Wärtsilä to deliver record DC-coupled hybrid battery in Australia NEM

• Wärtsilä will supply a large DC-coupled solar-plus-storage system in Australia’s NEM, described as the market’s biggest of its kind, capable of serving 120,000 customers.

Wärtsilä has been tapped to deliver what it calls the largest DC-coupled hybrid battery system in Australia’s National Electricity Market, a project sized to power up to 120,000 homes and businesses. By wiring the battery on the DC side of the solar plant, the design reduces conversion losses, trims equipment count, and enables tighter control of energy flows between array and storage.

DC coupling differs from the more common AC-coupled approach by letting PV and batteries share inverters and step-up equipment. The advantages multiply at scale: improved round-trip efficiency, fewer grid interconnection constraints, and a simplified control stack that can respond faster to dispatch signals. For Australian conditions—intense sun, high temperatures, and increasingly steep evening ramps—the architecture promises better capture rates and more reliable peak support.

Technically, expect containerized lithium-ion blocks with sectionalized fire safety and robust thermal management, paired with grid-forming inverters that provide synthetic inertia, frequency-watt response, and ride-through in line with evolving NEM requirements. A supervisory energy management system will co-optimize charging from PV, discharge to the grid, and state-of-charge reservations for high-value evening periods, while also delivering fast frequency response and voltage support.

Siting at a strong node will be key to maximizing locational value and minimizing curtailment. The project’s DC layout should also simplify compliance with minimum-inertia and system-strength considerations by concentrating control in a unified plant controller rather than coordinating multiple AC assets.

Community and environmental measures are standard: construction traffic and noise management, landscaping to soften views, drainage sized for extreme rain, and coordinated emergency response plans with local fire services. End-of-life provisions will address responsible recycling pathways for batteries and solar hardware.

For the NEM, the project is a blueprint for squeezing more value from every installed megawatt of solar—soaking up midday surpluses, shifting energy into the dusk peak, and stabilizing the system in seconds. For Wärtsilä, it’s a flagship that showcases DC-coupled economics and grid-forming controls at utility scale.