GIGA Storage has started construction on Green Turtle, a 700 MW / 2.8 GWh battery energy storage project in Dilsen-Stokkem, Belgium. The project is designed as a four-hour grid battery and is set to become Belgium's largest storage facility when it reaches commissioning, targeted for the end of March 2028. The build turns a former zinc factory site in Limburg into a new flexibility node for Belgium's high-voltage grid. It also gives Europe another large example of how battery projects are moving from development pipeline into financed construction. AI-generated image Green Turtle is planned as a 700 MW, four-hour storage asset on a former industrial site in Belgian Limburg. The Project in Numbers Green Turtle will use 640 Tesla Megapack 3 units based on lithium iron phosphate chemistry. GIGA Storage says Tesla is acting as the full engineering, procurement, and construction partner, with long-term maintenance also included. Civil works are being carried out by Stadsbader Contractors on Tesla's behalf. The site plan includes 188 medium-voltage transformers and four high-voltage transformers. Those details matter because a battery this large is not only a collection of containers. It is a grid asset that needs transformer capacity, control systems, protection equipment, civil foundations, thermal management, and a transmission interconnection that can move hundreds of megawatts in either direction. 700 MW Power Rating 2.8 GWh Storage Capacity 640 Megapack 3 Units 2028 Target Commissioning At peak output, the battery could supply electricity equivalent to the daily use of about 385,000 households, according to GIGA Storage's project materials. That comparison is not a dispatch plan, but it helps size the asset. A four-hour battery at this scale can absorb surplus renewable generation, discharge into evening demand, support frequency regulation, and reduce congestion around the transmission system. Why the Location Matters Green Turtle is being built on roughly 12 hectares at the Rotem industrial estate, the former site of the Societe Anonyme de Rothem zinc factory. That brownfield setting gives the project an industrial land use that fits heavy electrical infrastructure better than a greenfield site would. It also places the battery near the grid equipment it needs to operate at scale. AI-generated image The project sits next to planned Elia high-voltage infrastructure tied to Belgium's 380 kV network. The site is positioned near Elia's future high-voltage substation and the 380 kV Van Eyck-Gramme line. Elia is building a new substation for the connection. That direct link to the high-voltage network is central to the project. Large batteries earn their value by being in the right electrical place, not only by having enough cells. A 2.8 GWh battery far from constraints would be less useful than one tied into a busy transmission corridor. Belgium's grid is adding more variable renewable power while also managing cross-border flows, nuclear retirement questions, electrification, and industrial demand. A four-hour battery can help by responding quickly when frequency moves, charging when power is abundant, and discharging when the system needs fast capacity. It will not replace every form of firm generation or long-duration storage, but it can reduce the number of hours when the grid has to lean on fossil peakers for short balancing needs. Why It Stands Out Green Turtle combines project finance, a high-voltage connection, a brownfield industrial site, and Tesla Megapack 3 hardware in one of Europe's largest battery builds. The size is headline grabbing, but the grid location is what makes the project operationally important. A Bank-Financed European Battery The financing is as important as the technology. GIGA Storage reached financial close in July on a total investment of about 700 million euros. The debt package is about 450 million euros from a 10-bank consortium that includes ABN AMRO, asr, Belfius, Hamburg Commercial Bank, ING, Rabobank, Santander, SMBC, Triodos Bank, and Triodos Investment Management. InfraVia Capital Partners, GIGA Storage's majority owner, is providing the remaining equity. AI-generated image The 700 million euro investment shows that large European batteries can attract multi-bank project debt when interconnection and revenue structure are credible. Large BESS financing still depends on revenue confidence. Batteries can sell balancing services, trade power across price spreads, reduce congestion, and contract with grid or market parties. Lenders have to believe those revenue streams can support debt service through changing market rules. Green Turtle's financing suggests that, at least for well-sited projects with credible sponsors, European banks are becoming more comfortable with utility-scale storage risk. That confidence is not automatic across the market. Many European battery projects remain stuck behind connection queues, uncertain capacity payments, permitting friction, or merchant revenue volatility. Green Turtle does not erase those issues. It does show what a project looks like when several pieces line up: land, grid proximity, mature hardware, a large sponsor, and a bank group willing to fund construction. What the Megapack 3 Choice Says The selection of Tesla Megapack 3 puts Green Turtle inside a broader trend toward standardized grid battery blocks. Developers want systems that can be financed, insured, permitted, operated, and maintained with known performance assumptions. LFP chemistry is now common in stationary storage because it offers strong cycle life, lower thermal runaway risk than nickel-rich chemistries, and no cobalt in the cell chemistry. AI-generated image LFP systems dominate new grid storage because cycle life, safety, and cost are more important than maximum energy density. For stationary storage, the tradeoff is different from electric vehicles. Weight and pack volume matter less. Safety, warranty life, installation speed, operating software, and grid-code compliance matter more. A four-hour system also needs enough energy capacity to cover longer price and reliability windows than a one-hour frequency response battery would. Green Turtle's construction start is therefore more than a local Belgian milestone. It is another data point in Europe's shift from pilot-scale storage to transmission-scale assets. The continent needs batteries that can be financed like infrastructure and operated like grid equipment. Belgium's largest BESS will be a practical test of that model. The bottom line: Green Turtle gives Belgium a four-hour battery large enough to matter at transmission scale. If it reaches service in 2028 on schedule, the project will show how brownfield land, bank debt, high-voltage access, and standardized LFP systems can turn European storage plans into operating grid infrastructure. Sources GIGA Storage project materials and construction-start announcement, ESS News coverage dated September 25, 2026, Power Technology financing coverage, VRT NWS local reporting, and GIGA Storage financial-close materials.