Global clean energy enterprise TagEnergy has signed a 15-year, 105MW, four-hour virtual toll agreement with Snowy Hydro for its 150MW/600MWh battery energy storage system (BESS) at Golden Plains Wind Farm in Victoria, Australia.

The long-term deal is the first virtual storage contract for the newly announced Golden Plains BESS that will add flexibility and reliability to Victoria’s power supply to speed the energy transition.

The agreement comes as TagEnergy prepares to start building the BESS on site at the Southern Hemiphere’s largest onshore wind farm in early 2026, with the standalone storage facility expected to begin operating in late 2027.

TagEnergy’s Golden Plains BESS will work closely with Snowy’s current hydro assets and long-duration pumped hydro storage, including the Snowy Scheme and the Snowy 2.0 expansion, to dispatch energy into the grid at peak times and remove excess when demand is low.

TagEnergy Managing Partner Andrew Riggs said the virtual tolling agreement reinforces the vital role grid-scale batteries will play as a long-term energy solution underpinning the transition.

“The addition of large-scale energy storage at Golden Plains is another important step forward in achieving a more secure and flexible supply of clean electricity for the people of Victoria. It’s great to continue working with Snowy who have been an important partner for Golden Plains Wind Farm,” Mr Riggs said.

“This virtual toll arrangement will enable Snowy to leverage the flexibility of our storage assets without needing to build, own or operate their own. It will provide TagEnergy with a predictable revenue stream to balance market exposure from trading remaining capacity as merchant. And it will support integration of more renewable energy into the grid to balance the intermittency of wind-generated power for a more resilient, reliable and stable power supply,” he said.

The virtual deal secures new battery storage capacity for Snowy, providing it with access to large-scale storage products in the National Electricity Market (NEM) without the construction and capital burden of developing, owning and operating a physical facility.

Snowy Hydro CEO Dennis Barnes said the contract underscored the importance of on-demand and flexible capacity to ensure the National Electricity Market (NEM) remains reliable as base load power options like coal retire.

“We’re pleased to expand our partnership with TagEnergy, having previously secured 40 per cent of the supply from Stage One of their nearby Golden Plains Wind Farm. This new virtual storage agreement complements our portfolio of on-demand generation and gives us the fast-start power we need to quickly soak up excess wind and solar, and stabilise the grid at times of volatility,” Mr Barnes said.

The virtual tolling agreement extends the relationship between TagEnergy and Snowy Hydro into storage, after the pair signed the first Power Purchase Agreement (PPA) for Golden Plains Wind Farm in 2023.

The PPA saw Snowy Hydro take 40 per cent of the renewable energy generated by the now fully operational 756MW first stage of the 1333MW mega project. When the 577MW Stage Two is completed in mid-2027, Golden Plains will be the largest wind farm in the Southern Hemisphere and supply nine per cent of Victoria’s energy needs.