A power generation system comprising: a first heating fluid circuit thermally coupled to a first plurality of heat sources (102a-102g) from a first plurality of sub-units of a petrochemical refining system, the first plurality of sub-units comprising a para-xylene separation unit and an atmospheric distillation-Naphtha hydrotreating-aromatics plant; a second heating fluid circuit thermally coupled to a second plurality of heat sources (103a-103c) from a second plurality of sub-units of the petrochemical refining system, the second plurality of sub-units comprising an aromatics refining system; a third heating fluid circuit thermally coupled to a third plurality of heat sources (105a-105j) of a third plurality of sub-units of the petrochemical refining system, the third plurality of sub-units comprising a hydrocracking-diesel hydrotreating system; a first power generation system that comprises a first organic Rankine cycle, the first organic Rankine cycle comprising i) a first working fluid that is thermally coupled to the first and second heating fluid circuits (102, 103) to heat the first working fluid, and ii) a first expander configured to generate electrical power from the heated first working fluid; a second power generation system that comprises a second organic Rankine cycle, the second organic Rankine cycle comprising i) a second working fluid that is thermally coupled to the second heating fluid circuit to heat the second working fluid, and ii) a second expander configured to generate electrical power from the heated second working fluid; and a control system configured to actuate a first set of control valves to selectively thermally couple the first heating fluid circuit to at least a portion of the first plurality of heat sources (102a-102g), the control system also configured to actuate a second set of control valves to selectively thermally couple the second heating fluid circuit to at least a portion of the second plurality of heat sources (103a-103c), the control system also configured to actuate a third set of control valves to selectively thermally couple the third heating fluid circuit to at least a portion of the third plurality of heat sources (105a-105j). a first heating fluid circuit thermally coupled to a first plurality of heat sources (102a-102g) from a first plurality of sub-units of a petrochemical refining system, the first plurality of sub-units comprising a para-xylene separation unit and an atmospheric distillation-Naphtha hydrotreating-aromatics plant; a second heating fluid circuit thermally coupled to a second plurality of heat sources (103a-103c) from a second plurality of sub-units of the petrochemical refining system, the second plurality of sub-units comprising an aromatics refining system; a third heating fluid circuit thermally coupled to a third plurality of heat sources (105a-105j) of a third plurality of sub-units of the petrochemical refining system, the third plurality of sub-units comprising a hydrocracking-diesel hydrotreating system; a first power generation system that comprises a first organic Rankine cycle, the first organic Rankine cycle comprising i) a first working fluid that is thermally coupled to the first and second heating fluid circuits (102, 103) to heat the first working fluid, and ii) a first expander configured to generate electrical power from the heated first working fluid; a second power generation system that comprises a second organic Rankine cycle, the second organic Rankine cycle comprising i) a second working fluid that is thermally coupled to the second heating fluid circuit to heat the second working fluid, and ii) a second expander configured to generate electrical power from the heated second working fluid; and a control system configured to actuate a first set of control valves to selectively thermally couple the first heating fluid circuit to at least a portion of the first plurality of heat sources (102a-102g), the control system also configured to actuate a second set of control valves to selectively thermally couple the second heating fluid circuit to at least a portion of the second plurality of heat sources (103a-103c), the control system also configured to actuate a third set of control valves to selectively thermally couple the third heating fluid circuit to at least a portion of the third plurality of heat sources (105a-105j).