ENGIE

Regulatory Filings • Dec 15, 2025

Press release December 15 th , 2025

ENGIE strengthens the resilience of the Belgian electricity system with new flexible capacities

• ENGIE recently announced that the new Flémalle combined-cycle gas turbine plant (875 MW) is available for the grid. This is a major asset for Belgium's electricity security of supply.
• This success adds to the early commissioning of the Vilvoorde battery storage system (200 MW / 800 MWh), the award of a new battery project in Drogenbos (80 MW / 320 MWh), and the ongoing modernization of the Coo pumped-storage plant.
• These projects reflect the Group's ambition to combine renewable generation with flexibility to deliver a reliable, low-carbon power system.

ENGIE is reaching major milestones for Belgium's electricity security of supply—one of the Group's historic markets—by commissioning and developing strategic infrastructures that enhance grid resilience and support 24/7 renewable energy integration.

Flémalle: a state-of-the-art gas-steam power plant

Selected during the first auction of the Belgian Capacity Remuneration Mechanism (CRM) in 2021, the Flémalle combined-cycle gas turbine plant (875 MW) is now available for the grid. Designed to keep emissions as low as possible and ultimately become CO₂-neutral, it will achieve an efficiency above 63%, making it one of the most efficient plants in the world. Thanks to its fast start-ups and modulation capability, the facility provides high flexibility to respond to demand fluctuations and supply more than one million households.

Vilvoorde: one of the largest battery storage projects in Europe

ENGIE has commissioned, two months ahead of schedule, its Battery Energy Storage System (BESS) in Vilvoorde, one of the largest in Europe. With a capacity of 200 MW / 800 MWh, BESS Vilvoorde can store and deliver for four hours the equivalent of the daily electricity consumption of nearly 100,000 households. An extension to 300 MW / 1,200 MWh is under study. With Vilvoorde, Kallo and Drogenbos, ENGIE will have 380 MW / 1.5 GWh of battery storage capacity installed in Belgium by 2027.

Coo: modernizing a historic infrastructure

A cornerstone of the Belgian electricity system for over fifty years, the Coo pumped-storage plant has been undergoing an extensive expansion and modernization program since 2021. Following the raising of the upper reservoir dams, works are continuing to increase capacity by

79 MW / 450 MWh, reaching a total output of 1.16 GW / 6.45 GWh, while extending the lifetime of the facility.

A European ambition

Beyond Belgium, ENGIE is accelerating the development of flexible assets across Europe. With 531 MW of BESS capacity in operation and under construction in Europe as of June 2025, the Group has since announced the construction of two battery projects in Romania (85 MW / 170 MWh) and the acquisition in Italy of three projects totalling 250 MW / 1 GWh. These initiatives support ENGIE's global objective of reaching 95 GW of renewable and storage capacity by 2030.

"Flexibility is at the heart of the energy system. It plays a crucial role in maximizing the full potential of renewable energy around the clock and ensuring grid stability at all times. In Belgium and elsewhere, our strategy is built on complementarity: renewable generation, storage, and dispatchable assets to deliver a reliable, low-carbon, and competitive electricity system," said Paulo Almirante, ENGIE Senior Executive Vice President in charge of Renewable and Flexible Power

About ENGIE

ENGIE is a major player in the energy transition, whose purpose is to accelerate the transition towards a carbon-neutral economy. With 98,000 employees in 30 countries, the Group covers the entire energy value chain, from production to infrastructures and sales. ENGIE combines complementary activities: renewable electricity and green gas production, flexibility assets (notably batteries), gas and electricity transmission and distribution networks, local energy infrastructures (heating and cooling networks) and the supply of energy to individuals, local authorities and businesses. Every year, ENGIE invests more than €10 billion to drive forward the energy transition and achieve its net-zero carbon goal by 2045.

Turnover in 2024: €73.8 billion. The Group is listed on the Paris and Brussels stock exchanges (ENGI) and is represented in the main financial indices (CAC 40, Euronext 100, FTSE Euro 100, MSCI Europe) and nonfinancial indices (DJSI World, Euronext Vigeo Eiris - Europe 120 / France 20, MSCI EMU ESG screened, MSCI EUROPE ESG Universal Select, Stoxx Europe 600 ESG-X).

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