BlueBattery: Austria’s biggest power plant battery in operation


From the Danube power plant at Wallsee-Mitterkirchen, VERBUND supplies hydropower support for Austria’s electricity grid in fractions of a second.

VERBUND put Austria’s first large battery into operation today in the presence of provincial governor Thomas Stelzer. Fed by hydropower, the flexibility plant at the Danube power plant Wallsee-Mitterkirchen can stabilise the electricity grid in fractions of a second.
“We are delighted about this forward-looking technology at the Wallsee-Mitterkirchen site, which is being used on this scale for the first time in Austria. Such a flexibility plant meets the energy policy objectives of the province of Upper Austria, which are laid out in the energy concept “Leading Energy Region UA 2050”,” said provincial governor Thomas Stelzer at the symbolic initial operation ceremony in the power plant.
“The goal to make Austria’s electricity supply 100% renewable in balance sheet terms by 2030 presents us with major challenges. The future of the electricity supply must be flexible because wind and sun are occasionally capricious suppliers of energy. The required reactions in fractions of a second – that’s precisely what the BlueBattery is capable of. With this innovative plant, we are setting standards for more efficiency and reliability of supply,” says Michael Strugl, Vice Chairman of the Board of VERBUND.
“We have set ourselves ambitious development targets in the area of renewable energies. These can only succeed with a modern and resilient infrastructure. Apart from the expansion of renewable energies, the construction of lines, reservoirs and flexibility capacities are key to the energy transition,” says Achim Kaspar, member of the Executive Board at VERBUND responsible for the area of generation. 

Power pack on the Danube

The works at Wallsee-Mitterkirchen began in October 2019. A large battery has been integrated into the existing Danube power plant with the objective of being able to offer the grid operator primary control power. With an output of 8 megawatt (MW) and a storage capacity of 14,200 kilowatt hours (kWh), the biggest battery in Austria by far was built at this location. 
“The energy future demands flexibility from the electricity system. With a power pack like the Blue Battery, we can balance out precisely these fluctuations in the electricity grid,” says Karl Heinz Gruber, managing director of VERBUND Hydro Power GmbH. “The Blue Battery can offer so-called ‘primary control power’ as required in fractions of a second and thus make a contribution to maintaining the reliability of supply in Austria.”
“Hydropower is mostly seen as a reliable endurance runner. In Wallsee-Mitterkirchen, we are proving that we can also jump into action on the grid. Deployments are becoming more frequent and demanding everything of the machines. With the large battery, we protect the plant and are still ready for action at all times,” says Michael Amerer, managing director of VERBUND Hydro Power GmbH. 

Grid support in seconds

The “quality” of electricity is measured by the stability of the frequency. The frequency must be 50 Hertz (Hz). Even tiny deviations pose the risk of a failure, which in the worst case can spread to become a blackout. When using the “primary control” to support the grid, energy must be drawn from the grid when frequencies in the grid are too high (stored or consumed) and additional energy fed into the grid when frequencies are too low.
Blue Battery: how it works
Five unprepossessing containers on the plant site hide around 61,000 lithium-ion battery cells, which have a total output of 10 MW (8 MW primary control plus 2 MW power for load management). If the electricity system briefly needs a primary control reserve, this is mostly made available on site by the BlueBattery, which is subsequently recharged again directly by the hydropower plant. Only in exceptional circumstances, when the frequency deviations are too strong, is a turbine of the hydropower plant additionally activated for the primary control. This unique combination of storage system and hydropower plant makes a total of 16 MW of primary control power available for the electricity system. 
The grid support provided by the supply of primary control energy is an essential part of the energy industry for ensuring a stable electricity grid in Austria and has become increasingly important in recent times. The reasons for this are the sharp rise in volatile generation units such as wind and solar energy as well as the shutdown of thermal power plants, which were used to support the grid.

 Technical specifications

 Output of battery buffer 8 MW primary control power  
 Additional 2 MW power for load management
 Primary control power of the overall system (battery and hydropower plant) 16 MW 
 Storage capacity of battery buffer 14.2 MWh (or 10 MWh at “end of life”) 
 Number of lines 
(with one converter/transformer each) 5
 Number of storage cells: 60,928
 Investment costs 7.2 million euros


Portrait Florian Seidl Florian Seidl

Spokesperson Region East

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