How to measure and optimize the sustainability of complex (renewable) energy production pathways:: applied to farm scale biogas production pathways

To avoid energy scarcity as well as climate change, a transition towards a sustainable society must be initiated. Within this context, governmental bodies and/or companies often note sustainability as an end goal, for instance as a green circular economy. However, if sustainability cannot be clearly defined as an end goal or measured uniformly and transparently, then the direction and progress towards this goal can only be roughly followed. A clear understanding of and a transparent, uniform measuring technique for sustainability are hence required for sustainable and circular (renewable) energy production pathways (REPPs), as society is asking for an integrated and understandable overview of the decision-making and planning process towards a future sustainable energy system. Therefore, within this dissertation, a new approach is proposed for measuring and optimizing the sustainability of REPPs; it is useful for the analysis, comparison, and optimization of REPP systems on all elements of sustainability. The new approach is applied and tested on a case based on farm-scale, anaerobic digestion (AD), biogas production pathways