Abstract: A method for heat integration between a chemical synthesis plant that runs an exothermic reaction and (ii) and a partner plant that generates a working fluid such as steam (e.g., runs a power cycle). The present disclosure describes both internal and external heat integration. Internal heat integration may provide heat from the exothermic reaction (e.g., from methanol synthesis) to a reboiler associated with a distillation column of the chemical synthesis plant. External heat integration may use heat from the exothermic reaction to preheat a condensed water stream (which stream is downstream from the turbine and condenser of the power cycle). Such reduces the need for bleed off the turbine to preheat condensed water as part of the power cycle. A bleed off the turbine provides heat to the reboiler associated with the distillation column of the chemical synthesis plant. Heat integration provides overall improved energy use within both plants.