IN Brief:
- Green Turtle combines 700MW of power with 2,800MWh of storage using 640 Tesla Megapack 3 units.
- The project will connect directly to Belgium’s high-voltage system beside Elia’s 380kV Van Eyck-Gramme line.
- Tesla leads EPC delivery while STADSBADER is undertaking substantial civil works ahead of commissioning in March 2028.
GIGA Storage has started construction of its Green Turtle battery energy storage project at Dilsen-Stokkem in Belgium, moving the 700MW/2,800MWh scheme from financing and development into physical delivery.
The project will use 640 Tesla Megapack 3 battery units and is planned as a four-hour system, with 700MW of power and 2.8GWh of energy capacity. GIGA Storage expects the installation to enter service at the end of March 2028, following preparatory earthworks and roadworks that began in mid-August.
Green Turtle is being developed on the former Société Anonyme de Rothem zinc-factory site at the Rotem industrial estate. The location places the storage plant immediately beside high-voltage infrastructure operated by Belgian transmission system operator Elia.
Elia is building a new high-voltage substation at Rotem, and Green Turtle will connect directly to the Belgian transmission network close to the 380kV Van Eyck-Gramme line. The project specification includes 188 medium-voltage transformers and four high-voltage transformers, showing the scale of the balance-of-plant equipment required around the battery enclosures themselves.
Tesla is the engineering, procurement and construction partner and will supply the Megapack 3 systems, undertake engineering and construction, commission the installation and provide long-term maintenance. STADSBADER CONTRACTORS is carrying out the civil works for Tesla and is also involved in neighbouring high-voltage infrastructure for Elia.
The civil package includes approximately 45,000m³ of earthworks, around 7,350m³ of concrete and 933 tonnes of reinforcement steel. Transmission-connected storage requires foundations, internal roads, drainage, cable routes, fire separation, transformer compounds, control systems and a grid interface capable of handling hundreds of megawatts before the battery blocks themselves can operate as a single plant.
The construction programme follows financial close for Green Turtle in July. That earlier milestone assembled the capital required for delivery; the current phase shifts the programme towards civil progress, equipment manufacture, high-voltage works and the sequence needed to energise the plant safely.
At full output, the nominal ratings give Green Turtle a four-hour discharge duration. That extends the usable energy reservoir well beyond the short-duration batteries built primarily around early frequency-response markets, while still allowing fast response where the plant’s control systems and state of charge permit it.
The developer intends to make capacity available to Elia and market participants for balancing and congestion-management services. Actual dispatch will depend on state of charge, market prices, network requirements, equipment availability and contractual limits. Control systems will therefore have to coordinate physical constraints against changing system and market conditions throughout the day.
Green Turtle will use lithium iron phosphate batteries, avoiding cobalt in the cell chemistry. LFP has become widely used in stationary storage because thermal stability, cycle life and cost can carry more weight than the very high energy density sought in some mobile applications. A fixed installation is also less constrained by the additional footprint than a road vehicle.
Commissioning a 700MW battery will proceed through staged testing rather than a single energisation event. Individual battery blocks, power-conversion equipment, transformers, protection systems, communications, metering and high-voltage interfaces will have to be tested in sequence before the aggregated plant response is accepted.
Grid-code compliance will include the system’s behaviour during voltage and frequency changes, faults, control commands and the loss of individual equipment. Protection coordination, harmonic performance, reactive-power capability and communications with the system operator are central to acceptance because the plant must behave predictably during disturbances as well as during routine charging and discharging.
The site also includes a 26,650m² area of native planting around the installation. The electrical function remains the primary purpose, but the project is being delivered as permanent energy infrastructure with planning, ecological, construction and community obligations alongside the high-voltage scope.
The electrical connection also sets the project’s delivery sequence. Medium-voltage collection equipment has to aggregate the battery blocks before power reaches the main high-voltage transformers and Elia interface, while protection zones and control systems must be commissioned progressively. Cable installation, transformer energisation and substation readiness therefore constrain when individual sections can move from mechanical completion into electrical testing.
That sequencing reduces the value of treating battery delivery as the sole critical path. A completed Megapack cannot contribute to the system until auxiliary supplies, communications, protection and the transmission connection are available, and delays in civil or high-voltage packages can hold back otherwise finished battery equipment.
Construction now puts equipment delivery, civil works, substation progress and commissioning on the same timetable. Green Turtle is scheduled to enter service at the end of March 2028, leaving the project team to align 640 battery units, associated transformers and a direct 380kV connection through the remaining build and test programme.
