Engineering News, 24 June 2011
The 5 000 MW solar park, which government is planning to build near Upington in the sun-drenched Northern Cape, would have some of the best solar resources in the world, the Stellenbosch University said on Friday.
The long-term average direct normal irradiation (DNI) at the site was calculated to be 2 816 kWh/m2 a year and the average optimal tilt irradiation (OTI) 2 555 kWh/m2 a year.
DNI is used to predict the output of concentrated solar power (CSP) stations where the receivers or heliostats track the sun throughout the day, while the OTI value predicts the yield of stationary, or fixed tilt, photovoltaic panels.
The university said that the averaged values at the Upington site were very high, comparing it to Spain, which hosts a number of CSP plants, where typical DNI values were between 2 000 kWh/m2 and 2 200 kWh/m2 a year and North America where DNI was in the order of 2 700 kWh/m2 a year.