Efficiency and costs of different concentrated solar power plant configurations for sites in Gauteng and the Northern Cape, South Africa

Abstract

Concentrated solar power (CSP) plants can play a major role in the future South African electricity mix. Today the Independent Power Producer (IPP) Procurement Programme aims to facilitate renewable energy projects to access the South African energy market. In spite of this incentive programme, the future role of CSP plants in South Africa has yet to be defined. Using hourly irradiance data, we present a new method to calculate the expected yield of different parabolic trough plant configurations at a site in each of Gauteng and the Northern Cape, South Africa. We also provide cost estimates of the main plant components and an economic assessment that can be used to demonstrate the feasibility of solar thermal power projects at different sites. We show that the technical configurations, as well as the resulting cost of electricity, are heavily dependent on the location of the plant and how the electricity so generated satisfies demand. Today, levelised electricity costs for a CSP plant without storage were found to be between 101 and 1.52 ZAR2010/kWhel, assuming a flexible electricity demand structure. A CSP configuration with Limited Storage produces electricity at costs between 1.39 and 1.90 ZAR2010/kWhel, whereas that with Extended Storage costs between 1.86 and 2.27 ZAR2010/kWhel. We found that until 2040 a decrease in investment costs results in generating costs between 0.73 ZAR2010/kWhel for a CSP plant without storage in Upington and 1.16 ZAR2010/ kWhel for a configuration with Extended Storage in Pretoria. These costs cannot compete, however, with the actual costs of the traditional South African electricity mix. Nevertheless, a more sustainable energy system will require dispatchable power which can be offered by CSP including storage. Our results show that the choice of plant configuration and the electricity demand structure have a significant effect on costs. These results can help policymakers and utilities to benchmark plant performance as a basis for planning.