Exploring the economic benefits and stability of renewable energy microgrids with controllable power sources under carbon fee and random outage scenarios

This study investigates the application models and economic benefits of controllable power sources in microgrids under various carbon fee scenarios using a convenience store in Taiwan as a case study. Convenience stores are characterized by their high energy consumption and heavy reliance on stable power supply, and therefore underscore the importance of optimizing microgrid configurations to reduce operational costs and carbon emissions. This research adopts an innovative approach by integrating renewable-energy hybrid systems and advanced energy-storage technologies. Optimization simulations combining wind power, solar energy, and energy-storage systems are conducted using different HomerPro dispatch strategies, considering fixed parameters such as the nominal discount rate (2.125 %), inflation rate (1.37 %), and the annual average rate increase of Taiwan Power Company. These simulations evaluate their impact on system performance to enhance overall system efficiency and stability. During grid outages, self-generated renewable energy and storage systems may be insufficient to meet load demands, thus necessitating backup diesel generators. In this study, the formulated optimization problem explicitly aims to minimize the net present cost (NPC), which includes fuel costs, carbon emission fees, and capital investments, subject to feasible constraints such as power balance, battery state-of-charge (SoC) limits, and equipment capacity restrictions. Consequently, under these conditions, HomerPro’s simulation automatically dispatches the generator only when the available renewable energy generation and battery storage capacities are inadequate to supply the critical loads, thereby effectively minimizing overall operational costs and carbon emissions. The simulation result demonstrates that configuring generators for low-frequency use as backup power sources is an economically viable option. The innovation of this study lies in proposing a simulation framework that integrates renewable-energy hybrid systems and energy-storage technologies, enabling dynamic optimization analyses specifically for small businesses with critical power needs, such as convenience store. This framework not only addresses research gaps in this area but also provides practical insights to support businesses in achieving cost-efficiency and carbon-neutrality goals under carbon-fee pressures. • Carbon pricing shifts microgrid economics for convenience stores. • Simulated outages validate the resilience of hybrid microgrid configurations. • VRFBs boost carbon reduction in microgrids with high renewable energy adoption. • Li-ion batteries cut costs when renewable energy availability is moderate. • Backup generators support critical loads with minimal carbon and cost impacts.