A key advantage of renewable energy is that it can power the energy needs of mining operations in remote areas, where the cost of building the infrastructure required to hook the mine up to the grid network or building a conventional power station would be significant. By having a dedicated off-grid renewable power source, a mining operation can meet all its energy requirements from green sources and make significant cost savings in the price it pays for its electricity. Take for example the Canadian gold-mining company B2Gold’s plan to develop and install one of the world’s largest off-grid solar and battery power systems at its Fekola mine in Mali. The US$38m project will consist of a 30 MW solar plant with 13.5 MWh battery storage, to be integrated into the existing power plant which runs off HFO²¹.
The development of micro-grids in areas with a high concentration of minerals where several mining operations are in place. Micro-grids benefit from being disconnected from the main grid, thereby allowing the operator greater control over the power output, which is essential in any mining operation where the supply of power is key. The recently developed Agnew microgrid in Australia developed by EDL (a renewable energy company) and local mining company Gold Fields, is an excellent example of this. With an array of five 110m-high wind turbines, each with 140m-wide rotor spans, plus over 10,000 solar panels, the grid has a capacity of 22 MW and is already supplying the majority of the power to the Agnew gold mine, achieving as much as 78% of the total power consumption of the operation (the remaining power being generated by its on-site 24.2 MW natural gas generator)²². Key to the success of the Agnew micro-grid is the technology developed by EDL to harmonise the output of each generation source in a manner that optimises the output from the renewable energy sources and only uses the natural gas generator where necessary. Such technology would be far more difficult to implement in a mine attached to the national grid where the operator would not have autonomous control over the system balances. Gold Fields also has plans to install an additional twelve wind turbines at its nearby Granny Smith mine, which already benefits from 8 MW of solar panels with a 1 MW/2 MWh lithium-ion battery, that it intends to connect to the Agnew micro-grid²³.
