The availability of molecular resources is of paramount importance in molecular communication (MC), where information is intricately encoded within the properties of molecules. In MC, the acquisition of molecules from the environmental mixture is followed by the essential process of purifying these molecules through controlled transfers between reservoirs, especially for molecular shift keying (MoSK). This paper focuses on a transmitter featuring dual reservoirs designated for the storage of information molecules, with the transference of a specific molecular species from one reservoir to another facilitated by the consumption of free energy. Given the constrained energy resources within the transmitter, we investigate an energy-efficient mechanism for transmitter creation, aimed at optimizing overall transmitter performance. Theoretical analyses are systematically conducted to explore diverse strategies for the movement of molecules between reservoirs. Ultimately, numerical results substantiate the efficacy of the proposed molecular movement strategy in the transmitter creation.