Water plays a key role for the national energy system, both directly in hydroelectric plants and indirectly within other components of the system that use water in one or more phases of the production cycle (cooling, biomass cultivation, carbon capture and storage – CCS). At the same time, water is fundamental for civil, agricultural, public, and industrial uses, which often gives rise to conflicts that need to be resolved through priority management.
Although the quality of information on water availability and demand in the national territory is still rather poor, the need for an overall vision of the qualitative-quantitative interactions between the water and energy systems has taken on ever greater importance in recent years, prompting a series of international studies on the so-called “Water-Energy Nexus” (WEN).
The general objective of this line of research is to provide a contribution to improving the sustainability of the energy system, thanks to a better knowledge of the relationships between water and energy.
The analysis of water-energy interactions has led to the definition of a methodology which allows the evaluation of annual water and energy flows by integrating the data available from different databases with estimated data.
The results of the methodology are displayed through a schematic representation (i.e., the Sankey diagram) of water-energy flows on a national scale, highlighting both the supply (water resources) and production/import (energy resources) phases, as well as the consumption for the different uses of resources.
The results obtained show, in particular, the evolution of the water-energy connection (water flows as input to the energy system and energy flows as input to the water system) from the current state (years 2016-2019) to the 2030 and 2050 scenarios identified from current plans for the energy transition.
The theme of water-energy interaction and its evolution is particularly evident in hydroelectric plants for which the study was conducted with a different approach, given the specific features of this energy source. In particular, a statistical model was developed to predict the monthly hydroelectric energy producibility for each electricity market area based on the water resource availability scenarios resulting from expected climate changes.