This paper presents a synthesis method for interplant heat integration where the participating plants have multiple periods of operations with unequal durations. The method adopted is the energy hub approach where interplant heat integration and heat exchange with hot and cold utilities occur at the energy hub while intra-plant heat integration occurs at the individual plant level. The example considered involves three plants that are co-located with each plant having a 2-period operational profile involving daytime and night-time. The multiperiod profile for plant 1 spans 12 hours for the daytime period and 12 hours for the night-time period. That of plant 2 spans 10 hours for the daytime and 14 hours for the night-time while that of plant 3 spans 8 hours for the daytime and 16 hours for the night-time. The unequal periodic durations across the three plants were synchronised using a newly developed operational period mapping approach that gave rise to 4 periods for the interplant heat integration. The solution obtained from the example considered involves 14 heat exchangers of which 6 are intra-plant heat exchangers, 5 are utility exchangers while 3 are interplant process heat exchanger at the energy hub.