Braking energy recovery on the Brussels metro network (STIB)

Braking energy recovery technologies have been studied at STIB since 2004. After meeting with firms presenting their latest products, STIB soon realised that it would have to adopt a global approach in order to grasp the different aspects of this field.

Research projects with local universities produced interesting results regarding the implementation of supercapacitor-based technologies, particularly for the metro network. A first version of a simulation tool was tested for calculating the energy flows between the vehicles and potential energy savings. This work was deepened during the Ticket to Kyoto project and led to the development of a robust simulation tool able to evaluate any type of braking energy recovery equipment. In parallel, a multicriteria analysis was completed to see what technology would best suit the STIB’s needs.

Since STIB owns its high-voltage electrical network, inverters appeared to be the most cost-effective solution in this context. A European tender was launched and three suppliers were invited to test their system on the network for several weeks in order to compare their efficiency and the delivered savings. This empirical approach produced useful insights on the way braking energy can be recovered by the use of inverters. The best system is now progressively installed on the entire metro network.

BRAKING ENERGY RECOVERY ON THE BRUSSELS METRO NETWORK (STIB)  BRAKING ENERGY RECOVERY ON THE BRUSSELS METRO NETWORK (STIB)
 
Technical data (extrapolation for deployment on whole lines 2 & 6)

Investment costs (€)

€1,800,000

Energy savings (%)

9%

Annual energy savings (kWh)

3,400,000 kWh

Annual CO2 savings (TCO2)

568 TCO2

Payback time (years)

5 years


Investment sheet: STIB braking energy