Modelling and Optimization of Stand-alone Pv-diesel Hybrid System with Hydrogen Storage: Case of Algeria

Abstract

"Renewable energy-based off-grid systems have been considerably growing in popularity in last few years. This kind of systems is referred to as decentralized electricity supply system that can provide power to meet the needs of individual households or small communities in rural populations, mainly in regions where the national grid is not economical to be extended due to the remoteness of the region. A hybrid system comprises one or several renewable energy technologies as primary energy sources and a conventional fossil fuelled-based technology. Therefore, several system configurations can be used to meet the need of the power load. The aim of this study is to find the optimum system configuration of a hybrid power system that can supply electricity to a rural community in south of Algeria. A rural village from the region of Adrar containing 15 households is selected with a daily electricity demand of 145.44 kWh and a day-time peak of 39.80 kW. In addition, the optimum hybrid power system can also produce hydrogen using the electrolysis of water process. The region of Adrar receives abundant solar radiation with an annual average of 6.26 kWh/m2/day. Therefore, solar PV technology is the only used renewable energy generation system. In this study, HOMER Pro. (Hybrid Optimization Model for Electrical Renewables) computer modeling software was used to model the power system, its physical behavior and its life cycle cost. Sensitivity analysis with minimum renewable fraction and solar radiation variations was also done. It has been found that the combination of PV system, three diesel generators, an electrolyzer and a hydrogen tank yields the optimum hybrid system type. The hybrid system configuration has been found to be 21.7kW-PV, three 10kW-diesel genset, 20.0kW-electrolyzer and 380kg-hydrogen tank. The PV system generates 51.24% of the total system energy generation. The remaining 48.76% is generated by the diesel generators resulting a total hours of operation of 7,044 hrs/yr. The total Net Present Cost NPC of this hybrid power system was found to equal $823.744 and electricity can be supplied at an approximate cost of energy LCOE of 0.60 $/kWh despite the variation in the annual average solar radiation in the range of 4.10-6.26 kWh/m2/day. However, with an increase in the minimum renewable fraction to 40%, both the NPC and the LCOE would increase significantly. Moreover, the hydrogen gas that can be generated using electrolysis of water was found to be 353 kg/yr with an energy capacity of approximately 11,750 kWh."