Water footprint approaches in Life Cycle Assessment : State-of-the-art and a case study of hydroelectric generation in the Høyanger area
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- Master's theses (INA) 
Life Cycle Assessment (LCA) currently fails to include impacts of freshwater use, and specification of water accounts in terms of geography and quality. Water footprints can be included in LCA to account and assess freshwater use, in combination with traditional methods such as Environmental Impact Assessment (EIA) and Risk Assessment (RI). A literature review is utilized to present the state-of-the-art for water footprint methods than can be combined with LCA. Based on identified methods, a theoretical framework for LCA of hydroelectric generation including water footprints is presented. Water footprint studies based on global averages have presented high water footprint values. The Høyanger hydropower scheme is used as a case study, assessing the change in water footprint values resulting from an impending upgrading and expansion of the power scheme in the area. This Master thesis calculate the water footprint of electricity produced in the Høyanger power scheme, using two methods. The first method (water footprinting according to Hoekstra) considers water losses through evaporation only. The second method (WF-3 developed by Herath and colleagues) accounts for both water inputs through precipitation and water losses through evaporation. Both methods produced significantly lower results than what have been presented in other water footprint studies of hydroelectric generation, with global average values of 68 and 22 m3/GJ. Employing the first method, weighted average water footprints decreased in value from 1.21 to 1.05 m3/GJ, indicating benign impacts of freshwater use changes as a result of the upgrading and expansion. The second method produced negative values for all studied power plants, indicating that the Høyanger region collects more precipitation than it loses through evaporation. Accounting for water inputs in addition to water outputs provides information of the water stress in the region. To add such information to the water footprints produced utilizing the first method, these were characterized according to a stress water index provided by Pfister and colleagues. The characterized values decreased from 0.013 to 0.012 m3/GJ. LCA can provide accounts for potential impacts of freshwater use. For complete qualitative environmental assessment, LCA should be used in a combination with EIA and RI. The EIA for the upgrading and expansion project was reviewed to add qualitative environmental information to the analysis.