The Armed Forces are heavily reliant on fossil fuel, but also largely affected by the development of the surrounding society. This rises a demand to increase knowledge on how to design a future system for propellants and energy supply within the Armed Forces. Energy is supplied trough a logistic flow with processes such as production, storage, transportation and utilization. However, in research, energy systems are a domain of their own with a terminology that in many ways differ from practice within the logistic field. In order to find synergies between the fields, this report aims at investigating how logistic theory can be applied within the energy domain by describing the character of different energy systems. One of the challenges identified is that the supply of electricity and fuel in many cases are interchangeable and transform between one another. The report also provides an overview of the Swedish energy system and addresses opportunities for increased robustness through local networks. The goal for a future military energy system is described as a robust network, flexible in terms of energy carriers, well adapted to user requirements and with the ability to integrate between supply chains.