Sustainable gold miner Gold Fields’ Agnew gold mine, in Western Australia, will become one of Australia’s first mining operations to be predominantly powered by renewable and low-carbon energy.

In June, Gold Fields and global energy group EDL announced a A$112-million investment in the world-leading energy microgrid combining wind, solar, gas and battery storage. The microgrid will be owned and operated by EDL, which will recoup its investment through its ten-year electricity supply agreement with Agnew.

The project, which is already under construction, has the backing of the Australian government with the Australian Renewable Energy Agency (Arena) contributing a recoupable A$13.5-million to its construction.

The Agnew microgrid is initially forecast to provide 55% to 60% of the mine’s energy needs, with potential to meet almost all its energy requirements at certain times.

The Agnew microgrid will consist of five wind turbines which will deliver 18 MW of power, as well as a 10 000-panel solar farm contributing 4 MW. The energy supply will be supplemented with a 13 MW battery energy storage system (BESS) producing 4 MWh and a 16 MW gas engine power station to underpin supply when needed.

“The Agnew hybrid microgrid project reflects the company’s strategic objective to strengthen energy security, optimise energy costs and reduce its carbon footprint through innovation and the adoption of new technologies,” says Gold Fields Australia executive VP Stuart Mathews.

“The Arena contribution supports and encourages our efforts. We are making staged investments across our mines in Western Australia to significantly ramp up the innovative use of renewables to meet our dynamic and growing load requirements,” adds Mathews.

The funding is part of Arena’s Advancing Renewables Programme.

Arena CEO Darren Miller highlights that the project marks a growing shift in the mining sector’s thinking around powering mine sites. “The project Gold Fields is undertaking will provide a blueprint for other companies to deploy similar off-grid energy solutions and demonstrate a pathway for commercialisation, helping to decarbonise the mining and resources sector,” says Miller.

Gold Fields is embracing innovation and technology across all levels of its mining operations and Mathews suggests that this also extends to its approach to power supply and demand management.

“At Agnew, we will be using instrumentation to detect approaching cloud cover for solar and, potentially, in the future, detect changes in wind velocity. Based on this data, the gas power station will have forward-looking systems in place to schedule gas generators in response to forecast changes in the renewable-energy supply,” Mathews adds.

EDL CEO James Harman points out the company has seen increasing momentum towards hybrid energy solutions, particularly in remote, off-grid locations. “EDL is pleased to be an active contributor to Australia’s transition to sustainable energy,” Harman says. “Our knowledge and experience from our successful hybrid renewable projects will enable us to provide Agnew with greater than 50% renewable energy over the long term, without compromising power quality or reliability.”

The hybrid microgrid at Agnew follows the announcement of a microgrid at Gold Fields’ Granny Smith gold mine, near Laverton, in Western Australia. The microgrid will feature 20 000 solar panels and a 2 MW BESS producing 1 MWh planned for completion in the fourth quarter of this year.

“The configuration of Agnew’s hybrid solution is a first for Gold Fields, and is an excellent example of using innovation and technology to improve efficiencies and lower costs. “We are fast sharing lessons from this project with our other regions, as part of our global strategic initiatives to improve our security of supply and reduce carbon emissions,” Mathews concludes.