South Africa - Enlight the rainbow nation

The technically feasible hydropower potential of South Africa is about 14,000 GWh/year, of which about 90% has already been developed. 3,586 MW of hydropower including 2,832 MW of pumped storage capacity produce some 4,750 GWh of electrical energy per year, about 2% of national supply. Feasibility studies for new pumped storage power are now ready and some 100 MW of small hydropower could also be developed.

Furthermore, there is the potential to harness marine energy along the coast; for wave power in the south and southwest, and for current tidal turbines in the east.

ANDRITZ HYDRO 

ANDRITZ HYDRO has a long history in South Africa, with a local company operating from Johannesburg since 1979. More than 750 MW have been delivered to the country to date and the company was involved in major hydropower projects, such as PSPP Drakensberg, PSPP Steenbras and HPP Vanderkloof.

ANDRITZ HYDRO has a partnering contract with national utility Eskom for replacement of the control systems in their hydropower plants. Under the frame of this contract ANDRITZ HYDRO is currently executing the order for the 400 MW Pal­miet pumped storage power plant.

Power Recovery Turbines in Mines

About 18% of the electricity demand in South Africa comes from the mining industry. Exploitation of minerals such as gold and platinum from deep mines require large volumes of cooling water as temperatures in the working areas can exceed 40°C. To reduce the temperature, cooling water from a central refrigeration plant at the surface is brought down to depths of about 3,000 m. The warmed water is then pumped up to the refrigeration plant for re-cooling, a process which requires about 14% of the overall electricity demand of the mine. Energy costs and friction losses can be partly compensated for by the installation of power recovery turbines. ANDRITZ HYDRO has already installed more than 50 underground energy recovery turbines with a total capacity of over 80 MW in various mines in South Africa.

HPP Stortemelk

Autumn 2016 saw the Preliminary Acceptance Certificate (PAC) signed for the new hydropower plant Stortemelk. Developed for the customer Stortemelk Hydro (RF) (Pty) Ltd. by Renewable Energy Holdings (REH), Stortemelk is located near the town of Clarens in the Free State Province. Aurecon, South Africa provided the engineering, procurement, and construction management services for the implementation of the project.

The scope of supply for ANDRITZ HYDRO comprised the complete electro-mechanical equipment, including one 4.4 MW vertical shaft compact axial turbine (CAT) with a runner diameter of 2,350 mm, the synchronous generator (with consortium partner), the complete control and SCADA-system, and the MV switchgear. During the commissioning phase, the strict South African grid code describing the required behavior of a connected generator during system disturbances was also successfully implemented. The new power station will produce about 25 GWh of renewable energy per year.

Johannesburg – Submersible Pumps

Beneath Johannesburg numerous abandoned shafts from former gold mines have created a problem for city planners. Water has been entering these shafts and a lake of heavily contaminated water has formed under the city. In the spring of 2014, two double-suction submersible motor pumps from ANDRITZ with an average daily flow of about 60 million liters were installed to bring the water level down again.

ANDRITZ offers a pump series specially conceived for the difficult mining conditions. The design is based on ANDRITZ' proven HDM (Heavy Duty Mining) technology, which uses the concept of a double-suction pump with a service life of 10 to 15 years. The engineers at ANDRITZ developed an innovative design based on encapsulation of the submersible motors to fend off the aggressive acid. This encapsulation prevents water from penetrating and attacking the components inside. Two pumps were delivered and after successful operation more deliveries are in progress.

Author: Wilhelm Karanitsch