All’interno di un piano che punti a migliorare le prestazioni energetiche di un’attività, non è necessario solamente sapere quanto si consuma come valore assoluto: questi dati, infatti, devono essere inquadrati all’interno di un’analisi che faccia capire se si tratta di numeri soddisfacenti, oppure se la propria azienda è inefficiente. Per fare questo secondo importante passo è necessario identificare particolari indicatori, detti Energy Performance Indicator, o EnPI: in estrema sintesi, si tratta di strumenti in grado di monitorare le prestazioni energetiche. Rispetto al concetto di efficienza, che misura la produzione per unità di energia, qui si passa al concetto di intensità energetica, ossia la quantità di energia utilizzata per unità di prodotto. The goal is to increase efficiency or decrease intensity.
In a Energy Management System (SGE) which provides for the continuous improvement of energy performance on a constant basisEnergy Performance Indicators are the basis to proceed to the “check” phase of the virtuous circle structured in the four steps of the Deming cycle:
After planning the initial activities to improve performance and after implementing them, it is the moment when the effort made occurs and further improvement actions are subsequently implemented. The international standard ISO 50001 issued in 2011, which certifies energy management systems, introduces the concept of EnPI as an important novelty, with the aim of adopting a tool for comparing energy performance over time.
An EnPI system basically allows to obtain:
- a quantitative performance measurement system;
- a tool for knowing progress;
- an anomaly identification system.
The preparation of EnPI will make it possible to relate the various activities to understand which are the most energy-intensive, to make monthly or annual comparisons to see the effects of the interventions carried out and to make a comparison with the benchmarks relating to their sector of activity. Furthermore, it allows you to predict, based on historical data, the expected consumption as the production changes.
Knowing how to analyze the production process
Once the company’s initial energy situation has been clarified (the so-called “baseline” of consumption detected at a given time), to proceed with efficiency measuresit is necessary to prepare the Energy Performance Indicators. This is a task that varies greatly depending on the situation, and is often complicated, especially in the case of companies distributed across the territory with multiple locations and production plants and with the use of multiple energy sources.
The definition of the energy performance indices implies that you know your company’s activity very well, the most energy-consuming production processes and all the other activities that need energy (thermal or electric) to be carried out. The most relevant users must be highlighted because it will probably be from these that the most significant performance improvements can be obtained. Per ciascuna utenza energetica significativa si predisporrà quindi an indicator that relates consumption to the variable that most influences it.
For example, depending on the sector of activity, it may be the consumption of gas per unit of product, or the consumption of kWh per square meter of illuminated surface or, again, the consumption of light or gas per bed. The definition of EnPI involves a real consumption monitoring architecture, and often involves ad hoc measurements and the installation of new measuring instruments.
The development of the EnPI involves these steps:
- determine the elements / assets to be assessed (plants, processes, systems, etc.);
- determine the relevant energy consumption for each element;
- identify the different drivers that influence consumption (the production volume, but also factors such as the weather or the number of people in a building);
- collect historical and driver consumption data;
- establish a “baseline”, ie a zero year on which to make subsequent comparisons;
- analyze the links between consumption and drivers;
- analyze the change over time of the indicator compared to year zero.
Once the photograph of the performance of energy performance over time has been obtained, and the comparison with the reference benchmarks has been carried out, the energy manager remains responsible for inserting these results in a report and communicating them effectively within the organization, before proposing improvements.