Integrating renewable energy generators with existing electric power systems is essential in developing renewable energy generation in electric power systems in islands and remote areas. The high penetration of renewable energy sources (RES) and the possibility of working in a connected mode with the existing electricity grid are significant problems that must be overcome. With the many RES implementations, a proper integration method is needed between RES plants, which have intermittent characteristics, and existing power generation systems so that the electrical system remains stable, continuous, and reliable. One of the power plant integration schemes is unit commitment (UC), a daily scheduling method to achieve optimization goals while still meeting various operational, environmental, and technical constraints. UC method development is needed to maintain system stability, resilience, and minimize operating costs, especially for small systems for electrical development. Therefore, it is necessary to develop a new optimization method in the UC scheme for microgrid power systems. This paper discusses the development of an optimization method to integrate power generation from intermittent renewable energy using a UC scheme in a microgrid system. The algorithm used is a combination of improved priority list techniques and genetic algorithms, where the improved priority list is run first for scheduling optimization and then a combination of the algorithm priority list and genetic algorithm for economic dispatch solutions to obtain the lowest operational costs. The generating unit's capacity to operate per capability segment is also taken into account in the operation scheduling and affects the number of iterations in the genetic algorithm's operation. This method has been simulated in the electrical system in Eastern Indonesia, which is a developing power system and has an intermittent characteristic of RES power plants.