It is widely recognised that access to and supply of modern energy play a key role in poverty alleviation and sustainable development. The emerging concept of energisation seems to capture this idea; however, there is no unified definition at the point of writing. In this paper, the aim is to propose a new and comprehensive definition of the concept of energisation. The chronological development of this concept is investigated by means of a literature review, and a subsequent critique is offered of current definitions and usage of the concept. Building upon these first insights, two planned cases of energisation in post-apartheid South Africa are contrasted to an unplanned one: they are the national electrification programme, the integrated energy centres initiative, and a wood fuelled local economy in Khayel itsha, Cape Town's biggest township. Especially the latter case, based on original data collection by the authors, provides a new understanding of specific elements affecting energisation. Finally, a new and detailed definition of the concept of sustainable energisation is developed by systematically reiterating three key elements: the target group, the concept of energy services, and sustainable development. (C) 2009 Elsevier Ltd. All rights reserved.