ENERGY
CAN (AND SHOULD) MINES GO OFF THE GRID? By Trevor Crighton
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enewable energy plants won’t allow mines to go completely offgrid just yet – but will allow them to make significant reductions in emissions and take substantial pressure off Eskom. “The increase of the generation licensing threshold from 1MW to 100MW is one of those rare ‘stroke of the pen’ reforms that unleashes enormous financial, economic and environmental value,” says Sedibelo Platinum Mines chief environmental, social and governance (ESG) officer Lael Bethlehem. “It’s an extraordinary reform that provides relief to Eskom and has a spin-off in terms of supporting South Africa’s growing green economy.” Norton Rose Fulbright head of energy Matt Ash says mines can take advantage of the change in two ways – with embedded behind the meter generation or distributed generation. “In the case of the former, the generation site would be situated on land owned by the mine and near to the operation where it is required,” he says. “That’s easier than the latter, where the generation facility is located remotely from the mine.” Distributed generation with wheeling is a financial, not physical, transaction, with an independent power producer (IPP) being
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SA MINING
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credited for the electrons injected into the network on its accounting system and the offtaker being entitled to take them off the network at the other end, with adjustments made to supply. Ash says from a behind the meter point of view, the change in the threshold means that mines wanting to do so can simply get on with it. But there’s a challenge for those looking to operate a distributed model. “The problem is that the Eskom network is physically incapable of having hundreds or thousands of IPPs feeding energy into it, without significant risk of network destabilisation – which could happen in a nanosecond and see the entire country in the dark for two to three weeks should the network fail.” Another challenge in using renewable energy is intermittency of supply, so if the load were to suddenly disappear – or power unexpectedly become available – it would quickly destabilise the national grid. “These distributed connections wouldn’t all be possible until there is a set of rules around balancing the grid that is agreed on by all players, also with penalty consequences for those who breach the rules,” says Ash. “That said, we’re doing a lot of work with mines that have a mix of embedded and distributed generation, coupled with some battery storage systems
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to deal with intermittency – they’re voting with their feet and moving forward with their plans.”
GOLD FIELDS’ HEAD START
Gold Fields is proceeding with building its own R715-million generation plant at South Deep, Johannesburg, which should be commissioned in the third quarter of this year. “Our application for construction of a 40MW solar plant was approved by the National Energy Regulator of South Africa in February 2021. When the increase in embedded generation was announced, South Deep carried out a further optimisation study which revealed that upgrading the solar plant by an additional 10MW would unlock maximum value within the mine’s current ability to make use of additional power generated,” says Martin Preece, SA’s executive vice president of Gold Fields. “Taking this into account, the change of scope will increase capacity from 40MW to 50MW and allow for future expansion to 60MW within the existing environmental authorisation.” The plant will increase power generation from 94GWh per annum to 103GWh per annum – 24% of South Deep’s annual electricity consumption – and reduce its CO2
