Goran Wall's "Exergy, Ecology and Democracy - Concepts of a vital society or a proposal for an exergy tax" has come a long way since its presentation in 1992. Wall has extended the thermodynamics to the sustainability analysis of economic, environmental and societal models. The authors of this paper aim to discuss Wall's intuitions in today's scenario. Governments are assuming increasing measures against climate change and toward sustainability. However, these measures do not affect the concentration of greenhouse gases and global heating. It is an evident failure from a thermodynamic point of view. The economic indicators used by governments to measure the progress toward U.N. Sustainability Development Goals and the Paris Agreement reveal a scarce consistency. One of the most used is "domestic material consumption" (DMC). It accounts for the mass balance of the materials entering or exiting a national economic system. However, it lacks consistency and delivers insufficient information because it neglects the impacts of import-export. As Wall shows, more effective and consistent indicators are necessary to account for sustainability. The most relevant is exergy, which has been presented and discussed widely.

Thirty years ago, Goran Wall published ?Exergy Ecology Democracy - Concepts of a vital society or a proposal for an exergy tax?. This paper discusses this milestone contribution by Wall. It has traced a path toward economic, environmental and societal sustainability and proposed exergy as a robust indicator for measuring progress. This paper is divided into two parts. The first focuses on better understanding Wall?s role in today?s scenario. This second part presents different methods that allow using exergy to assess the sustainability of economic, industrial and societal processes. First, it presents an example showing the inadequacy of domestic material consumption (DMC) in evaluating the sustainability of import-export operations. Second, how exergy can apply to increase the significance of DMC has been discussed. A new indicator that allows coupling with DMC has been defined to improve the information delivered by DMC and make it a more effective sustainability indicator. Third, some ecological indicators are discussed. The use of exergy to integrate DMC and assess lifecycle and polluting emissions into the environment has been discussed. Finally, an effective exergy tax proposal is presented as an instrument for stimulating an effective transition toward sustainability of consumption and people?s habits.