. c, Tradeoff relationship between embodied water consumption and CO2-eq emission by different power sources, including electricity grids in different locations (⊙), purely power sources (⊡), and Nevada renewable energy tariff (NV*, ◬). The red dashed line denotes the lower bound of the water-CO2 performance, i.e., the existing electricity grids that have the lowest water consumption and CO2-eq emission simultaneously, and the green shaded area covers the power sources that can transcend the current limit of water-CO2 performance.