Important launch from Merus Power: The first grid-forming battery energy storage system in the Nordics

YLÖJÄRVI, Finland, Nov. 20, 2025 /PRNewswire/ -- Merus Power has brought online the first grid-forming (GFM) battery energy storage system (BESS) in the Nordic countries for its Swiss customer, Alpiq. The 30 MW / 36 MWh energy storage system commissioned in Valkeakoski, Finland, meets the requirements set by Fingrid, Finland's Transmission System Operator (TSO), for large-scale grid-forming energy storages. The functionality of the technology has been verified and approved by Fingrid through simulations and demanding field tests.

Grid-forming BESS solutions are capable of independently supporting the power grid during disturbances and fault situations. Merus Power's energy storage strengthens grid stability and enables a more seamless integration of renewable energy sources into the power system.

New technology revolutionizes the role of energy storage

Unlike traditional grid-following power electronics solutions, the grid-forming Battery Energy Storage System (BESS) delivered by Merus Power can independently maintain voltage and frequency, improve grid stiffness, and support the power system during disturbances. This capability enables, for example, the creation of a grid after a blackout and makes the energy storage an active enabler of grid stability.

Grid-forming means that an energy storage system or another power source does not merely follow an existing grid but can independently establish and maintain grid voltage and frequency. This allows it to serve as a foundation for grid stability even in fault situations. Units operating with traditional grid-following control, such as wind turbines, require a sufficient amount of grid-forming capacity to function stably. Therefore, grid-forming energy storage systems play a crucial role in enabling further growth in renewable energy generation.

The project carries historical significance, as Fingrid published its first requirements for grid-forming functionality in type D and C energy storages only in the summer of 2023. Merus Power successfully developed the technology and brought it into commercial use in just two years. The facility has passed the verification process, which includes both extensive modeling requirements and demanding field tests, demonstrating its reliability and capability to strengthen grid stability.

"We are proud that Merus Power is the first in the Nordics to bring online a grid-forming battery energy storage system. This achievement demonstrates the top-level expertise of Finnish product development and our ability to respond quickly and reliably to the new requirements of the green transition. Security of supply and cybersecurity are also key values in our operations, as energy storage systems are part of critical infrastructure. This project strengthens our position as a significant European energy storage provider and supports our strategic goal of building a more sustainable and secure energy system," says Kari Tuomala, CEO of Merus Power.

"This first grid-forming energy storage system developed in the Nordics is an important step towards an even cleaner and more flexible electricity system. It is great to see new technological solutions like this being introduced to the power system to ensure its reliable operation and enable the growth of renewable energy in the grid. Fingrid works closely with technology developers and looks openly towards the future," says Asta Sihvonen-Punkka, CEO of Fingrid Oy.

Merus Power and Alpiq behind the success

In this project, Merus Power served as the developer, supplier, and EPC (Engineering, Procurement, and Construction) contractor, overseeing the entire process from permitting and design to manufacturing, delivery, and commissioning. Merus Power's energy storage systems are based on in-house developed and manufactured technology. A strong focus on grid-forming development further enhances our solutions and strengthens our position as a technology leader.

Commissioned by the Swiss energy company Alpiq, the project is also their first grid-forming energy storage system. The project strengthens Alpiq's position as a provider of flexible energy solutions in the European power market and supports the growth of renewable energy.

"This first grid-forming energy storage system is a major milestone for us and an excellent example of how collaboration and innovation can accelerate the green transition. At Alpiq, we proudly bring our expertise to flexible solutions that support a cleaner energy future. Despite the demanding product development process, the system was delivered ahead of schedule, which is a remarkable achievement from Merus Power. It also reflects the strong commitment of everyone involved," says Lukas Gresnigt, Head of International and member of the Alpiq Executive Board.

Security of supply and cybersecurity as part of critical infrastructure

Merus Power's battery energy storage systems ensure a high level of security of supply, even in global crisis situations, as the company operates in Europe and all manufacturing takes place in Finland. Cybersecurity is also an essential part of every solution, since energy storage systems are part of critical infrastructure. All power electronics and grid connection software are fully developed in-house by Merus Power.

Merus Power is today recognized as one of the leading energy storage providers in the Nordics. This project is not only a commercial success but also a step towards a new era of energy storage, demonstrating how BESS can enhance grid stability and security of supply while enabling an even greater integration of renewable energy.

Merus Power in brief

Merus Power is a technology company driving the sustainable energy transition. We design and produce innovative electrical engineering solutions such as energy storages and power quality solutions, and services for the needs of renewable energy and industry. Through our scalable technology, we facilitate the growth of renewable energy in the electricity grids and improve the energy efficiency of society. We are a domestic specialist in innovative electrical engineering and operate in global and high-growth markets. Our personnel represent internationally renowned engineering expertise. Our net sales in 2024 was EUR 35.8 million and our stock's trading symbol on the Nasdaq First North Growth Market Finland is MERUS.

Photo: https://mma.prnewswire.com/media/2818527/Merus_Power_GFM_ESS.jpg

For more information:

Kari Tuomala
CEO
kari.tuomala@meruspower.com
+358 20 735 4320 

Jonna Kannosto
Marketing and Communications Director
jonna.kannosto@meruspower.com
+358 44 357 8320