Mines operate 24/7 and the integration of power supply between various power sources and a mine is a significant factor in the implementation of hybrid renewable energy solutions. juwi has focused on resolving the integration challenge with their SCADA system which seamlessly integrates the control systems from thermal, renewable and plant control, and gives the client good visibility of the functionality of every aspect from one central point. Amiram Roth-Deblon, Head of Global Business Initiatives, and David Manning, Global Head of Hybrid at juwi, discuss meeting the challenge.
Amiram: When we look at integrating hybrids at a mine site, we look at first and foremost the operation of the mine. What are the resources? What’s there? We’ve realised in our previous projects we understand renewables very well, we understand integrating renewables into grids very well but also our understanding on the mine side was somewhat limited. That’s why I’m very glad that we got a recognised leader in that sector with us now and I’d like him to explain a bit more.
Key considerations when integrating hybrid energy into a mine site
David: One of the key factors to integration is consideration of the mine site loads, such as the Ball and Sag mills, in underground mine sites, the Vent Fan configuration, and in some cases, the camp loads. We need to understand the entire processing plant operation, so that when we set up our permissive starts and stops and the interaction between the power station and process plant operation, we ensure we give priority to critical aspects of the mine site operation. For example, in a leach plant, the last thing we want to do is lose power to the agitators. It’s one of the things we keep in account when we look at our load shedding regime, to make sure that if we do have to shed load, we leave critical aspects like agitators to the last. We can take power off to the camp, we can shed non critical loads and keep the mills running. The entire mining process is critical and that’s what we have to bear in mind when establishing the load shedding regime and the set-up of the mine site.
Amiram: As you can see, the depth of understanding we need here is very different from a normal renewable energy project. It’s about the hybrid controls, integrating all the renewable and thermal power generators and understanding the mines, their energy needs and operations.
David: I think if we get a good understanding of the load, we can optimise the power so that we’re not carrying massive amounts of spinning reserves. We’re utilising the battery storage effectively and we’re not burning unnecessary diesel to maintain a continuous supply.
The SCADA system
David: What we call the hybrid controller is at the heart of the operation and building a controller that works seamlessly to bring all three aspects of the hybrid system together is paramount. We put substantial engineering into developing the system, ensuring that the process works seamlessly and there is zero interruption to supply. The system balances out renewable energy, thermal energy and continuous supply. Maintaining power factor, stability and supply is what it’s all about. It’s what juwi excels at.”
In a typical mine site, the mine site operator likes a lot of visibility as to what’s going on with their energy supply. In a lot of cases power supply makes up 30-40% of the cost of operations in a mining operation. It’s very much at the forefront of what mining operators want to see. juwi has developed a very good SCADA system and it gives our client visibility of what’s happening with their control systems so they can see the amount of PV penetration and the amount of wind penetration, they can see their fuel costs, they can see their reliability.
What we find is once we open up our system to our client and give them good visibility, it gives them comfort and security in knowing they have a reliable supply. It also allows them to track their costs and manage their cost base and see where they’re at.
SCADA seamlessly integrates the control systems from thermal, renewable and plant control. What we find is that the solar providers provide a good interface; the wind providers provide a good interface and the mine sites have their own interfaces as well. What juwi does is bring all that together into one SCADA system that controls everything and gives us seamless integration into all aspects of the operation.
Renewable integration at DeGrussa, Australia
Amiram: Effective integration ensures significant cost-savings, as we’ve proven for more than two years at the DeGrussa Sandfire Power Plant. We’re saving 450 000 litres of diesel each month, which exceeds our forecast of 5 million litres per year.
David: I think what was highlighted at DeGrussa is that the renewable integration occurred without interruption to the mine site’s operation. It was done at a power station that was running for many years with a control system that was never designed for renewables. juwi was able to come in and implement, design and commission a renewable energy solution without interruption to supply. I don’t think we lost one day of operations through the integration – it’s quite a success story.