Mine sites hundreds of kilometres from any connection to the grid are catching on to renewables. It might take a lot of effort to install a clean energy system way out in the middle of nowhere but owners have decided it’s worth it when they look at the cost savings, the effects of taking some risk out of energy supply and emissions which can be offset.
Two systems delivered for Australian miners by engineering, procurement and construction company Juwi show how swiftly the sector has developed.
In 2016 Juwi completed a 10.6MW solar system to augment 19MW of diesel generation at the DeGrussa mine, owned by Sandfire Resources and located about 900km from Perth. Just four years later, the EPC connected a sophisticated power plant at Gold Field’s Agnew mine, 650km from Perth, that included 4MW solar, 4MWh of battery storage, 18MW of wind and back-up gas generators.
A comparison of the two projects highlights the how much has changed in the world of behind-the-meter microgrids that rely on solar PV and how single-axis tracking has gone mainstream.
When Juwi (pronounced You-we) worked on the DeGrussa system in 2016 there was only one other grid-scale PV plant that included tracking, says Juwi Renewable Energy head of development Andrew Drager. Since then, tracking has become the default option for utility-scale PV. “There is only a handful that are non-tracking,” he says.
Technology that turns solar panels to face the sun from dawn to dusk is something developers, financiers and mining companies can easily understand. And it works, with extra generation in the pre- and post-midday shoulders accounting for an increase in yield of about 25%, he says, leading to a 15-20% reduction in levelized cost of energy. “We also notice a lower O&M cost per kilowatt-hour,” Drager says.
Monofacial modules are installed at DeGrussa and Agnew (pictured above), with some bifacial panels included at Agnew for comparison’s sake. Juwi’s future projects that use tracking are “primarily bifacial”, he says.
Without sharing findings from the bifacial trial at Agnew Drager says the two-faced panels are delivering enough extra yield to outweigh the extra cost. “It does depend on the month and a number of other factors,” he says.
Nextracker director of sales Australia, South-East Asia and Pacific Andrew Chino estimates 80% of projects – utility-scale and off-grid behind-the-meter – are using or will use tracking. The company has completed about 75 projects in Australia since 2015, he says, or nearly 5GW deployed or contracted.
The system at DeGrussa has stood up well, despite a mini tornado which damaged dampers – support structures that stop panels oscillating in high winds – on some of the trackers. All dampers on the system were subsequently replaced by Nextracker with stronger versions. When winds pick up at DeGrussa the arrays will stow at 30° into the wind, Chino says.
The $112 million project attracted $13.5 million in funding from the Australian Renewable Energy Agency because the expected life of the mine only allowed for a short-term power purchase agreement, but that’s not to say owner Sandfire won’t switch from mining copper at the site to processing gold, commonly collocated with copper deposits. “There is a high likelihood the PV plant will stay there a very long time and keep supporting the mine as they extend the mine life,” Drager says.
Skills for the job
Over the past few years the restraining factor in the rollout of utility-scale PV has been the grid, Chino says. As investment slowly flows into transmission upgrades and development of renewable energy zones in NSW, Queensland and Victoria development of the grid will pick up. “While I don’t think the effects will be immediate, a few years down the road there will be a lot more opportunity,” he says.
It might mean we see a squeeze on skilled workers, but Drager cites DeGrussa as an example where installers who have gained familiarity with tracking systems would take about half the time to finish the same job today. Still, off-grid projects are elementally more complex, Drager says. They need to be integrated with existing power stations, for a start.
Nevertheless, there is demand for off-grid hybrid projects as companies – miners in particular – follow the scent of shareholder sentiment towards clean energy solutions and emissions reductions. Juwi has three hybrid projects on the go this year, he says. “For us, that’s a record.”
In a country that’s dotted with miners, it must be hard to know where to start. Drager admits it’s been an interesting experience.
“When I started a hybrid development company about eight years ago [that Juwi subsequently bought] I had a book with every mining company in Australia. I started at the beginning and called a good few hundred companies before I found the one that agreed to take a chance,” he says.
“Now it’s the opposite. Every third rooftop in Australia has solar PV, everyone understands that it works and now it’s just a case of cost. We’ve seen a lot more interest in the past 12 months driven by cost and shareholder expectations.
“The phone’s been ringing hot.”