A confusion of tongues or the art of aggregating indicators--Reflections on four projective methodologies on sustainability measurement

To achieve consensus on the broad term sustainability abstractness is required. In turn, to take sustainability as an action guiding mandate for implementation it needs to be concrete. The paper seeks to bridge the gap from theory of sustainability to practical application by implementing four different methods, i.e. social cost analysis, ecological footprint analysis, exergy approach and multi criteria decision analysis (MCDA). These methods will be exemplarily applied for sustainability analysis of household heating technologies focusing on wood pellet boilers, wood chip fired district heating stations and natural gas fired condensing boilers. Based on the integrated assessment of exemplary heat supply technologies a critical outlook on the four projective approaches is given.