50% renewable energy now 'commercially superior to diesel

MELODIE MICHEL, Reporter, Energy and Mines

There may still be a long way to go to achieve commercially viable 100% renewable energy projects for mines. But according to Dave Manning, Global Head of Hybrid at juwi Renewable Energies, recent projects have demonstrated that 50% renewable penetration is now easier than ever to reach, and makes better commercial sense than using 100% conventional power.

juwi was one of the partners in Gold Fields’ landmark Agnew hybrid power plant, having delivered the 4 MW single axis tracking PV installation, as well as a cloud forecasting and a microgrid control system, which were completed in the project’s first stage, in August 2019. At the beginning of this year, project developer EDL completed its second stage, adding 18 MW of wind capacity and a 4 MWh battery storage system to the plant. On average, the Agnew gold mine now runs on 50 to 60% renewable energy.

“The solar facility has been operating since September of last year and has met or exceeded generation forecasts. The full system, including wind and battery, has been operational as scheduled since Q1 2020 and the initial data shows performance as planned,” says Manning. To him, the Western Australian hybrid proves how far renewable energy and control technologies have come in terms of efficiency and economics. “Agnew demonstrates that 50% renewable energy with day and night-time power is now commercially superior to diesel, gas or grid-only solutions,” he adds.

The addition of wind allowed Agnew to push renewable energy generation into the night, dramatically increasing the amount of clean energy that could be used to power the mine. According to Manning, Gold Fields’ experience is likely to serve as a blueprint for future projects: “We see many mines where a combination of wind, solar and battery will deliver the lowest cash operating cost and the highest carbon emissions reductions. We are supporting several mines now by assessing their wind and solar conditions and designing a seamlessly integrated hybrid solution.”

In fact, juwi recently signed a contract with Pacific Energy for its next wind, PV and battery hybrid project. The project is being built for Horizon Power in Esperance, Western Australia, and while it is not a mine site, Manning says it shares many of the characteristics of remote Australian mines.

When it comes to the optimal percentage of a mine’s operational energy needs that can be delivered by renewable energy, Manning warns that there is no one-size-fits-all solution. “The right number is really site-specific, and while you can deliver well above 90% of renewable energy today, this will not deliver the best cash operating costs and be unbalanced towards high CAPEX,” he says. Still, juwi’s analysis shows that the best commercial outcomes for Australian mines with life of mines of 10 years or more is somewhere between 50% and 80% renewable energy. “The optimum renewable energy share has been increasing every year,” he adds.

Naturally, the mining industry’s focus on uncompromising power reliability has led to slower take-up of renewables than in other sectors, such as energy. Still, Environmental, Social and Governance (ESG) considerations are becoming key in discussions with miners, and Manning has observed a tangible increase in studies, solutions expressions of interest or full-blown project tenders in the past year. “COVID-19 has slowed down construction schedules and keeps pushing out final investment decisions on many projects. This means that short term project starts and completions are delayed, while mid-term project volumes are increasing,” he points out.

Additionally, he believes the trend is set pick up pace now that more and more real-life projects are coming to fruition. “We have been investing a lot of time to provide real-life data and case studies to mining professionals to distinguish between noise and proven solutions. With these insights, mining executives are able to make their operation more reliable and emissions profitable,” he notes.

But at the end of the day, the biggest argu- ment in favour of renewable energy is that it is now, in many cases, more economical than diesel or gas. “ESG is relevant for renewable energy, but I feel that the main driver now is lower cost and technical maturity and reliability of wind, solar and batteries,” adds Manning.

In the past 12 months, juwi RE’s team has been busy with projects such as an off-grid mine in Western Australia with around 10 to 12 MW off-grid power need, where they plan to integrate a wind, PV, battery hybrid with a gas fired power station. The team has also worked on large grid-connected mines, with the installation of utili- ty-scale PV systems to deliver the lowest cash operating cost. Other exciting opportunities shared by Manning include a mine in Africa with existing HFO genset fleet, which the team plans to hybridize with more than 30 MW of PV and battery capacity.

“I feel that Western Australia has led the way in hybrids for mines,” he says, “because of a combination or world-class expertise, supporting policy framework such as ARENA funding, and a strong and dynamic mining community. This has enabled WA to remain at the forefront of innovation and led some years ago to our decision to expand our operations from the eastern seaboard to WA.” juwi now has a team based in Perth delivering projects and working with key clients in WA. Still, Manning believes that the successes and experiences from Australia are transferrable and scalable and can be replicated in most locations globally, with Africa and Canada, in particular, following fast in Australia’s footsteps.

As renewable energy becomes a pillar in mine site energy systems, the growth of these technologies is accelerating the existing drive toward fleet and process electrification, enabling mines to operate without producing carbon emissions. This is leading juwi to focus particularly on integration. “This is why we have developed juwi Hybrid IQ. This mine-focused microgrid control system adapts to changing ore bodies and lowers cash operating costs with the best combination of wind, solar and storage in combination with fossil power stations. juwi Hybrid IQ is also ready to power electric fleet vehicles and provides data for process optimisations,” explains Manning.

The team has already conducted studies for mines that aim to achieve up to 100% renewable energy for their power needs, and identified commercial barriers at above 90% renewable energy. Still, Manning seems to believe these barriers can be taken down with the right amount of industry collaboration. He says: “Our ambition is to overcome even these barriers by working with mining experts to engineer solutions in mine design and process optimization with a mix of wind, solar and different storage technologies.”