Exergy and UN Sustainable Development Goals

Current economic models and indicators need to be rethought and redesigned to create a more sustainable society. Exergy could be introduced as an objective measure of sustainability and an exergy tax can be levied to encourage environmentally friendly behaviour. A closer link between thermodynamic principles and economic analyses can support sustainable development.

In a study, Trancossi et al. analyse the potential of exergy for a sustainable economy, in particular the link between exergy and the UN Sustainable Development Goals (SDGs). The authors emphasise that the SDGs and the Paris Agreement are necessary processes to promote sustainability. However, the current measures are not sufficient to mitigate the threats posed by climate change. The authors criticise current indicators such as Domestic Material Consumption (DMC) as insufficient for assessing the sustainability of import-export operations and suggest using exergy to increase the importance of DMC and create a more accurate sustainability indicator.

Exergy is emphasised as a benchmark because an exergy analysis can analyse social flows and processes (such as energy conversion systems, industrial plants and transport systems) using the second law of thermodynamics. This type of analysis can better reflect environmental impacts and resource utilisation than a pure mass balance. In addition, material flow analysis (MFA) is used as a tool for the systematic evaluation of material flows and stocks in social processes. This method helps to improve environmental impact and resource efficiency.

Another concept is cumulative exergy consumption (CExC), which describes how a process reduces the quality of available resources. CExC includes the exergy required to assess the quality of energy and materials. Exergy can also be considered as an economic value used in exergy economic methods to optimise the financial use of resources. It is proposed to introduce an exergy tax to promote sustainability and regulate economic activities.

Case studies are also presented to illustrate the theoretical concepts. A good example is the production and transport of PET bottles, where various production and transport scenarios were analysed. The study shows that transport routes have a significant impact on exergy loss and environmental impact. Another case study analysed the efficiency of different heating technologies (conventional heating systems vs. induction heating) in food production. This showed that induction heating is more efficient and causes less exergy loss.