Decision support tools are essential instruments in making informed choices and decisions. These tools can be found in all organizations including governments and multi-corporations to even small businesses. The underlying knowledge used to build these can span from the areas of pure engineering and economics, etc., to diverse interdisciplinary fields. Systems thinking is one of these multi-disciplinary approaches which looks at problems and projects through a holistic manner. Energy projects involve broad socio-environ-economic concerns, and system thinking seems to be the right approach to take. One of the essential systems thinking tools for policy and decision-making is System Dynamics and it was used for over 50 years. System dynamics is based on causal variables and inferences that change over time. This book chapter introduces system dynamics as the tool and goes step by step to develop a methodological framework for the techniques required to approach problem solving using this tool. At the end of this chapter, you will be able to think of an energy problem in terms of system thinking and approach it to address issues that are unique and specific depending on the available knowledge and within the various constraints.