Islanded power systems are generally exposed to higher expenses and more grid stability challenges compared to larger interconnected power grids. The interconnection of islanded power systems can lead to numerous advantages. In this work, the techno-economic modeling of the interconnection of two remote communities is presented to ex- plore the feasibility and the economic advantages of an electrical intertie, as well as the challenges from a technical perspective. The unique case study explores two different intertie voltage levels for an AC and a DC intertie. Instal- lation cost estimates were obtained for each intertie case as well as the necessary upgrade costs to keep the system unconnected. These scenarios were simulated using HOMER Pro energy balance models of the system with and without energy storage. The study considers the voltage drop and the power loss along the 25-mile intertie for the power balance modeling process. It is found that with available cost estimates the MVDC intertie economically out- performs the MVAC intertie as well as the current standalone configuration of the modeled islanded power systems. The MVDC intertie scenario outperforms the standalone configuration even with the inclusion of the energy storage required to increase the reliability of the intertied scenarios.

This research was funded by the Department of Energy (DOE) Office of Electricity (OE) Energy Storage Program, through Sandia National Laboratories. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy's National Nuclear Security Administration under contract DE- NA0003525. The authors gratefully acknowledge Dr. Imre Gyuk, program manager for the DOE OE Energy Storage Program, for his support of this work.