Steag: Large-scale battery systems in operation

By 2025, 40-45 per cent of Germany’s electricity demand should be met by renewable energies. To offset the volatility of wind and solar energy, power storage systems such as large batteries will be needed. Temporary fluctuations in demand are currently balanced almost exclusively by conventional power plants. STEAG plans to demonstrate that this is also possible using battery systems. It is currently constructing six large-scale batteries with a total capacity of 90 megawatts, half of them in North Rhine-Westphalia.

Engine for progress:

  • provision of 90 megawatts of primary balancing power, half of which in NRW
  • largest battery storage project in Germany
  • level of investment: €100 million
  • on a purely commercial basis, no grant funding
  • reduction in CO2 emissions

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Photo: STEAG

The three battery power plants planned in NRW are being built physically separate from the existing conventional power plants, but still in close proximity to them. They are being constructed on the power plant sites in Herne, Lünen and Duisburg-Walsum. “This way we can take advantage of synergies in the infrastructure”, explains Christian Karalis, large-scale battery systems project manager at STEAG. The storage units are lithium-ion batteries. They are fully automated and can react within seconds, thus providing important primary balancing power. As a prerequisite of participation in the primary balancing power market, a minimum of 30 minutes’ supply must be guaranteed. The advantage over conventional power plants is that large-scale battery systems providing primary balancing power do not need to produce a minimum load, thus saving fossil fuels and reducing CO2 emissions. On a weekly basis, the transmission system operator tenders for primary balancing power , which serves to stabilise the power grid for short periods. This also means that conventional power plants can still be used efficiently when energy is required at times when no electricity is being produced from renewable sources.

100-million-euro investment

STEAG invested 100 million euros in this major project and did not request any outside funding. All of the planned installations should be in operation by early 2017, at the latest. In addition to the three storage systems in North Rhine-Westphalia, there will be three more in the Saarland. Together they will provide 90 megawatts of capacity. It is the largest storage project in Germany based on lithium-ion technology. Previous storage projects were generally funded research projects, whereas these storage systems are being constructed without research money and are intended to be competitive on the market.

Storage system experience from LESSY research project

STEAG has been gaining experience on the subject of storage since 2009 with its previous project, LESSY. This project involved installing a large-scale battery with 1 megawatt of capacity at Völklingen in 2014 and launching it onto the balancing power market. In doing so, LESSY became one of the first Li-ion battery storage systems in Germany to be approved for grid stabilisation. The knowledge STEAG gained in this project is now coming in useful for the market launch.


Photo: Steag

“With large-scale batteries, not only is it possible to supply primary balancing power, but other system services for grid operators can also be provided in the future. For this purpose, appropriate markets must be created, as with balancing power. In this way, strictly separating the business of grid operation from that of producing or providing system services, will also be an important way of supplying energy efficiently in the future.”

Christian Karalis, Project Manager at STEAG

Partners and sponsors

  • STEAG GmbH