A methodology to estimate the unit exergy cost of water supply alternatives is provided.
Two alternatives (water transfers and groundwaters) are defined.
The unit exergy costs are given as a function of design and operating parameters.
Unit exergy cost of groundwaters go from 1.01 to 2.67 and from 1 to 4.06 in water transfers.
Unit exergy costs are calculated and contrasted for the medium course of the Ebro.