This paper presents the work developed under the framework of a research project "Transition Scheme through a Sustainable-Energy System in Sahelian Countries". The project ran between 1997 and 2001, involved several European Union and African entities and was coordinated by the New University of Lisbon. It was financed by the Research Directorate under the framework of INCO DC Programme. The researchers were trying to answer a multiplicity of questions and to find realistic solutions for the transitional period for one of the most problematic regions of the World, namely the Sahel Region. The present paper intends to highlight some of the aspects related to the energy affordability, e.g. income, spending, indirect costs of energy, and energy subsidies that have been revealed during the study. It considers "customer-sustainable" and "customer-affordable" energy structures and proposes measures for energy-affordability enhancement. (C) 2003 Elsevier Ltd. All rights reserved.