Flowing a first buffer fluid and a second buffer fluid through a heat exchanger network thermally coupled to heat sources of a Natural Gas Liquid (NGL) fractionation plant, and transferring heat from the heat sources to the first buffer fluid and the second buffer fluid. Generating power via a first sub-system thermally coupled to the heat exchanger network and generating potable water from brackish water via a second sub-system thermally coupled to the heat exchanger network.