Concentrated Soar Power (CSP) systems can be equipped with capacity to store heat energy enabling generation at night or other times when there is little or no solar irradiation. Proposals for high penetration or 100% renewable energy supply systems therefore often envisage major dependence on the CSP component of the system to help solve the intermittency and storage problems. However there is little evidence on the extent to which this can be done when solar radiation is poor. This study draws on some recently available information to clarify the issue with respect to the proposed Aurora plant for South Australia. It finds that there would be periods of a week or more in which little energy was being produced, and therefore that CSP is unlikely to be capable of making a significant contribution to the storage task in unfavourable conditions.