There is more or less consensus around the problems related to the existing energy systems. Most focus has been on the negative environmental effects of using fossil fuels. Many papers and reports conclude that renewable energy has the potential to run the world and the technology needed to do so is available. An important question is: why such a big potential is only marginally utilized? This paper analyzes the reasons why we ended up in today's energy systems. In order to develop pathways for change, scenarios can be used to support decision making involving all key actors in the society. The scenarios must be established on the comparison between different primary energy sources at a fundamental thermodynamic level. The paper proposes the principles for evolutionary forecasting scenarios (EFS) with two sets of criteria to investigate technology development and long-term energy transition. Primary criteria are based on the first and second law of thermodynamics. They can-be used to simulate the development of energy transformation technologies. The result implies that engineers must consider the system level when they develop energy technology. The secondary criteria, which are mainly based on subjective-values, should be used for evaluating different roadmaps obtained from these simulations. It is important that the evaluations of scenarios are carried out in broad dialogue processes with key actors in order to make the roadmaps easy to implement and follow up in practice. (C) 2015 Elsevier Ltd. All rights reserved.