A national-level LCA of a water supply system in a Mediterranean semi-arid climate—Israel as a case study

Purpose: Our aim is to assess the environmental impacts associated with the provision of tap water in Israel and adjacent regions. The main objective of this paper is to present the life cycle assessment (LCA) of the Israeli water supply system in order to evaluate and understand the sources of the largest impacts in the system and derive conclusions related to countries and regions with similar climate using similar water production technologies. Methods: We defined the functional unit of our study to be 1 m³ of potable water distributed to the point-of-use. Our scope includes sub-systems’ operation and infrastructure construction and decommissioning. An LCI dataset of tap water was generated, and an LCA that covers the value chain of the country’s complex water supply system was conducted. The Israeli water supply system includes water abstraction and production from groundwater, surface water, brackish water, and seawater; water treatment; desalination; a national transmission system, which runs throughout the country; and distribution to the final consumer. The study comprises data collection for all components of the Israeli water system, resulting in the first national-level LCA of tap water. The life cycle inventory data comprises energy and chemical consumption, materials for infrastructure, and materials’ transportation. Results and discussion: The processes with the main impacts in most of the environmental categories are the reverse-osmosis desalination of seawater and the long and energy-intensive transmission and distribution system. However, by changing the electricity mix to a cleaner one, the impacts of the water supply system are reduced even more than by reducing the share of desalination. In two impact categories (terrestrial ecotoxicity and mineral resource scarcity), the infrastructure is the major contributor to the total impact. Leakage of water throughout the system also has considerable impacts. As expected, freshwater use decreases with the increase of desalination, which uses seawater rather than depleting freshwater. Conclusions: This LCA represents a region with limited freshwater supply that is dependent on desalination. Israel and adjoining regions in Golan and the West Bank are similar to an increasing number of regions and can be used as a proxy for tap water production in LCAs of products from these regions. High consumption of electricity for desalination is an important cause of the large impact scores of the Israeli water supply system. The high scores are due to using only a small fraction of clean primary fuels in the electricity grid.