Abstract for: Ex Ante and Ex Post Sustainability of Energy Choices
The challenge of sustainability has reached everybody. The concept is mostly used as a normative concept but has too many interpretations. System dynamics provides a reasonable method to avoid the intragenerational and intergenerational subjectivity of this term. The formal approach reveals not only the boundaries and the causal structure of the examined system but although the hidden presuppositions of the modeler. “Ex ante” sustainability will be ensured by the modeling procedure, since sustainability means that the chosen variables in the system with a particular model-structure are in the preferred range in the specific period of time. “Ex post” sustainability, as the judgment of “next generations”, can be reached only if the model includes the changing preferences of future observers. The problem of ex ante and ex post sustainability will be demonstrated with a model of the energy system in a “small world”. The decision-makers face the situation how to allocate the finite fossil energy reserve between energy efficiency retrofit of buildings and development of renewable energy potential. This is a realistic dilemma because they have to satisfy although the operating energy demand of the world and they do not know how much fossil energy is still available.