Water resources play a fundamental role in the national energy system, both directly in hydroelectric plants and indirectly in 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 essential for civil, agricultural, public, and industrial uses, and this multiple-use often leads to conflicts that must be resolved by prioritizing management. Despite the limited quality of information on water availability and demand at the national level, the need for an integrated view of the qualitative and quantitative interactions between the water and energy systems has gained increasing importance in recent years, leading to a series of international studies on the so-called Water-Energy Nexus (WEN).

In this study, a data model was developed to outline water-energy flow interactions on a national scale, starting with a review of available data and defining methodologies to estimate missing data. The estimated data were used to create a preliminary schematic representation of water-energy flows on a national level, highlighting both the supply phases (water resources) and production/import (energy resources), as well as consumption for various uses. The resulting scheme provides a first snapshot, relative to the reference year 2016, of the water-energy nexus within the Italian context.