“…Efforts have differed both in scope (e.g., electricity generation—Macknick, Newmark, et al, 2012; Peer & Sanders, 2016, 2018; Pfister et al, 2011; single fuel cycles—Klise et al, 2013; Nicot & Scanlon, 2012; Scanlon et al, 2014; Wu et al, 2014; or snapshots of energy systems—Gleick, 1994; Grubert & Sanders, 2018) and in categorization, with particular differences observed in the way that characterization studies have dealt with the fact that “water” is not fully descriptive of the resource in question (Boulay et al, 2011; Grubert et al, 2020). For example, choices to evaluate only freshwater (Raptis et al, 2020) versus multiple water qualities (Grubert & Sanders, 2018), and how those choices are described and justified, vary by study. One proposal for water categorization includes 17 separate categories (Boulay et al, 2011): high resolution is desirable but can be evasive in practice given water data quality constraints (Grubert et al, 2020; Perrone et al, 2015).…”