The benefits of hybrid power technology for mining companies have increased significantly in the past few years and can now be compared against operational projects like the Sandfire-Degrussa Copper-Gold mine.
Dithering on making crucial decisions on energy sources can have a costly impact on a project in the medium to long-term. According to what African Mining Brief has gathered in an interview with Arnim Schön, Sales Manager Sub Saharan Africa at juwi Renewable Technologies (Pty) Ltd, investing in renewables today can provide substantial operational benefits, power price security and maximise shareholder value. Schön supports mines on how to best handle the following areas: Feasibility and Planning Stage, Rental vs Power Sale or Plant Ownership, Implementation, and Post-commissioning Support.
There are a number of aspects that determine the most reliable and lowest cost power solution. , For hybrids the following aspects are are vital: Life of Mine, Power costs, Mine location (grid connected or grid) and Hybrid System Integration, as captured below, advises Schön.
- Life of mine
Renewable energy technology has matured and reduced in cost to a level that it can provide Cash Operating Cost reductions for many mines with Life of Mine of 5 years or more. The longer the life of mine, the more attractive will be a hybrid solution.
- Power costs
The current or planned cost of power without hybrid serves as the benchmark to determine if solar, wind or batteries could deliver power at the same or at lower costs. Schön adds: As a rule of thumb renewables will improve Cash Operating Costs for most mines that have 5 or more years of mine life ahead of them.
- Mine location: Grid connected or off grid
If a mine is connected to the grid, solar or wind power plants behind the meter produce power cheaper than the grid in most cases. Even if there is not enough land available or the local wind or solar conditions are not favourable, power could also be wheeled contractually from a different location. In both cases, notes Schön, the hybrid solution will mitigate risks from unstable grids or future price increases. “Combining solar with battery storage will also aid in power smoothing to further absorb the impact of an unstable grid as well as balancing power output during cloud events for example.”
If a mine is off-grid and runs on Diesel, LFO or HFO generators, a hybrid solution will likely save even greater amounts in Africa, he advises. “A hybrid power plant incorporating solar, storage or even wind will significantly reduce the fuel costs and carbon emissions. If you consider that up to 85% of the cost of electricity of a thermal plant comes from fuel costs the magnitude of savings become visible. On top of that, a hybrid solution will provide additional savings on O&M of the thermal power plant,” he remarks.
- Hybrid system integration
Integrating solar, battery or even wind into thermal power stations at mine sites is not as simple as designing and building a solar rooftop for a home or a standard grid connected plant. A powerful, robust and reliable hybrid micro-grid controller and SCADA system are as essential for project success as the integration expertise and experience in mining environments.
On how juwi handles this challenge, Schön explains, “Despite being a technology agnostic EPC and project developer juwi could not find a suitable SCADA solution that could properly cover all generation assets. That is why we have developed and successfully deployed our own juwi hybrid SCADA. juwi’s hybrid SCADA has been running now successfully since 2016 at the Degrussa Copper/Gold mine in Australia.”
- Location and resource area
Last but certainly not least, Schön mentions the wind and solar resource and the availability of land as central to the planning of a hybrid power generation plant
“The first question to be asked is: Does the mine have the space and suitable land for constructing a solar plant or the ability to wheel power from elsewhere? As a rule of thumb for Africa, a solar power plant requires 1 to 2 ha per Megawatt capacity.
“The second question is: Is the mine in a good solar or wind resource area. With regard to Africa, juwi has established that, providentially, almost all African locations have enough sunshine and some locations have excellent wind conditions,” Schon states.
Rental or ownership?
Outsourcing is all the rage in contemporary mining conditions. This has led to the fallacious notion that rental rather, power sale agreements or ownership is the most aviable option for mining companies. But Schön begs to differ, at least based on juwi’s experience.
On the contrary, argues Schön, the reality is that the decision on whether to rent, enter into an energy sale agreement or purchase a power plant, depends on the duration of a contract. “One can say that renting of gensets has its place in a mining environment but is normally seen as a gap filler for something more permanent and cheaper in the future. For contracts with only 1 to 3 years, rental might be financially sound. Anything longer appears to favour either entering into energy sale or power purchase agreements with a power provider or alternatively an outright purchase and operation of a power plant by the mine themselves. Hybrids could be rented too but, to date, the market has not reached the scale yet that enables widespread rental solutions.”
Vital steps in implementation
From juwi’s perspective, solar and wind resources assessment, system design, hybrid integration and mine site execution track record are key factors for success during. The company evaluates options with the aim of delivering the highest reliability at the lowest possible power cost..
“juwi has developed and uses sophisticated software tools to simulate scenarios and determine optimal configurations and designs. Our clients additionally benefit from more than 22 years of operational experience globally. Projects on all continents with more than 4,400 MW capacity provide us a wealth of data to compare our assumptions against, including many African projects and the hybrid power plant at the DeGrussa mine in Australia,” Schon describes the juwi’s competencies.
Even though solar is a low maintenance technology the hybrid plant should be professionally monitoring during regular operation to ensure optimal performance. To handle this demand, juwi offers a wide range of operations and maintenance options for hybrid plants.
Beyond cost savings
Schon closes by stressing numerous benefits that hybrid power plant bring to a mining area and beyond. “We have seen that renewables offer so much more than pure cost savings to mines. Power price certainty, millions of litres in fuel and carbon savings, and last but not least, a strong statement that an organisation actively implements sustainable solutions and cares about the community and the environment it operates in. We have seen for example that mining employees and communities positively associate with their solar power plant. The social license to operate becomes ever more important to successful mining companies and renewables stand out like no other technology that respect.”
juwi’s experts are keen to help mining managers in Africa address their respective demands in hybrid solutions in Africa as ramp up production.