ngula pumped storage scheme Unit 3

Eskom’s Ingula Pumped Storage Scheme Unit 3 was successfully synchronised to the national electricity grid over the weekend, making it the final unit to be connected.

Ingula connections

Ingula Unit 3 was synchronised to the national grid on 6 March 2016 and supported the grid until 6 April 2016 when an electrical incident occurred, the South African utility explained in a statement.

“After almost 500,000 man-hours of work, without any safety incidents, the team completed the repair and has synchronised the unit back onto the national grid,” the parastatal said.

In August, Unit 2 of the Ingula Pumped Storage Scheme came into commercial operation becoming the second generator after the power plant’s Unit 4 to have completed all the prerequisite quality assurance tests.

Launched in July by President Jacob Zuma, Ingula’s Unit 4 was the first to come into commercial operation.

At the time of the Unit coming online, Eskom noted via a statement that the commercial operation of these two units mark a key milestone towards the full commercial operation of the entire Ingula Pumped Storage Scheme ahead of the scheduled deadline of mid-2017.

The Group’s CEO, Brian Molefe, commented: “The commercial operation of Unit 2 will add an extra 333MW into the national [grid], and this will enable us to ensure security of power supply to South African homes and businesses.”

Molefe added: “Besides being a catalyst for economic growth, a stable power supply will also enable Eskom, together with municipalities, to rollout electrification programmes to make life easier for millions of households who currently rely on other fuel sources for domestic cooking and heating.”

Peaking power

Ingula is part of Eskom’s Peaking fleet of power stations, it can respond to demand increases on the grid within two and half minutes.

Upon completion Ingula will be Africa’s newest and largest pumped storage scheme and the 14th largest in the world, according to Eskom.

Explaining the technology setup, Eskom notes: “Ingula’s four units are located 350m underground in the world’s largest machine hall in mud-rock. To turn the more than 500 ton rotating mass of the generator rotor and turbine, water is released from Ingula’s upper dam, Bedford Dam, situated 460m higher and 2km away.

“Water rushes down to the turbines at around 60km per hour with enough water passing through each turbine to fill an Olympic-sized swimming pool in six seconds. Rotating at 428 revolutions per minute, each unit will produce 333MW, a total for the station of 1,332MW.”