Engineering & Mining Journal

MAR 2019

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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Page 35 of 67

34 E&MJ • MARCH 2019 ENERGY EFFICIENCY • Grid-connected sourcing green energy – The mining company buys green pre- mium products or pays green tariffs to a utility. • Industrial Pooling – Several companies commit to buying electricity from an IPP, making a RE project viable. • Self-generation – The RE power pro- ject is built and owned by the mining company. For example, as part of a cost-reduc- tion program and drive to manage its carbon footprint, Barrick Gold's Loulo operation in Mali plans to install a 24- MW off-grid solar hybrid plant to sup- port its existing 63-MW thermal power station. The company said the solar plant has the potential of saving 10 mil- lion liters of fuel a year while reducing Loulo's annual carbon emissions by 42,000 metric tons (mt). Barrick said the RE project is part of its strategy of moving away from thermal power in Africa, where lack of infrastruc- ture means that many mines need to rely on self-generated diesel energy, making this their largest cost item. According to a solar feasibility study, the photovoltaic plant is expected to re- place 50,000 MWh/y of thermal genera- tion. The introduction of the solar com- ponent will cut the complex's energy cost by around 2 cents/kWh. Construction of the project, which Barrick said meets its investment criteria of 20% IRR, will start later this year, and it is scheduled for commissioning in late 2020. The plant will use the latest weather predic- tion models, which will enable the power management system to switch between thermal and solar without compromising the microgrid. Meanwhile, Gold Fields' Granny Smith gold mine is planning to install a micro- grid powered by more than 20,000 solar panels and backed up by a 2-MW /1-MWh battery system. The mining company contracted mo- bile and modular power company Aggreko to design, build and operate the 8-MW solar power generation and battery sys- tems at the mine, located east of Laver- ton in Western Australia. Gold Fields Executive Vice President Australasia Stuart Mathews said, "We ex- pect the renewable power microgrid will be up and running at Granny Smith by Q4 2019 and it will be a welcome addition to our suite of on-site energy solutions across other operations which will enable us to reduce our carbon footprint." Construction of the renewable energy system is to begin in May and, when com- pleted, will be one of the world's largest hybrid off-grid microgrids and integrated with Aggreko's existing 24.2-MW natural gas generation. Aggreko AusPac Managing Director George Whyte said the solar, thermal and battery storage assets will be integrated and managed by Aggreko's control software platform. "The solar-plus-battery system is projected to reduce fuel consumption by 10–13% and produce about 18 GWh of clean energy per year," Whyte said. While the solar PV will reduce the need to run thermal generators, the bat- tery plant will provide essential services such as spinning reserve displacement, PV ramp rate control and transient volt- age/frequency support. Stable Sourcing As RE technologies and systems prolif- erate, power systems will need to adjust accordingly to better accommodate inputs from variable renewable energy (VRE) sources like solar and wind plants by im- proving system flexibility, according to a report issued by REN21, a global RE poli- cy network. However, renewables technol- ogy is evolving to improve ease of inte- gration, and state-of-the-art solar PV and wind energy generators can provide a vari- ety of relevant system services to stabilize the power grid, said the organization. Adding digital intelligence Dtect By adding Dtect to torque limiting couplings, you get real-time monitoring of the driveline per for- mance, productivity and status. The system is designed to predict potential problems, protect the driveline and prevent costly downtime. Visit us at Bauma in Munich, Germany from April 8 – 14, 2019 Hall C2, booth #239

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