Wärtsilä Builds Two-Hour Large-Scale Battery Storage System for Grid Stabilization in Belgium

Helsinki (Finland) - The market for large-scale battery storage systems in Europe is currently gaining significant momentum. The Finnish technology group Wärtsilä has started construction of a two-hour battery energy storage system with a capacity of 50 megawatts and an energy storage capacity of 100 megawatt-hours in central-eastern Belgium.

The client is the Belgian company Gramme Storage 1, which serves as the legal entity behind the energy storage project. The aim of the Gramme 1 project is to increase the flexibility of Belgium’s power system and support the transition to renewable energy. Completion is scheduled for the second quarter of 2027. The order was already booked in the second quarter of 2025.

“This project with Wärtsilä underscores our commitment to dependable, flexible energy in Belgium,” said Guillaume Poncelet, Managing Director of Kallima Energies, the project developer. He emphasized that battery storage systems are playing an increasingly central role in grid stabilization.

Gramme 1 is Wärtsilä’s first energy storage project to participate in Belgium’s Capacity Remuneration Mechanism (CRM). This mechanism compensates assets that provide critical grid services such as frequency and voltage support in order to enhance security of supply and grid resilience.

“Wärtsilä’s advanced technology will enable the site to provide critical ancillary services that support a resilient, future-ready grid,” said David Hebert, Vice President Global Sales Management at Wärtsilä Energy Storage.

The facility will use the Gridsolve™ Quantum2 energy storage system as well as the GEMS control and optimization software. Wärtsilä is delivering the project under an engineered equipment delivery contract, complemented by a long-term service agreement. With Gramme 1, Wärtsilä’s energy storage portfolio in Europe will increase to more than 2.7 GWh of storage capacity, according to the company.

The project highlights the growing importance of large-scale battery storage systems for the stability of European power grids and demonstrates the ongoing shift toward renewable energy, which is being actively driven by technology and infrastructure companies such as Wärtsilä, the company emphasized.

Source: IWR Online, 17 Feb 2026