This research proposes a "Dynamic Energy Systems" (DES) paradigm- a Decision Support Systems Framework using a System Thinking (ST) and System Dynamics (SD) approach for sustainable energy planning in a Developing Economy (DE) using developing Botswana economy as a case reference. Many of the DE is currently undergoing dramatic changes in socio-economic policies such liberalisation of the energy markets, financing of energy projects and the incorporation of previously grounded externalities such as the environmental implications of energy projects. The research begins by reviewing the literature on the underlying dynamics of sustainable energy development (SED) in the DE. It further examines the inherent limitations of traditional planning tools such as optimisation, econometric and general simulation models for energy planning and policy formulation in DE. It argued that the advocated strength of optimisation tools is significantly impaired in the DE where economic, social and environmental objectives are multidimensional, complex and hence seldom given a clearer definition. Traditional energy planning tools are inappropriate in DE as they focuses on the present decision without identifying how past policies created the present complexities. This research also argued that traditional modelling approach fail to demonstrate the policies that would guide future decisions. Further, lack of reliable data and the absolute determination of the objective function in many DE undermines the suitability of both econometric and optimisation models. Given the inherent systems structure, current trends and future forecasts in the DE, there are complex implications that need addressing in the applications of traditional planning tools to sustainable energy planning. The unsuitability of traditional tools to DE is rooted in the welldocumented socio-economic, political and technological differences, as compared to those of the Organisation for Economic Co-operation and Development (OECD) nations.The past energy development trends witnessed in the OECD nations contradict the notion of SED. It is therefore paramount that energy planners and their advisers in DE integrate these complexities in the applications of traditional planning models. Hence, DE requires a new paradigm for SED. DES modelling and methodological approach facilitates the design of policy rules that govern complex decision-making. It demonstrates how past policies created the current crises. The use of DES enables the modelling of complex energy issues, and enhances understanding of the dominant system characteristics that causes energy systems instability in the DE. This research maintains that the major impediments to SED in the DE are appropriate technology; social organisation; environmental (energy) resources and investment directions. The proposed methodology focuses on analyses of the dynamic forces that impinge on energy systems and seeks to improve the decision making process. This research fills an important gap in the literature by demonstrating the merits of DES as a framework that permits focusing on the holistic structure identifiable within an energy system in the DE. The research also identifies the underlying differences of sustainable energy planning in DE as compared to those of the OECD nations.