Gamuda Australia and renewable energy developer Yanara have signed the delivery contract for Stage 1 of the Mortlake Energy Hub in western Victoria, moving a 435MW solar and large-scale battery project into its main construction phase.
Mortlake Energy Hub Stage 1 will combine 435MW of solar generation with a 300MW battery energy storage system designed for 4.5 hours of discharge. The project will connect to Victoria’s existing 500kV network through the Mortlake Terminal Station, allowing electricity generated during periods of strong solar output to be stored and dispatched later.
Gamuda was originally appointed in October 2025 under an early contractor involvement arrangement. That phase allowed the contractor and Yanara to progress design, procurement, environmental planning, construction methodology, and engagement before execution of the full engineering, procurement and construction contract.
The companies say design and procurement have reached around 80%, compared with approximately 30% under what Gamuda describes as a more traditional early contractor involvement stage. Completing more engineering and purchasing before site activity reaches its peak is intended to reduce uncertainty around equipment availability, design interfaces, and construction sequencing.
Early works are expected to begin before main construction starts in November 2026. Initial activity includes upgrades around the Hamilton Highway intersection close to the site entrance, preparing the transport route for the larger flow of equipment and construction traffic that will follow.
Gamuda expects the project to be energised in April 2028, with commercial operations planned for the first quarter of 2029. More than 300 jobs are expected to be created during delivery.
The engineering challenge comes from integrating generation, storage, and a high-voltage connection as one operating asset. Solar output varies with irradiance, while the battery can charge or discharge according to network conditions, market requirements, and its available state of charge.
Controls therefore have to coordinate photovoltaic inverters, battery power conversion systems, transformers, protection equipment, communications, and the transmission connection. The equipment has to respond quickly enough to system instructions while remaining within thermal, electrical, and battery operating limits.
The 500kV connection places Mortlake directly on Victoria’s high-voltage transmission network. That requires substantial electrical infrastructure beyond solar modules and battery containers, including switchgear, transformers, protection and control systems, communications, civil structures, and equipment able to withstand transmission-level fault conditions.
Battery duration changes what the project can contribute. A 300MW system designed for 4.5 hours can shift a larger block of energy than shorter-duration batteries focused primarily on rapid balancing services. At nominal rating, the published power and duration imply around 1,350MWh of usable storage before allowing for the detailed operating limits of the final system.
Separate project disclosures have referred to a different megawatt-hour figure, so the current Industrial News package uses Gamuda’s primary engineering specification of 300MW and 4.5 hours rather than attempting to reconcile unpublished design assumptions.
The hybrid arrangement allows part of the solar plant’s daytime output to be stored rather than exported immediately. That becomes more useful as renewable penetration increases and periods of strong solar generation coincide with lower wholesale demand or network constraints.
Storage can then release electricity later in the day, respond to grid requirements, or retain energy that might otherwise be curtailed. The commercial value depends on market prices, network conditions, operating strategy, battery degradation, and the efficiency of each charge and discharge cycle.
Mortlake also illustrates the changing role of electrical equipment in renewable projects. Transformers, switchgear, power electronics, and grid connection assets increasingly sit on the critical path because manufacturers are serving simultaneous demand from renewable generation, storage, transmission expansion, data centres, and industrial electrification.
Gamuda’s decision to advance procurement during the early contractor phase is intended to manage some of that exposure. Long-lead equipment can be ordered earlier, while design teams have more time to resolve the interfaces between civil works, electrical systems, the battery installation, and the transmission connection.
Stage 1 forms part of a larger proposed Mortlake Energy Hub, with later development intended to add further storage capacity. The first stage contains most of the planned solar generation while establishing the network and control infrastructure around which later expansion could be integrated.
The project sits within Victoria’s target of reaching 65% renewable electricity by 2030 and 95% by 2035. Targets do not determine the performance of an individual asset, but they increase the requirement for transmission capacity and flexible resources able to manage a system with a larger share of variable generation.
Signing the delivery contract moves Mortlake from development into a defined construction programme. With much of the design and procurement already advanced, the next test is physical execution: civil works, equipment delivery, electrical installation, battery integration, and eventual energisation all have to remain aligned for the April 2028 connection target to hold.
