While mining operations require reliable power on a continuous basis, whether in remote locations or in developed areas, load-shedding, poor-quality power and weak grids are forcing mines to consider alternative sources of electrical energy.

juwi South Africa MD Greg Austin believes electricity wheeling can be a key alternative and should be seriously considered as a material solution to the energy requirements of mines in South Africa.

“The mining and materials industry is not in the business of energy production. [They], therefore, won’t take on the risks involved in developing a solution, as this is not their core business. [However], the emergence of independent power producers (IPPs) and the possibility of power wheeling – possibly in conjunction with storage – may [satisfy] the need for a reliable supply of energy,” Austin noted in a press statement released last month.

He illustrated that, for example, a solar photovoltaic (PV) plant operating in Prieska, in the Northern Cape, or a wind farm operating outside Cape Town, in the Western Cape, could supply a mine in Rustenburg, in the North West, by wheeling the electricity through State-owned power utility Eskom’s transmission grid, and through the Rustenburg distribution grid, before it reached the mining customer.

Austin also added that storage, in general, held advantages for the mining industry. However, in the context of a grid-connected mine, the primary advantage is the ability to shift loads, for example, where cheap night-time electricity from the grid is stored to provide peak power when required.

A key example is a $40-million project involving a 0.6 MW solar hybrid system, which the juwi group developed, designed and constructed to fully integrate with the existing 19 MW diesel-fired power station at the DeGrussa copper and gold mine, in Western Australia. juwi Australia made it possible to configure the PV plant to provide the full load during the day, with the generator sets running at night and when there were low solar radiation levels.

Oversizing the PV system to increase the mine load feeds energy into the storage system, which handles short variations in the PV output and short variations in the load, Austin noted.

The two key challenges regarding the wheeling of power are balancing generation and consumption, and determining the cost of wheeling and reasonable charges, as these formed the basis of most of the commercial elements related to wheeling, Austin emphasised.

“The lack of clarity on charging, regulations, open access and cross-subsidy are . . . on the table for discussion . . . To make this model operational, electricity regulations need to be designed to remove specific barriers to participation of developers and intermediaries who play an important role in the propagation of such systems,” he stated.

Austin further noted that, the National Energy Regulator of South Africa had drawn up guidelines and regulations covering the technical and charging aspects involved, and that the costing model was highly complex.