CellCube battery storage at the Nagel-Group site in Bochum ensures sustainability, cost-effectiveness and process reliability

Environmental awareness is an integral part of the Nagel-Group’s corporate ethics. The fact that this fundamental attitude can also have a positive influence on the achievement of economic goals is demonstrated at the Nagel-Group’s location in Bochum. In order to make more extensive use of the electricity produced by the largest rooftop photovoltaic system in the Ruhr area, an important element was added to the on-site infrastructure: vanadium.

Since 2020, the roofs of the branch have been home to a PV system that is still unique in the region in terms of size and performance. Around 8,000 modules cover an area of 13,000 square metres. For comparison, the lawn of Bochum’s Ruhrstadion is just over half that size at 7,000 square metres. The 2 million kWh produced per year would be enough to supply around 650 single-family homes or 1,500 single apartments with electricity.

However, only part of this energy has been used on site so far. While the cooling system and the fully electric trucks were able to draw on the energy when the sun was shining, at night or during peak loads, the site continued to rely heavily on external sources. At the same time, when weather conditions were ideal, more electricity was produced than could be consumed. The average self-consumption rate was around 60 per cent, with the rest having to be fed into the grid.

The CellCube redox flow battery storage system installed at the Bochum site, in combination with the new energy management system, enables the Nagel-Group to use all of the solar power generated on site for its own purposes, thereby increasing sustainability, cost-effectiveness and process reliability. Photo: Nagel-Group

The rate of owner-occupancy is growing, the carbon footprint is shrinking

To ensure greater autonomy, a battery storage system was to be installed at the site. The challenge here was that conventional lithium-ion batteries are not optimised for parallel charging and discharging processes in many applications. This is a major disadvantage in day-to-day logistics operations. Furthermore, they are anything but environmentally friendly due to the resource-intensive extraction of raw materials and high energy consumption during production. After extensive research and comprehensive discussions, the perfect cooperation partner for this project was found in Austria.

The company CellCube Energy Storage has been working on a new, powerful energy storage solution just outside Vienna for more than 25 years. The function of these so-called redox flow batteries is easy to explain: electrolytes are stored in two separate tanks as a storage medium. They are pumped through a cell in separate circuits, where the stored energy is then provided as electrical energy as needed. ‘The vanadium electrolyte we use is recycled from by-products of the steel industry. It is non-flammable, reusable and does not contain any rare earths, which represents a significant environmental advantage over conventional battery systems,’ says Christoph Stelzer, COO of CellCube Energy Storage GmbH, explaining the benefits of vanadium flow technology.

There are other important advantages to this setup. The storage capacity depends on the size of the tanks, while the performance is determined by the size of the cell. This means that energy and performance requirements can be scaled independently of each other and precisely adapted to the respective requirements. The energy can be stored flexibly and provided in a targeted manner over a discharge period of 4 to more than 24 hours. With a lifespan of around 30 years and more than 30,000 charging cycles, the storage system is ideal for daily use at the Nagel-Group site in Bochum.

Forward planning for maximum efficiency

Thanks to the new storage facility, which has been part of the infrastructure since July 2025, the goal of complete self-consumption of locally produced electricity has come a big step closer. One challenge remained: ‘The battery storage system allows us to control electricity consumption and supply even more efficiently,’ explains Sven Budde, Technical Manager of the Nagel-Group at the Bochum site. ‘The sun doesn’t always shine over the Ruhr region and we sometimes have significant load fluctuations. To prevent peaks, we need to be able to plan ahead,’ Budde continues. Together with CellCube and Solar-E-Technik Hamm GmbH, an application was therefore developed that makes precisely this possible.

After an intensive development phase, the new energy management system underwent its first tests in December 2025. And after just a short period of fine-tuning, it became clear that the project was a complete success. Thanks to the newly gained predictability, the engineers achieved their declared goal of 100 per cent self-consumption of the green electricity produced on site. This is a major success for the environment, which also benefits the company. Another important aspect is that in extreme cases, the storage facility can function as an emergency generator and compensate for power failures. A safety net that can be invaluable in food logistics.

A project with exemplary character

‘Logistics is an energy-intensive industry. The sustainable use of electricity is not only important from an environmental perspective, but also from a business perspective. Thanks to the new redox flow battery from CellCube, the Nagel-Group has taken a major step towards its strategic goal of sustainable logistics,’ explains André Pleines, Executive Director Real Estate at the Nagel-Group.

It is therefore logical that the successful completion of this project will lead to further measures. On the one hand, the PV roof system in Bochum is currently being expanded, which will increase the maximum output by another 1,200 kW. On the other hand, the successful model from the Ruhr area is also to be implemented at other locations in the future. The starting signal for projects at the branches in Hamburg and Schweitenkirchen has already been given. This development can certainly be seen as a signal. After all, sustainability and economic efficiency do not have to be mutually exclusive. In many cases, they are even mutually dependent.