In various embodiments, a system and method are provided for storing a liquid mixed refrigerant (MR) separated and stored as Low boiling point (LBP) and high boiling point (HBP) components. These storage components are later used in conjunction with heating and/or cooling sources in effecting the operation of a Rankine cycle to generate electric or mechanical power on a dispatch or when needed basis. The MR is reconstituted by combining the LBP and HBP. In a cycle, the LBP and HBP are later separated from the MR utilizing sporadically available energy sources (for example, solar, wind, hydro, etc.) or consistently available sources (for example geothermal).