Back in 2018, Gold Fields Executive Vice President Australasia Stuart Mathews asked the rest of the company’s board to take a leap of faith.

The long-standing power agreement for the company’s Agnew gold mine, located 375 kilometres north of Kalgoorlie, was coming to an end. There was an option to renew but given the aging nature of the power infrastructure and the likelihood more power would be needed, it was probable that an injection of capital would have been required.

There was, however, another option. What if an investment was instead made in renewable power, with wind and solar providing the energy for most of Agnew’s needs, while still having the reliability of gas to fall back on?

That concept was what Mathews requested that his fellow board members consider.

“I asked executive and the board to take some courage without the reserve life [of the mine] necessarily being there but with good vision on exploration success,” Mathews recalled.

“They went for it and said ‘let’s do it’. And we’ve been rewarded for it. I think part of the escalation in our share price is probably down to that because some of our biggest investors want to see companies taking action around emissions and climate change.”

The vast Agnew solar farm. ©: Csfoto – Christian Sprogoe photographer

Three years on and the hybrid renewable microgrid that was constructed by partner and energy solution specialists EDL at Agnew is a smash hit. It’s the largest of its kind in the country and also marks the first time wind generation has been used on a large scale at an Australian mine site.

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In October, the microgrid beat out a hot field that included Collie’s Lake Kepwari rehabilitation project to win the Golden Gecko award for environmental excellence category at the Department of Mines, Industry Regulation and Safety’s Resources Sector Awards.

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It has also won a string of engineering awards, including Engineering Solution of the Year at the 2020 Global Energy Awards.

But just as importantly, the microgrid has helped foster a sense of pride among the 650 or so staff who work at Agnew.

“People, especially younger people, want to work for a company that believes in sustainability – not just talking about it but putting actions in place,” Mathews said.

“What I really underestimated was what [the renewables project] did for the morale and motivation of our workforce at Agnew.

“It was phenomenal. We also built them a brand new camp, a really modern one moving them out of Leinster and back closer to the mine, and with the energy solution it’s the highest morale and motivation we have of any mine in our business.

“They are absolutely proud of it and people want to work there, including people putting their hands up to transfer from other sites to go to Agnew.”

By the numbers, the Agnew microgrid consists of five 110m wind turbines delivering 18MW of power, a 10.170-panel solar farm generating 4MW, a 13MW/4MWh battery system and an off-grid 21MW gas/diesel engine power plant.

When it went “live” in 2020, it was estimated to result in approximately 40,000 tonnes per annum of avoided carbon dioxide equivalents, which would correlate to taking 12,700 cars off the road each year.

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It was also forecast to provide more than 50 per cent of Agnew’s power needs but, as Mathews explains, it’s been even better than advertised in that regard.

“We have been as high as 70 to 80 per cent with optimal conditions – the winds just right and the solar working really efficiently,” Mathews said.

“For a very short period of time, maybe an hour or so, we well and truly did touch 95 per cent and almost got to 100 per cent.

“And we do have plans for the future which will deliver 90-plus per cent via renewables consistently.”

“What I really underestimated was what it did for morale and motivation of our workforce.”

stuart matthews

Gold Fields will pay off the cost of constructing the microgrid over a period of 10 years, after which energy expenditure – which makes up 25 per cent of the business’ costs – will, in Mathews’ words, “fall off a cliff.”

The success of Agnew has paved the way for Gold Fields to look at other assets and assess how renewables could fit with their futures.

A solar farm was installed at the company’s Granny Smith operation in the Eastern Goldfields late last year and wind options are being investigated to meet likely rising power demand as that mine goes deeper.

Solar is also being installed at the world-class Gruyere joint venture with Gold Road, while Gold Fields’ highly productive St Ives Mine south of Kalgoorlie-Boulder – its biggest in Australia and operational since the mid-1980s – is also the subject of a feasibility study around the potential addition of renewable energy.

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And it isn’t only Gold Fields taking note of Agnew’s success.

“I think we’re already seeing other companies learning from what we’ve done and going down that path,” Mathews said.

“And good on them. At the end of the day, it’s great to see people in the resources sector being prepared to take a leap of faith.

“I suppose a lot of others were holding back thinking ‘is it really going to work?’ and I must admit when we first started talking about wind I was someone who initially said ‘really?’

“But in the end I was convinced and I’m glad I was convinced. It’s something we really can be proud of.”

All photos copyright of Christian Sprogoe