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Eskom – Ingula Pumped Storage Scheme

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Behind schedule, over-budget and dogged by delays and damages, Eskom’s controversial Ingula hydroelectric pumped storage power station finally came online in January of 2017. The station provides 1,332MW, a solid contribution of South Africa’s endemic power shortages. But how much will it help towards solving the country’s power needs?

Ingula Pumped Storage is a hydroelectric power plant straddling the borders of the KwaZulu-Natal and Free State provinces in South Africa, in the Little Drakensberg mountain range near Van Reenen.

It consists of two dams, 4.6km apart, connected to a power station by tunnels. The Upper Bedford dam, which is around 460m above the rest of the plant, supports a reservoir of around 22,400,000m3 of water storage capacity, of which around 19,200,000m3 is usable for power generation.

When the station is switched on, water flows from the Upper Bedford dam through a 1.2km long headrace tunnel to a power house, which holds four 333MW reversible Francis pump-turbines, and then down a 2.5km long tailrace tunnel to the lower reservoir, which is held up by the Lower Bramhoek Dam. The system can begin responding to National Grid power shortages in less than two minutes, and is the fourteenth largest of its kind in the world.

Easing the strain

Pump-loading projects like Ingula serve a very specific purpose in the national power grid: meeting peak demand and supply during times of high strain. It doesn’t actually generate a great deal of net power. Once the water has run down to the lower reservoir, it must then be pumped back up to the upper reservoir ready for the next use.

Thanks to economies of scale, this can be done in the early hours of the morning when conventional nuclear and coal-fired power plants are producing energy and demand is low, but ultimately this means that the project serves as less of a means of generating power than it does of storing it on a massive scale for use during peak time.

The project was designed and built by Eskom, and cost a total of around R35 billion (around US$2.4 million). One obstacle during the project’s construction run was its ballooning costs, which spiraled from R8.9 billion thanks to contractor inefficiency, corruption and unplanned expenses. Some South African media have laid this overrun at the feet of CMI Joint Venture, an Italian contractor with a reputation for unreliability, but others point to PG Mavundla Engineers, owned by a friend of President Zuma.

Costs aside, construction began in 2005 and the plant was planned to come into operation in 2013, but delays and overruns stalled the first power production until 2016. Further problems came when the number three turbine was damaged during synchronization testing, delaying its activation by six months while repairs were made. Eskom’s generation division runs the plant on a commercial basis.

 Saving shed loads

Speaking at the project’s launch, Eskom’s Interim Group Chief Executive Matshela Koko said, “the commercial operation of Unit 3 completes the Ingula pumped storage scheme project. This will further strengthen security of power supply to South African homes and businesses. I am thrilled that we are on track to deliver all New Build projects. This achievement would not have been possible without the hard working team at Ingula and strong executive leadership in Eskom.”

Other South African sources hailed the project as a solution to the dreaded “load shedding”. This has paralyzed the economy for several years as existing power plants proved unable to keep up with peak demand. Although the Ingula project was extremely expensive and well over budget, its completion sees Eskom in a position of much greater financial stability than when it was started. In a statement to the South African parliament, Eskom’s chair Ben Ngubane described Eskom’s current position as “almost a miracle”, noting that “we have stabilized Eskom coming from a very poor base with a fleet that was faltering. Plant availability is 80% and more, which is almost a miracle, considering where we were a year ago.”

The Ingula plant will relieve the load on expensive and environmentally unfriendly open gas cycle turbines and diesel generators, which supported peak time generation during the load shedding crisis. As a result, Eskom’s generation costs have dropped to just R0.09 billion in 2016/17, a major saving.

South Africa’s power supply problems are still not insignificant, and projects like Ingula are highly situational. They are only helpful as a “booster” in times of high stress, and at other times rely on other forms of power generation or excess power to pump the water back up again.

Projects as complex and costly as Ingula are likely to run into issues. However, it is now forming part of a solution to a complex problem, and from a potential disaster an important source of power for South Africa appears to have been salvaged.