Alinta to build 200MWh big battery next to Alcoa aluminium plant to soak up solar

Alinta Energy has locked in plans to build a big battery alongside a peaking gas and diesel plant and aluminium refinery in the south west of Western Australia, to help stabilise the grid and provide backup power.

Alinta said on Thursday it has appointed Shanghai Electric Power Design Institute and Sunterra to build the 100MW, two-hour (200MWh) battery at the Wagerup Power Station at Alcoa’s refinery of the same name in south-west Western Australia.

The Wagerup battery is second privately owned battery project to win a contract from the Australian Energy Market Operator to help solve some of its supply challenges in WA’s South West Interconnected System, the world’s biggest micro-grid.

Like the 219MW/877MWh Collie battery to be built by Neoen, the Wagerup battery will be paid to soak up solar in the middle of the day, before discharging into the evening peak.

It is one of many batteries being sought by AEMO and the state government as it seeks to manage the impending closure of its remaining coal fired generators, and the massive growth in energy demand sparked by electrification and the push into green hydrogen and processing and refining.

See: World’s biggest micro-grid needs gigawatts of new battery capacity – and very, very soon

Construction on the Wagerup project, first flagged by Alinta in 2021, is expected to start straight away, with the commissioning of the big battery scheduled for the second half of 2024.

As RenewEconomy has reported, the Wagerup battery has superseded Alinta’s previous plans – for which it secured approval more than a decade ago – to build a 350MW “co-generation” plant to provide more “baseload” power at the site.

That’s because, for networks making the shift to renewables, the focus has turned to big batteries for their fast response and flexibility to fill in the gaps in wind and solar – a particularly important task for WA’s main network, the South West Interconnected System (SWIS), as the world’s biggest isolated grid.

The first big battery to be connected to WA’s grid was the 100MW/200MWh system commissioned by fellow state-owned utility, Synergy, to help reduce the strain on gas generators responding to the variations of wind and solar.

That project, the Kwinana big battery, was switched on in May of this year. Several other batteries have been built off-grid at the site of mines, and in the mini-grids that power the giant iron ore mines in the north of the state.

Alinta has its own plans for remote and regional renewables and batteries in WA, including a proposed 90MW solar farm and 60MW/120MWh big battery in Port Hedland.

Alinta also has long terms plans to build a wind farm of up to 600MW elsewhere in the Pilbara, but is waiting to see how the north west grid evolves.

Just last week some of the country’s biggest miners agreed to work together to create what could be one of the world’s biggest renewable energy hubs, rather than building a series of private networks.

For Alinta’s Wagerup battery, the utility appears to have gone for the same configuration as Kwinana, which was designed to provide instant frequency response to incidents on the grid and well as to provide power at peak times, or to smooth out the variations of wind and solar.

“This project is a great example of how Alinta Energy, Western Power, AEMO and our key supply partners are rapidly mobilising to ensure the electricity system in South West WA has the smoothest transition to renewables possible,” said Alinta chief development officer Ken Woolley in a statement on Thursday.

“The battery will connect to existing high voltage infrastructure at the Wagerup Power Station,” he added, “…stabilising the South West WA grid, and providing backup capacity when needed,” he said.

See also RenewEconomy’s Big Battery Storage Map of Australia