RRKW RoterKnopfEurope’s biggest battery storage system enters service
Joint Energiequelle and ENERCON project / 10MW load-balancing capacity

Feldheim, 7 September 2015 -  In the presence of the State of Brandenburg Minister for the Economy and Energy, Albrecht Gerber, the managing directors of Enercon GmbH and Energiequelle GmbH, Hans-Dieter Kettwig and Michael Raschemann, brought Europe’s biggest battery storage system online. Offering 10 megawatts in power capacity, this large battery system will help the transmission grid operator to maintain its 50 Hertz grid frequency.
‘Appropriate power storage systems are a key requirement for safeguarding future power supplies centred on wind energy. With large-scale battery storage units such as the one here in Feldheim, we can already play an important role in stabilising the grid in an efficient and economical manner’, says Michael Raschemann.

‘Thanks to their overwhelming success, renewables have meanwhile achieved the status of essential power stations’, commented Hans-Dieter Kettwig. ‘However, if renewables are to assume greater responsibility for power supplies, with the aid of storage systems, and replace reserve power stations that burn fossil fuels and harm the climate, then policymakers must also step up to the mark – they should provide frameworks that offer operators incentives to invest in innovative storage technologies, so that we can take the decentralised energy transition another step forwards.’
Albrecht Gerber proclaimed that, ‘From today onwards, a new chapter in the history of power storage is being written. This battery system is not only the biggest of its kind in Germany, but also a milestone in the systemic integration of renewable energies. At national level, we have to focus more strongly on grid expansion, systemic integration and acceptance.’
The 10-megawatt lithium-ion battery storage system – officially called the Feldheim Regional Regulating Power Station (RRKW) – is a joint project implemented by Energiequelle GmbH, the Zossen-based wind farm planners, and Enercon AG, the Aurich-based manufacturer of wind turbines. The battery will provide load-balancing power for the transmission grid. Load-balancing power is needed in order to balance out temporary variations in grid frequency. The RRKW can relieve the grid when there is an oversupply of electricity and, vice versa, can deliver power within seconds and thus stabilise the grid.
The battery bank consists of 3360 storage modules made by Korean manufacturer LG Chem; the sophisticated control technology was developed by ENERCON. The storage battery is marketed by Vattenfall on the market for load-balancing power.
The RRKW involved a total investment of around 12.8 million Euro. The regional government for the State of Brandenburg supported the project with around five million Euro in grant assistance from its RENplus programme. The grant is a combination of financial assistance from the European Regional Development Fund (ERDF) and funds from the State of Brandenburg.
The building that houses the storage system was also a source of surprise and astonishment for the more than a hundred guests at the inauguration ceremony.  The reason was that three façades of the 17 m by 30 m edifice had been decorated by graffiti artist. The modern work of art was designed by school students now in Form 9L at the ‘Evangelisches Gymnasium Hermannswerder’ (a Potsdam grammar school), who won the ‘Physics Meets Art’ competition organised by Energiequelle. The mural symbolises the interplay between wind turbines and power storage media.