A stand-alone hybrid renewable energy system assessment using cost optimization method

In this paper, a stand-alone hybrid renewable energy system is proposed, which consists of solar PV, wind turbine, and energy storage with the combination of battery and hydrogen. This energy storage system partly relies on energy conversion through two components, electrolysis and fuel cell. When the hybrid system generates more electricity than load demand, hydrogen is produced via electrolysis and stored in a tank; when the hybrid system needs more electricity, the fuel cell can convert hydrogen back into electricity. Cost optimization of the proposed hybrid system is essential for finding optimal sizing of individual components. In this paper, the net present cost (NPC) method is used to minimize the total cost of the system through the software tool HOMER (Hybrid Optimization Model for Electric Renewables) developed by National Renewable Energy Laboratory. The NPC method is best tailored for such a purpose because it considers all revenues and costs occurring during the life cycle of the project. A case study is conducted for economic assessment of the proposed hybrid system implemented in Ardabil, north-western Iran. Two additional energy storage scenarios, with only battery and with only hydrogen, are also investigated in the case study. It is found that using the combination of battery and hydrogen as energy storage is a more efficient option. The proposed stand-alone hybrid renewable energy system is suitable to supply power for rural homes and farms, and marine electric systems.