This paper assesses the different levels of uncertainty that affect the analysis of informal urban settlements and the implementation of upgrading policies, with a specific focus on electrification. The rapid growth of informal settlements in the cities of the Global South poses serious challenges to the management of energy systems, particularly when it comes to the electricity grid. Informal urban settlements are characterized by the lack of urban planning and low or absent provision of public services. Exponential population growth increases the complexity of urban planning. An inadequate understanding of uncertainty can undermine the effectiveness of informal settlement upgrading and deepen social inequalities. Based on the case study of the Enkanini settlement in Stellenbosch, South Africa, this paper probes three levels of uncertainty: (i) methodological uncertainty associated with the challenge of estimating energy demand and demographic changes, (ii) technical uncertainty associated with the expansion of the electric grid and securing revenues, and (iii) epistemological uncertainty associated with the definition of the relevant problems and pertinent solutions for informal settlements. The paper highlights how the focus of technical uncertainty displaces the debate on the socio-political challenges of informal settlement upgrading.