A waste heat recovery system includes a high pressure turbine and a low pressure turbine, in which the high pressure turbine receives high pressure working fluid vapor, the low pressure turbine receives low pressure working fluid vapor and the high pressure turbine also supplies low pressure working fluid vapor to the low pressure turbine. A recuperator receives working fluid vapor from the low pressure turbine. The recuperator produces heated condensate, at least a portion of which is provided to a high pressure vaporizer. The high pressure vaporizer is configured to receive from a high temperature heat source and produces high pressure working vapor used to power the high pressure turbine. The remaining condensed fluid is provided to a low pressure vaporizer which is configured to receive heat from a low-temperature heat source, thereby producing low pressure working fluid vapor used to power the low pressure turbine.