The Eskom board of directors gave approval in March to develop Tubatse, until recently called by the provisional name Project Lima. (HNN 4/4/08) The pumped-storage project is planned for the escarpment between South Africa's Nebo Plateau and the Steelpoort River Valley.
Eskom must acquire the operating license from NERSA before proceeding to the next phase of the project, actual implementation. The current review is of the last phase of an ongoing application process. Eskom estimates the project will go on line in late 2015 for an estimated cost of 10.2 billion rand (US$1.02 billion).
Tubatse's upper reservoir would be built at the top of the Thaba ya Sekhukune escarpment near the town of Sehlakwane. The lower reservoir would be within the Steelpoort River Valley and would be fed by a pipeline from De Hoop Dam.
The upper dam is a 31-meter-tall, 3,750-meter-long concrete-faced rockfill dam. The lower dam is a 51-meter-tall, 1,600-meter-long zoned earthfill structure with an impervious core. The underground powerhouse is to contain four 375-MW pump-turbines.
Eskom designed the lower reservoir to be off channel, reducing the overall waterway length of the project, improving hydraulic efficiency and lower capital costs of development.
Tubatse's environmental impact assessment has been completed, with the project receiving a positive environmental authorization from the Department of Environment and Tourism in October 2007. Its feasibility study was completed in November 2000.
Eskom is already developing another pumped-storage project, 1,368-MW Ingula, on the border of South Africa's Free State and KwaZulu-Natal. In September it named Voith Siemens Hydro Power Generation to supply complete electro-mechanical equipment, including four pump-turbines of 342 MW each, four motor-generators, and complete automation and control systems. (HNN 9/3/08)