The first phase of a 200 MW/800 MWh lithium-ion battery storage facility has come online in Belgium, signaling a new model for four-hour grid-scale batteries.
A four-hour duration battery energy storage system (BESS) is on track to become the largest of its kind on the European mainland. The first phase of the Vilvoorde project is grid-connected and operational outside Brussels, Belgium. Sungrow and Engie developed the system, which will serve up to 96,000 households at full capacity.
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Tour the Vilvoorde Battery Park. Video used courtesy of Sungrow
Developed on a former gas plant site, Vilvoorde represents a confluence of technical pragmatism and policy alignment. The full system, rated at 200 MW with 800 MWh of energy capacity, will support Belgium’s resource adequacy framework through a 15-year capacity agreement with the transmission system operator, Elia. It also introduces a tightly integrated containerized architecture based on Sungrow’s PowerTitan platform, an AC-coupled, liquid-cooled BESS solution.
The Vilvoorde BESS. Image used courtesy of Sungrow
A Four-Hour Battery Engineered for the Grid
While large-format storage batteries are now routine in the U.K. and parts of the U.S., mainland Europe has lagged in bringing multi-hundred-megawatt-hour projects to market. Belgium’s Capacity Remuneration Mechanism (CRM), introduced to replace nuclear capacity and bolster grid reserves, has begun to change that equation.
Through this mechanism, Vilvoorde secured its 15-year capacity contract, creating a stable investment profile for Engie to pursue a long-duration system with bankable returns. The four-hour configuration allows the battery to respond to peak demand events and reserve shortfalls, particularly during low renewable energy output windows common in winter.
Sungrow’s AC block design fully builds out the site, rather than centralizing inverters or separating PCS hardware from battery racks. Each 20-foot container integrates 5 MWh of lithium iron phosphate (LFP) battery storage with a 2.5 MW inverter, liquid-cooling loops, thermal safety controls, and digital monitoring. A total of 320 units will populate the final buildout, deployed across a 3.5-hectare footprint with a uniform design that streamlines installation and reduces interconnection complexity.
Thermal Uniformity at Scale
With a four-hour duration, thermal management becomes a defining engineering constraint, especially in tightly packed systems. Sungrow’s PowerTitan platform addresses this through an integrated liquid cooling system that circulates coolant directly across battery cell arrays, rather than relying on air-based HVAC systems that tend to produce wider thermal gradients. More uniform temperatures translate directly to lower degradation rates, improved round-trip efficiency, and tighter safety tolerances under frequent cycling. This is particularly important in Belgium’s temperate but variable climate, where seasonal fluctuations in temperature and humidity can create complex thermal profiles for passive systems.
The PowerTitan 2.0 Liquid Cooling storage system. Image used courtesy of Sungrow
The AC block design also enables electrical simplicity. By pairing each battery array with its own power conversion system in the same enclosure, Sungrow avoids the DC cabling complexity that plagues larger centralized designs. Each block connects directly to the medium-voltage ring, allowing Engie to optimize layouts for phase balancing and maintenance segmentation. The design allows for partial operation during installation or outage, enabling Engie to bring 100 MW of power capacity online while the second phase is still under construction.
While air-cooled designs remain dominant at smaller scales, the shift to liquid cooling is increasingly common in long-duration systems where cycle life and OPEX matter more than upfront CAPEX. In this context, Vilvoorde’s design represents a middle path: not experimental but optimized, favoring known chemistries and proven integration strategies while deploying them in a modular fashion that anticipates expansion and regulatory scrutiny.
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Look inside the PowerTitan. Video used courtesy of Sungrow
Beyond the hardware, Vilvoorde’s structure enables it to reach commercial scale. The capacity contract with Elia provides guaranteed availability payments, effectively underwriting the project’s core economics regardless of real-time energy pricing or arbitrage margins. This allows the battery to participate more confidently in ancillary services markets, including primary and secondary frequency control, voltage support, and potentially congestion management in the Brussels load pocket.
The second phase of the project, bringing the total capacity to 200 MW/800 MWh, is expected to be operational by early 2026. As it scales, the Vilvoorde BESS will serve as a template for how to build large-scale energy storage in dense, grid-constrained environments.
Keywords: battery energy storage systems, lithium-ion batteries, grid stability, liquid cooling, thermal management, renewable energy, Sungrow, Engie
