A power generation system comprising: a first heating fluid circuit thermally coupled to a plurality of heat sources (103a, 103b)from a plurality of sub-units of a petrochemical refining system; a second heating fluid circuit thermally coupled to the plurality of heat sources (103a, 103b) from the plurality of sub-units of the petrochemical refining system; a third heating fluid circuit thermally coupled to the plurality of sources (105a-g) from the plurality of sub-units of the petrochemical refining system; a fourth heating fluid circuit thermally coupled to the plurality of sources (107a-c) from the plurality of sub-units of the petrochemical refining system, wherein the plurality of sub-units comprises a hydrocracking plant, an aromatics plant, and a diesel hydro-treating plant, wherein a first subset of the plurality of heat sources comprises a plurality of aromatics plant heat exchangers coupled to streams in the aromatics plant, wherein a second subset of the plurality of heat sources comprises a plurality of hydrocracking plant heat exchangers coupled to streams in the hydrocracking plant, and wherein a third subset of the plurality of heat sources comprises a plurality of diesel hydro-treating plant heat exchangers coupled to streams in the diesel hydro-treating plant; a first power generation system, a second power generation system, and a third power generation system comprising a first organic Rankine cycle, a second organic Rankine cycle and a third organic Rankine cycle, respectively, the first organic Rankine cycle comprising i) a first working fluid that is thermally coupled to the first heating fluid circuit and the second heating fluid circuit to heat the first working fluid, and ii) a first expander configured to generate electrical power from the heated first working fluid, the second organic Rankine cycle comprising i) a second working fluid that is thermally coupled to the third 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 the third organic Rankine cycle comprising i) a third working fluid that is thermally coupled to the fourth heating fluid circuit, and ii) a third expander configured to generate electrical power from the heated third working fluid; and a control system configured to activate a set of control valves to selectively thermally couple each of the first heating fluid circuit, the second heating fluid circuit, the third heating fluid circuit and the fourth heating fluid circuit to at least a portion of the plurality of heat sources. a first heating fluid circuit thermally coupled to a plurality of heat sources (103a, 103b)from a plurality of sub-units of a petrochemical refining system; a second heating fluid circuit thermally coupled to the plurality of heat sources (103a, 103b) from the plurality of sub-units of the petrochemical refining system; a third heating fluid circuit thermally coupled to the plurality of sources (105a-g) from the plurality of sub-units of the petrochemical refining system; a fourth heating fluid circuit thermally coupled to the plurality of sources (107a-c) from the plurality of sub-units of the petrochemical refining system, wherein the plurality of sub-units comprises a hydrocracking plant, an aromatics plant, and a diesel hydro-treating plant, wherein a first subset of the plurality of heat sources comprises a plurality of aromatics plant heat exchangers coupled to streams in the aromatics plant, wherein a second subset of the plurality of heat sources comprises a plurality of hydrocracking plant heat exchangers coupled to streams in the hydrocracking plant, and wherein a third subset of the plurality of heat sources comprises a plurality of diesel hydro-treating plant heat exchangers coupled to streams in the diesel hydro-treating plant; a first power generation system, a second power generation system, and a third power generation system comprising a first organic Rankine cycle, a second organic Rankine cycle and a third organic Rankine cycle, respectively, the first organic Rankine cycle comprising i) a first working fluid that is thermally coupled to the first heating fluid circuit and the second heating fluid circuit to heat the first working fluid, and ii) a first expander configured to generate electrical power from the heated first working fluid, the second organic Rankine cycle comprising i) a second working fluid that is thermally coupled to the third 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 the third organic Rankine cycle comprising i) a third working fluid that is thermally coupled to the fourth heating fluid circuit, and ii) a third expander configured to generate electrical power from the heated third working fluid; and a control system configured to activate a set of control valves to selectively thermally couple each of the first heating fluid circuit, the second heating fluid circuit, the third heating fluid circuit and the fourth heating fluid circuit to at least a portion of the plurality of heat sources.