a weight of 1.9 tons, and spun at a rate of 3500 rotations per minute.  The generator operates at a voltage of 750V dc and a maximum current of 1500 amps, giving the system a nameplate power rating of 1 MW.   The system saves about 250,000 kWh of electricity per year, preventing 145 tons of CO2 emissions. 

Next on the agenda was a luncheon visit with Freiburg’s Lord Mayor Martin Horn.  Mayor Horn was elected in 2018, and at age 33 became the youngest mayor of what is often considered to be one of Germany’s youngest cities (due in part to the large number of students who reside in Freiburg thanks to the University located here).  The mayor shared with us his vision for sustainable development in Freiburg, and indicated that his election was attributable in part to youthful voters in the municipality, and their strong commitment to renewable energy and environmental protection.  The mayor is hoping to bring a delegation of Germans to the United States later this summer to visit Freiburg’s sister city of Madison, Wisconsin.  We hope to have him visit Madison College to see our new rooftop solar photovoltaic system which is the largest in the state.