A 30 MW/60 MWh BESS called Eskilstuna Power Reserve is to begin commercial operation in the SE3 bidding zone of Sweden in November 2026. The plant is the first energy storage investment of Monsson in the country, and it uses the proprietary technology of the Romanian company, which has reported that commissioning has been finished.
Storage size: 30 MW/60 MWh
Discharge duration: 2 hours
Commercial operation: November 2026
Bidding zone: SE3
Switching time: Under 3 seconds
EU-made components: Over 95%
Technology: Monsson proprietary
Monsson, a Romania-based renewable energy company, has launched its first BESS in Sweden, and it has named the plant Eskilstuna Power Reserve. The plant has been sized at 30 MW and 60 MWh, so that it can discharge for two hours. Monsson made the announcement on 27 October 2026, and it expects commercial operation to begin in November.
The plant is meant to give the grid flexibility and stability in the SE3 bidding zone of Sweden. It needs less than three seconds to switch between charging and discharging, so it is able to follow sudden changes in generation and consumption. It uses the proprietary technology of Monsson, and Daniel Ioniță, the Ambassador of Romania to Sweden, has said that over 95% of its components were made in EU member states. Commissioning began in September 2026, and the company has since reported that the work has been finished.
Eskilstuna Power Reserve represents an important step in Monsson's expansion into the Nordic market. Through this 30 MW / 60 MWh project, we are bringing our energy storage technology and expertise to Sweden, with the aim of contributing to grid flexibility and stability. Commissioning activities are finished, and commercial operation is scheduled for November 2026. Our team in Sweden, together with our colleagues in Romania, is ready to provide these flexibility services both locally and across Europe.Sebastian Enache, Head of Strategy & M&A at Monsson
The launch event in Eskilstuna on 22 October brought together representatives of the Swedish energy industry, grid operators, authorities and the business community, and they were given guided tours of the facility. The plant has also drawn interest from the city itself, which has set a goal of becoming fossil-free and climate positive by 2045. Daniel Lindekrans Henriksson, an Energy Strategist of Eskilstuna Municipality, has described the plant as a new capability for Eskilstuna and Strängnäs, and has named the new local flexibility market of ESEM as one way of realising its potential.
The plant will join a Swedish market in which several large BESS have been reported in 2026. Centrica started two 40 MW BESS in Borlänge in April, and Sungrow powered the 70 MW/160 MWh plant of Delta Capacity, which was then the largest operational BESS of the Nordic region, in July. In the same month, Trina Storage was chosen to supply 209 MWh for the Fageråsen project of OX2.