SWB chooses new battery energy storage concept

This service is provided to grid-operators to stabilise the grid and is increasingly needed as renewable sources are integrated.

In this hybrid system, energy is stored both in a battery system and an electrical heating system which are connected to the power converter. These are controlled as one unit to provide the required bidirectional power flow (to or from the grid) to balance the frequency and ultimately to ensure the stabilisation of the grid.

AEG Power Solutions designed this concept based on its power electronic expertise. The patent is currently under review. The company has engineered the complete solution and will provide swb with 24 storage converters integrated in ISO-metal sheet containers together with an hybrid storage option, low-voltage distribution cabinets, auxiliary power supply as well as medium voltage transformers and the heating system in separate enclosures.

This hybrid storage system significantly reduces the cost of primary-frequency power operation. First, the required battery capacity is significantly smaller compared to a conventional battery-only system (approx. 50%), and the second source of storage (heating) is considerably less expensive. Additionally, power electronics and all components for grid connection (e.g. transformer) are used twice by utilising both storage systems which contributes to minimising installation hardware costs.

This improves the pay back for the operators of the system and helps to reduce grid fees which is of general public interest.

“Our team has worked on this solution since 2015", explained Jörg Liedloff, CTO at AEG Power Solutions. "We are convinced that this approach is a very cost effective and highly reliable one to support grid-stabilisation requirements. It’s a great achievement for us to partner and implement it together with swb which is in charge of the global control system. We strongly believe that the market for such solutions is maturing now and will offer us further opportunities.”

“At swb we believe we can develop a sustainable and renewable energy supply," said Jens-Uwe Freitag, Managing Director at swb Erzeugung AG & Co. KG. "The hybrid system concept developed by AEG PS is innovative and a perfect match for SWB as we supply electrical and thermal energy already today. We cooperated tightly with the AEG PS team. This solution will contribute to position us strongly in our market.”