4. October 2023

Project PowerCharger: Storage substation successfully installed

EHIGHWAY. With the delivery and installation of the so-called storage substation, an important milestone was reached in the PowerCharger project.

In a concerted action with several companies involved, preparatory earthworks were first carried out around the block foundations that had already been set in advance. The storage substation, which weighed approx. 10 t, was then lifted into place with a mobile crane and successfully set down on the foundations. Attentive drivers will be able to recognize the storage substation at the beginning of the eHighway next to the highway in the direction of Hamburg.

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Connected to the overhead line, the storage substation does not require connection to the public power grid. The battery storage contained in the storage substation has a capacity of 120 kWh and is charged directly from the overhead line during periods of low utilization. Several modular, bidirectional DCDC converters with IGBT technology act as the link between the voltages of the battery storage and the overhead line. These enable an output power of the accumulator of up to 800 kW to supply trucks on the overhead line.

The battery storage system of the new storage substation uses the cell chemistry lithium titanate (LTO). This promises up to ten times longer cycle life than comparable battery storage systems with lithium iron phosphate (LFP). A very high continuous charge and discharge rate and low temperature sensitivity also speak in favor of using the new cell chemistry. In addition, the battery type can achieve a long service life of more than 25 years, so overall there are many important characteristics for a stationary peak load storage system.

The aim of the Kiel University of Applied Sciences is to use the storage substation to investigate the extent to which its use can contribute to relieving the public power grid. It is conceivable to relieve the load by capping power peaks occurring temporarily during operation of the overhead line system (peak shaving) by having the storage substation support the existing substations. The storage substation represents another opportunity with regard to a future expansion of the overhead line infrastructure. With storage substations, the distances between substations and grid connection points are increased, thus reducing construction costs .