The author reviews trends in rural electrification over the past 30 years in Sub-Saharan Africa. In particular, it is shown that motivations for rural electrification programs have evolved significantly over the years, following changes in development paradigms. The author finds, however, that knowledge of the impact of this has only marginally improved: low connection rates and weak productive utilization identified in the 1980s remain true today, and impacts on such dimensions as health, education, or income, though often used to justify projects, are largely undocumented. Indeed impact evaluations are methodologically challenging in the field of infrastructures and have been limited thus far. Nevertheless examples of recent or ongoing impact evaluations of rural electrification programs offer promising avenues for identifying both the effect of electricity per se and the relative effectiveness of approaches to promoting it.