DECARBONIZING THE MINING SECTOR

ENERGY AND MINES: How is the overall drive to decarbonize shifting the thinking and approach to mining hybrids?

STEPHANIE MOROZ: Globally, there is momentum to decarbonize all industries, including the mining sector. Many mining companies have committed to net zero carbon emissions by 2050, with specific carbon reduction targets much sooner. However, mines are often located in remote areas and rely on diesel or natural gas-fueled power stations—typically the site’s largest source of carbon emissions.

Miners are looking to reduce these emissions with hybrid power stations involving solar, wind and battery storage to provide high renewable energy (RE) penetration electricity—the first step in decarbonizing mining. In the last decade, wind, solar and battery costs have decreased while fossil fuel prices have increased, making hybrids viable. Only a few years ago, miners were reluctant to risk incorporating renewables, but now they expect at least 50% RE and are asking us how we can go even higher.

E+M: EDL has had lots of experience leading high-penetration renewable energy hybrids for mining companies in Australia, can you tell us about some of these showcase projects?

SM: The Agnew Hybrid Renewable Microgrid, now in operation for more than two years, provides the Gold Fields mine with 50-60% RE while maintaining power quality and reliability. It’s the largest of its kind in Australia with 18MW wind, 4MW solar and a 13MW battery—the first to utilize wind generation on a large scale at an Australian mine site.

As mining companies decarbonize their operations, multiple technologies are key to achieving this goal. Stephanie Moroz, Head of Technology and Innovation at EDL, talks about the current developments helping the mining sector work towards net zero.

At Jabiru in the Northern Territory, the hybrid power station (solar, battery and diesel backup) provides the township with at least 50% RE and 100% solar energy throughout the day— helping it transition from its mining legacy to a tourism and services hub. The significant milestone achieved with this project is reliably supplying the town demand from 100% renewables when available and turning the diesel generation off. But watch this space–we’re currently working on the next step change to even higher RE.

E+M: What are some of the key takeaways from these mining hybrid solutions to date?

SM: We have gained many important learnings from developing and operating technically complex hybrid renewable microgrids for off-grid mines in diverse locations. It’s a constant learning and development process. Based on our experience, the biggest lesson is that while hybrid solutions may appear simple on the surface, in reality, they are technically complex and challenging to design and deliver. Wind, solar, battery and thermal generation all have very different characteristics. Ensuring that the microgrid maintains power quality at all times requires advanced capabilities in managing these interfaces.

E+M: What opportunities do you see for high-penetration renewable energy hybrids for North American mines?

SM: We have found that hybrids deliver outstanding performance—matching or often exceeding main grid reliability. Like in Australia, there are many mines in North America located in isolated areas with harsh climates relying on diesel fuel for power. Many areas in Canada have excellent wind resources, and regions with a dry climate have long days of reliable solar irradiance during the summer months. EDL’s experience with complex logistics delivering equipment over long distances with weather-dependent access to site is highly relevant to the Canadian context.

E+M: What are the remaining challenges for miners as they look to increase the amount of renewable energy and storage as part of remote power systems?

SM: Depending on the solar and wind resources and the fuel price, there is an economic optimum of anywhere between 40% and 90% RE. Beyond that level, any additional renewable generation and storage experiences lower utilization—translating to a higher cost per unit of power delivered. The challenge in the design phase is finding the right combination of components to deliver the highest % RE most economically. This requires accurate data for the solar and wind resources, combined with a detailed understanding of the load profile and the electrical system.

It also involves familiarity with equipment from different suppliers to determine how best to bring them together and how to control them. Much of that is based on past experience. With each project, EDL incorporates the learnings from previous projects to achieve performance targets more costeffectively.

E+M: Which key technologies are best supporting the transition to less fossil fuels for off-grid mines?

SM: There isn’t one single answer. We will need to take multiple approaches in parallel to achieve our decarbonization goals. Once the optimum % RE is achieved in the power system with renewables and batteries, further decarbonization is more cost-effective through increasing electricity use, for example, electrifying vehicles and other fossil-fueled processes. The challenge for miners is to source reliable electric options that can replace diesel-powered vehicles and equipment. Fuels such as renewable natural gas (RNG) or renewable diesel can decarbonize the remaining processes that are difficult to electrify.

Our experience producing renewable natural gas (RNG) from waste at our North American landfill gas sites demonstrates that we can provide biogas or biofuels to power mobile equipment such as trucks and buses. Renewable hydrogen produced by electrolysing water with renewable electricity may provide another solution in the future—delivered as either hydrogen or processed into a renewable hydrocarbon fuel.

E+M: For mines with shorter lives, what are some of the options for building flexibility and affordability into a hybrid power solution?

SM: Hybrid power solutions involve a wide range of options, and the assumed project life is an important factor in the commercial outcome. For short mine lives, some equipment such as batteries can be designed for relocation and re-use at another mine. We are also assessing solar panel providers who can move their equipment. Mining companies look beyond the initial mine life when considering hybrid solutions. A long-term approach can deliver improved economic and environmental benefits for our customers.

Meet Stephanie Moroz at the Energy and Mines Toronto Summit, Nov 1-2. She is participating on the panel: Key Considerations for Renewable Energy Hybrids for Mines