RET tests supercapacitor technology (March 2011)

In October 2010 the Rotterdam public transport company RET started a pilot project with a supercapacitor to save energy in the tram network.

Storing and releasing energy
Using a supercapacitor, the energy released during braking is stored and can be used over a longer period of time for the acceleration of trams in the network. Tram drivers will not notice the difference. The supercapacitor is placed in a 3.5 meters long container, just outside the city centre. In this part of the network the trams gather just enough speed to make full use of the released braking energy.

Huge energy savings
The supercapacitor costs approximately € 800.000. The investment is partially funded by the Dutch government. Part of the knowledge comes from Siemens that had already gained experience with this type of batteries in Germany and Spain. It is expected the supercapacitor will yearly save RET between € 60,000 and € 100,000 in energy costs.

One year evaluation
The principle of charging and discharging energy could also be applied in other public transport systems such as subways. The test will be evaluated after one year. The results will determine if RET continues with this technology.

RET customizes the length of its metro trains (November 2010)

RET wants to achieve quick-wins by customizing the length of its metro-trains to the number of passengers. After the rush hours some of the metro vehicles are disconnected thus reducing the traction energy during the off-peak hours. This way RET expects to save 5% of its annual energy consumption.

From 4 to 1
This pilot project started in the last months of 2008 and has been evaluated every quarter. During peak hours, RET uses metro trains containing 4 vehicles. During off-peak periods, three vehicles are disconnected so only 1 vehicle remains. This substantially reduces the traction energy on the tracks. By not continuously using all vehicles, the maintenance costs on every vehicle will decrease.

4 million kWh
This project involves a lot of planning. Daily 18 employees are engaged in the procedure. The public transport company expects to save 5% of its annual energy consumption that totals 80 million kWh. This means saving 4 million kWh a year.