Perspectives for alternative energy carriers based on renewables from technical and energetic point-of-view

Alternative energy carriers (AEC), based on renewable CO2-poor or CO2-free sources of energy, are of central importance for the transition towards a sustainable energy system. The most important AEC currently discussed are: hydrogen and electricity from renewable energy sources and other AEC based on biomass. The core objective of this paper is to provide an appraisal of the prospects of these AEC up to 2050 from a technical and energetic point-of-view. The major conclusion is that there is no single "one size fits all" energy carrier which can be considered to serve all problems alone. All AEC analyzed in this paper still face major problems in different parts of the overall energy service providing chain.