Braking energy recovery on the Bielefeld light rail network (moBiel)

moBiel intended to invest in a braking energy recovery system to decrease the energy consumption of its light-rail network. The first step was a network study done by an external consultancy, to gain an overview of the potential savings and identify potential locations for implementing the recovery systems. In a second step, moBiel launched a European tender and opted for a flywheel and two inverters.

The flywheel is located at the end of one line but this line will be extended by 1.5 km in a near future. Due to its weight (10 tons), the ground below the substation had to be consolidated. The system is very noisy (96 dB(A)) and obliges staff to wear acoustic protection when close to the equipment. During installation, some jerking problems occurred with various types of vehicles when braking, but this could be fixed. The results of the flywheel exceeded the expectations stemming from the network study.

moBiel also invested in two inverters located on two different tram lines. The inverters are less heavy and not noisy. The results of both systems are in line with expectations and the systems are currently fine-tuned to optimise energy savings. A third inverter will be purchased in the near future.

BRAKING ENERGY RECOVERY ON THE BIELEFELD LIGHT RAIL NETWORK (MOBIEL)   BRAKING ENERGY RECOVERY ON THE BIELEFELD LIGHT RAIL NETWORK (MOBIEL)   BRAKING ENERGY RECOVERY ON THE BIELEFELD LIGHT RAIL NETWORK (MOBIEL)
 
Technical data

Investment costs (€)

€825,000

Energy savings (%)

6%

Annual energy savings (kWh)

900,000

Annual CO2 savings (TCO2)

470 TCO2

Payback time (years)

Maximum 10 years (5 years with T2K funding)


Investment sheet: moBiel braking energy