Recently, studies have focused on the development of an energy management system (EMS) with renewable energies obtained from various sources such as sunlight, wind, and rain to build a low-carbon society. EMS simulation plays an important role in the development of the system because the renewable energies are unstable and depend on the environment. This paper investigated modeling and simulation techniques of the EMSs. Specifically, the study examined an electrical circuit simulation program, SPICE (simulation program with integrated circuit emphasis). SPICE was used to model and simulate a home energy management system (HEMS) and an autonomous micro-grid system. The findings verified that SPICE was effective in both the EMS analysis as well as the electric circuit analysis.