Gold Fields says its 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 following a deal with global energy group EDL.

Gold Fields and EDL have agreed on a A$112 million ($78 million) investment in what the gold miner says is a “world-leading energy microgrid combining wind, solar, gas and battery storage”.

The Agnew mine consists of two underground complexes and one processing plant, with a capacity of 1.3 Mt/y consisting of a three-stage crushing circuit, two-stage milling circuit, gravity circuit and carbon-in-pulp circuit.

The microgrid will be owned and operated by EDL, which will recoup its investment via a 10-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, according to Gold Fields.

The Agnew microgrid is initially forecast to provide 55-60% of the mine’s energy needs, with potential to meet almost all energy requirements at certain times, Gold Fields said. The Agnew microgrid will consist of five wind turbines delivering 18 MW of power, a 10,000-panel solar farm contributing 4 MW, a 13 MW/4 MWh battery energy storage system, and a 16 MW gas engine power station to underpin supply when required.

EDL said stage one consists of a new off-grid 23 MW power station incorporating 16 MW gas and 3 MW diesel generation and 4 MW photovoltaic solar, which is on track for completion in mid-2019. Stage two includes 18 MW wind generation, a 13 MW battery and an advanced micro-grid control system, with construction recently started and due for completion in 2020.

The hybrid microgrid at Agnew follows the announcement of a microgrid at Gold Fields’ Granny Smith mine, featuring 20,000 solar panels and a 2 MW/1 MWh battery system planned for completion in the December quarter.

Gold Fields Australia Executive Vice President, Stuart Mathews, said 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.

“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,” Mathews said.

The funding is part of ARENA’s Advancing Renewables Programme. ARENA CEO, Darren Miller, said 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,” Miller said.

Gold Fields says it is embracing innovation and technology across all levels of its mining operations and Mathews said this also extended 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,” he said.

EDL CEO, James Harman, said 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 said. “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.”

Mathews said: “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.”

Gold Fields is the third largest gold producer in Australia. It currently owns and operates three mines in Western Australia and is completing the construction of a fourth, Gruyere, in joint venture with Gold Road Resources.