Capturing CO2 and storing it underground has been proposed to be a major player in mitigating global climate change by reducing CO2 emission. Thermal power plants, being the largest point source of CO2 emission, naturally become the primary target of CO2 capture and storage (CCS). However, it is often overlooked that power plant is not only the largest CO2 emitter, but also the largest fresh water consumer. This study, conducted by researchers in the Department of Engineering and Public Policy of Carnegie Mellon University, presents a thorough analysis on the additional water demand imposed by CCS in power plants, and provides guidance to address this issue. Working at the water-energy nexus, we need a broader vision to solve the emerging challenges.