Sustainability Assessment of Technical Efficiency Measures: the Terpsichore Method

Since 2022, sustainability has taken on a new technical, economic, and social relevance given the challenges introduced by the Sustainable Development Goals, the COVID-19 pandemic, and the war on the energy sector. A huge and still growing number of sustainability evaluation models and frameworks have been developed to support conscious environmental decision-making. However, these models are quite complex and with limited applicability to real contexts, especially for small and medium enterprises. This study proposes a method for evaluating the overall benefits deriving from the energy transitions resulting from technical efficiency measures considering environmental (global and local), energy, economic, and socio-economic performance. The benefits can be evaluated with exclusively technical or integrated criteria considering the strategic directions of the administration, the territory, or the industry. Benefits are assessed collectively periodically, typically by year and by unit of service/good. The evaluations of the benefits can be referred to the investment unit to establish an objective order of priority in the strategic directions and the financings. To carry out these evaluations, a coherent set of definitions and procedures supported by a set of coherent synthesis graphic representations was introduced, which takes the name of the "Terpsichore Method". Finally, two examples of the application of the method are reported to assess the benefits derived from i) the installation of a photovoltaic system on the available surface of the roof in a typical winery and ii) the use of wasted thermal energy from a steel mill to power a district heating network.