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Energy bank to strengthen power supply of Rotterdam tram

Rotterdam’s public transport operator RET and consortium Energieverbinders (Dutch for Energy Connectors) have joined forces for a pilot that will lead to the realisation of the first Energy bank for the tram. The energy bank must be operational in December. The Energy bank will strengthen the power supply at the Posthumalaan turn loop, enabling RET to use the loop as a transfer point for passenger flows to Rotterdam Central Station and for soccer events.

When the Energy bank proves to be operating according to plan, the way will be open to solutions for more bottlenecks due to energy network congestion. The innovative power of Europe’s Rail Joint Undertaking, part of the EU’s Horizon Europe Programme (2020-2027) is used for the pilot.

RET built a tram turn loop at the Posthumalaan in Rotterdam a couple of years ago. This loop is currently used for calamities only. Once the power supply has been strengthened, the turn loop will also be suitable for tram traffic between the Kuip stadion and Wilhelminaplein metro station. Normally, an additional substation is necessary to strengthen the power supply, but that is costly, time consuming and wastes a lot of space.

Unplugged substation

The Energy bank is a good alternative for a substation. The concept was developed by consortium Energieverbinders (Dutch for Energy Connectors), consisting of Strukton Rail, Strukton Power and Hedgehog Applications. With modern technology and energy storage facilities, they developed a compact ‘unplugged substation’.

The Energy bank is identical to a classical rectifier station in terms of characteristics, but it is not connected to the electricity grid. The Energy bank charges itself through the catenary system of the tram at moments when no tram is passing (both during the day and at night) and makes sure that the energy is charged when electricity rates are low or even negative. This high-tech system serves as a fully operational extension of a classical power supply system with rectifier stations.

The Energy bank is a good alternative for a substationo. It charges through the catenary when no trams are running,

World first

The concept of the Energy bank only consisted on paper, until now. The Energy bank in Rotterdam is therefore a world first. Realising the Energy bank in practice will lead to two positive results:

  1. The Posthumalaan turn loop will have a full power supply, enabling regular use and use for events
  2. Practice-based insights will be gained as to applicability of the Energy bank as an alternative for the additional rectifier stations needed for planned improvements of the Rotterdam tram network to enable highly frequent traffic with faster trams


Characteristics of the Energy bank include:

  • It is a high-tech extension of the power supply with rectifier stations, and is therefore not affected by energy network congestion problems
  • It is fed through the catenary system, so no connection to the power grid is required
  • It weighs approximately 8,000-9,000 kg, so no foundation is required
  • It is small: 1.8 m deep) x 2.5 m high x ca 3 m long (depending on the power to be supplied) and can even be place on a platform
  • It charges energy when electricity rates are low or negative
  • It is replaceable. When required, the Energy bank can easily be moved to a different place, to e.g. strengthen the power supply in case of detour routes
  • The price is lower than the price of a rectifier station. It has lower technical installation costs and no strengthening of the catenary system is required

Photo: Victor through Unsplash


This innovation contributes to Social Development Goal (SDG) 7 -Affordable and clean energy. Our current reliance on fossil fuels is unsustainable and harmful to the planet, which is why we have to change the way we produce and consume energy. Implementing these new energy solutions as fast as possible is essential to counter climate change, one of the biggest threats to our own survival. We actively wish to contribute to the United Nation’s SDGs, focusing on SDG 7, 8, 9, 12, 13, 15 en 17.

Sustainability at Strukton

About Energieverbinders

Energieverbinders (Energy connectors) is a consortium of Strukton Rail Nederland, Strukton Power and Hedgehog Applications. They have joined forces to solve problems of energy network congestion with modern technology and energystorage facilities and, in so doing, accelerate the energy transition.

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