The impact of climate change on wind and solar resources in southern Africa

Climate change is an issue that requires global attention and co-operation. As climate science develops an understanding of changes to the future climate state, policy makers and engineering project planners beg to know what claims can be made on the subject with a reasonable level of confidence. A common and popular mitigation strategy for reducing emissions is to build away from carbon intensive electricity production to clean energy sources like the energy produced from wind and solar irradiation. These sources themselves are climate dependent. In this study, we present a method to estimate the climate change impact on wind and solar resource potential which builds on previous studies that take a risk-based approach. The assessment combines climate projection output from the Integrated Global Systems Model, which introduces emissions and climate sensitivity uncertainty, with 19 Global Circulation Models available from the Coupled Model Intercomparison Project phase 3. Southern Africa, specifically those in the Southern African Development Community, is used as a case study. We find little agreement between Global Circulation Models and emission scenarios, resulting in a median change close to zero by 2050 in the long-term mean of both wind speed and solar radiation (used as an indicator of change in electricity production potential). Although the extreme possibilities range from about -15 per cent to +15 per cent change, these are associated with low probability. These projected results in the long-term mean climate - and their associated probabilities - stay true to the limitations of state-of-the-art climate system models and are apt to be useful for policy and engineering planning.