Since the introduction of energy harvesting and battery powered low- to mid-speed electronic circuits, supply voltages have been pushed to the physical limits of semiconductor devices for energy minimization and battery lifetime. Using the IBM 8RF-LM 0.13 ??m process and a modified library, an asynchronous ALU has shown to be capable of operating at 0.1 V. This paper presents the minimum energy analysis of a delay-insensitive asynchronous ALU, its modified version for minimum supply voltage operation, and the simulation results.