Ingula Pumped Storage Scheme, South Africa

Ingula Pumped Storage Scheme (Ingula PSS) is located 23km north-east of Van Reenen’s Pass on the border of Free State and KwaZulu Natal in South Africa. The facility will generate power for the national grid. Van Reenen’s Pass was selected out of three sites that were shortlisted from 90 locations.

South Africa requires 40,000MW power by 2025. Ingula is one of the projects being constructed to meet the future demand.

The scheme is being built on a 9,000ha site by state-owned Eskom at a cost of R8.9bn.

The work on the facility began in November 2007 and is expected to be complete by 2012. It will be fully operational by 2013.

Development of the pumped storage scheme was proposed in 2002 and was initially called the Braamhoek scheme, named after a tributary of the Klip River. In March 2007, the scheme was renamed Ingula, which means the cream on the surface of milk. The basic design of the scheme began in 2004, when it was given environmental clearance.

Scheme design

The scheme construction encompasses two dams – the upper and lower reservoirs; a powerhouse, two tunnels that carry water from the reservoirs to the powerhouse, access roads and transmission lines.

The upper dam of Ingula PSS, named Bedford Dam, is located in the secondary of Wilge River that flows into the Vaal River system. The dam is 810m long and 40.9m high. It also has a 100m-long emergency spillway, a dam crest with elevation of 1740.6m and 8m crest width.

The roller lower dam, named Braamhoek Dam, is situated in the secondary of Klip River that flows into the Thukela River. The length and crest width of the dam are 331m and 5m. The dam is 38.6m high and has a 40m long crest. The 0.5m dam wall height holds flood inflows to avoid 1:200-year flood dam spill.

The two dams are situated 4.5km apart. In order to generate electricity during high energy consumption, the water will be pumped from the upper dam to the lower dam. The process will be vice versa during low energy consumption period. A generator is being installed to draw more electricity to drive the water back to upper dam, during the low energy consumption period.

The dams are designed for a water capacity of 22 million cubic metres and have underground waterways. The underground powerhouse comprises four 333MW pump turbines and will generate a total of 1,332MW of electricity. The power house is 172m long and has a height of 40m while its average width is 23m. The water to be stored in the dam will be drawn from the rivers.

Capacity

Ingula PSS has the capacity to generate 1,332MW of electricity. A 70m³/s of maximum discharge capacity is being provided by the Bedford Dam at full supply level, while 52m³/s at minimum operating level. The Braamhoek dam provides a maximum discharge capacity of 74m³/s and 2.3m³/s at high flow and low flow outlets respectively.

Environmental Impact

Being a hydel power project, the process of generating electricity in the Ingula pumped storage scheme will lead to no emissions into the environment. However, South Africa being a water scarce country, the construction of dam near the river could effect the lives of common people by depleting water in the region.

In 2004, Eskom has partnered with BirdLife South Africa (BLSA) and Middlepunt Wetland Trust (MWT) to mitigate the adverse impact of Ingula on the environment. The partnership also monitors the effect of the construction on birds, veld management, eradication of alien plants, wetlands monitoring and community upliftment.

The partners have also taken measures to protect birds – especially threatened birds.

Construction

As of July 2009, excavation on the left side of the upper dam has been completed while that on the right side is in progress. Pipelines connecting the dam with the river are being laid. Excavation for the lower dam is complete and pipelines have been installed.

Construction of access roads was a pre-requisite for the scheme to get authorisation. Grinaker LTA was awarded a contract to build 67km of roads. Around 12km was tarred with 15km of road on base layer. The construction started in January 2007 and was completed by 2008.

Murray Roberts began construction of a 1.2km exploratory tunnel in August 2005 and completed it in 2007. The €19m contract for construction of the main access tunnel was awarded to CMC Mavundla, a consortium of South African and Italian companies. The main access tunnel is 1,275m long with a height of 8.7m and was excavated up to 482.90m.

Eskom has awarded a contract to B&E Quanza group for water supply, sewage treatment, small access roads and building of temporary Eskom offices.