In an emerging CSP market such as South Africa, one of the many challenges developers face is siting the project based on acquiring accurate Direct Normal Irradiation data, as optimal siting of CSP plants is a key component to plant efficiency, and ultimate profitability.
DNI plays a role because it is used to predict the output of concentrated solar power stations as the receivers or heliostats track the sun throughout the day.
In South Africa progress has been made by the Centre for Renewable and Sustainable Energy Studies at Stellenbosch University, who have been working in partnership with GeoModel Solar to analyse the measured data to predict the solar resource available at the Solar Park. The result of this is that the 5GW solar park and corridor that the South African government is planning to build near Upington in the Northern Cape is considered as having amongst the best DNI in the world.
The long-term average DNI at the site was calculated to be 2 816 kWh/m2 per annum. In Spain the typical DNI values where CSP plants are built varies between 2 000 and 2 200 kWh/m2 per annum. In CSP plants in the USA the DNI is in the order of 2 700 kWh/m2 per annum . The Northern Cape has now been identified as an area with an exceptionally high solar irradiance, higher than the areas in North Africa where the Desertec project may be implemented. The interesting outcome has been that even though Upington has very high DNI, there are areas towards the west of Upington with even higher DNI values.
The solar park is one of the Energy Department’s flagship renewable projects, and Fluor is assisting the State-owned Central Energy Fund to commission a feasibility study on the project, for which government had made R18-million available.
The site is located very close to Eskom’s planned 100 MWe CSP station at Olyvenhoutsdrif, which would be commissioned in 2016.