Gold Reef City hydro power idea ‘can be done’

Cape Town – Turning Gold Reef City’s abandoned mine shafts into a pumped storage hydroelectric scheme is an idea worth pursuing, said an executive with 40 years’ experience in the mining industry.

In fact, Solid Pump Recon MD Jan King wants to develop about 20 dormant mine shafts into pumped storage hydroelectric power stations that could produce between 10MW and 50MW of electricity each. If his dream becomes a reality, that would be a maximum of 1 000 MW of baseload renewable energy - gold in the energy sector.

Responding to a Fin24 question about whether hydro power could be developed using this method, King said he is looking for research and development funding to pursue the idea.

READ: How Gold Reef City could end load shedding

“Once I have scientific confirmation proving that it can be done, I will apply to be an independent power producer,” he said.

“Gold Reef City is an option,” he said. “But there are at least 20 dormant shafts where it can be done.”

King said that because the tunnels are already there, the construction period would be a fraction of any other new build project.

The only hydropower scheme under construction in South Africa is Eskom’s Ingula pumped storage scheme in the Drakensburg, which will generate 1 332MW. It was supposed to be completed in 2013, but a fossil find that predates the dinosaur and other factors have delayed it to 2017.

INFOGRAPHIC: Ingula's planned scheme

Source: Eskom

Small hydro power sources have been identified as one of the renewable energy technologies that SA can use, according to Urban Earth.

“At present 15 MW of electricity is generated from small hydro power sources less than 10 MW in South Africa,” it explained. “8 MW  of Eskom’s total hydro power generation capacity of 661 MW is generated from Eskom small hydro power sources.

“These are First Falls (6 MW) on the Umtata River and Ncora (2 MW) on the Ncora River. Municipal small hydro power installations contribute 4MW to South Africa’s electricity generation and one privately owned small hydro power installation generates 3MW.”

Eskom has three types of hydroelectric power stations; conventional reservoir (360MW at Gariep and 240MW at Vanderkloof), run-of-river (Colley Wobbles, First and Second Falls and Ncora) and pumped storage schemes (400MW at Palmiet and 1000 MW Drakensberg).

"The secret lies in eliminating or reducing the cost of pumping the water back to surface in order to recycle to make it a constant supply," King said in a planning document.

GRAPH: Jan King's schematic of a mine pumped storage hydroelectric shaft

Expert questions idea

Wim Jonker Klunne, a sustainable energy and climate change expert, told Fin24 that mine shafts are indeed excellent locations to build pumped-storage schemes, "but that is something different from what traditionally is meant with hydropower".

"Pumped storage schemes, as the name suggest, are used for storage of electricity, in the form of water that can be converted into electricity at a later stage," he said.

"At pumped storage schemes, electricity is being used to pump water to higher altitudes when there is a surplus of electricity, to release the same water through a hydro turbine to generate electricity when there is a electricity shortage.

"Effectively, pumped storage is a type of battery. Important to keep in mind is that this storage comes at a costs: pumping the water up typically costs more electricity than is generated when the water is released. Typical efficiencies of pumped storage schemes are around 70%,

"Although SA has a problem during the evening peak in terms of available electricity, the current pumped storage schemes by Eskom are not used at full capacity as there is simply not enough electricity to pump the water during off-peak times.

"Hence, converting mine shafts into pumped storage will not solve the problem," he said.

Other Fin24 users were not as certain about mine's being turned into hydro power stations. Read their views now.

* Is the Gold Reef City idea a pipe-dream or a good idea? Tell us why.

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