Prof Rosemary Falcon, in the energy session during the recent CSIR Conference in Pretoria, outlined the three-legged requirement for energy sustainability – namely, security, affordability and environmental protection. Security is the most serious concern to the US (hence war in the Middle East), environment is of most concern to those in Europe (due to the density of population), but affordability is the primary issue in South Africa – given that this country has high unemployment, extensive poverty and a high proportion of the population without energy. This country is fortunate to have a good security of supply (coal, uranium, sun and sea) and no serious threat of environmental legislation (currently). This being the case, assurance of sufficient energy to meet the rapidly increasing demand and at the lowest possible cost does suggest that all energy sources need to be phased in at appropriate times, and that the current urgent need dictates an interim phase whereby the tried and trusted systems of coal- and nuclear-fired power stations are required in the short and medium term.