Australia’s largest off-grid hybrid power system goes online at remote mine after overcoming floods

A mammoth gold mine in Western Australia is now home to the country’s largest off-grid hybrid power system following the installation of 61MW of renewable energy to an existing gas-fired power station.

Pacific Energy, a Perth based provider of sustainable distributed energy that has operated for over four decades, announced on Monday that the 61 MW of new wind, solar and battery storage were now operating at the Tropicana gold mine, located 330 kilometres northeast of Kalgoorlie.

The newly expanded hybrid power system now includes four 6 MW wind turbines, a 24 MW solar farm, and a 13MW grid-forming battery energy storage system (the storage duration has not been revealed but is likely to be no more than one hour).

The addition of renewable energy components complements a 54MW gas-fired system, bringing the hybrid power station’s capacity up to 115MW – the largest off-grid hybrid power system to power a mine in Australia.

The mine will be capable of operating on 100 per cent renewables thanks to what Pacific Energy describes as an “ultra-responsive hydrocarbons-off functionality”.

Nevertheless, Pacific Energy predicts that the expanded renewable energy capacity will reduce Tropicana’s diesel and gas consumption for power generation by 96 per cent and 50 per cent respectively, resulting in cuts to carbon emissions of an average of 65,000 tonnes each year over the life of the agreement.

And, according to Pacific Energy’s chief executive, Jamie Cullen, the system is already outperforming targets.

“The new assets have already generated over 38,000 megawatt hours of renewable energy, and that’s mostly while we were still bringing the equipment online,” said Cullen.

“We’re also on track to displace an average of more than 1,100 terajoules of gas with solar and wind generated power every year, and we expect to almost entirely displace diesel, which is now there purely for emergencies.

“In real-world terms, these fuel reductions will reduce Tropicana’s power generation emissions by upwards of 45%, which is equivalent to taking more than 14,000 cars off the road.”

Construction of the renewable energy expansion began in mid-2023, with the first wind turbine footings completed in August of last year as wind turbine parts began arriving. It was delivered under a 10-year build-own-operate agreement with mine owners AngloGold Ashanti Australia Ltd (70% and manager) and Regis Resources Ltd (30%),

A few months later, Pacific Energy announced that the recently completed solar farm had successfully supplied the entire mine load for 40 minutes – an important milestone in bringing the project to completion.

Completing the project required tackling a number of challenges, including severe flooding during the construction phase.

“Our Tropicana project involved more than 200,000 onsite labour hours, so it’s only through careful planning and our team’s collective commitment to safety best-practices that we’ve delivered this in a live mining operation with zero lost time injuries and zero medically treated injuries,” said Cullen.

AngloGold Ashanti has targeted a reduction to its global net carbon emissions from energy use of 30 per cent by 2030, on the road to achieving net zero carbon emissions by 2050.

The hybrid power system is the first of its kind to be implemented across the AngloGold Ashanti group’s operations.