Technical and economic assessment of grid-independent hybrid photovoltaic-diesel-battery power systems for commercial loads in desert environments

Solar photovoltaic (PV) hybrid system technology is a hot topic for R&D since it promises lot of challenges and opportunities for developed and developing countries. The Kingdom of Saudi Arabia (KSA) being endowed with fairly high degree of solar radiation is a potential candidate for deployment of PV systems for power generation. Literature indicates that commercial/residential buildings in KSA consume an estimated 10-45% of the total electric energy generated. In the present study, solar radiation data of Dhahran (East-Coast, KSA) have been analyzed to assess the techno-economic viability of utilizing hybrid PV-diesel-battery power systems to meet the load requirements of a typical commercial building (with annual electrical energy demand of 620,000Â kWÂ h). The monthly average daily solar global radiation ranges from 3.61 to 7.96Â kWÂ h/m2. NREL's HOMER software has been used to carry out the techno-economic viability. The simulation results indicate that for a hybrid system comprising of 80Â kWp PV system together with 175Â kW diesel system and a battery storage of 3Â h of autonomy (equivalent to 3Â h of average load), the PV penetration is 26%. The cost of generating energy (COE, US$/kWÂ h) from the above hybrid system has been found to be 0.149Â $/kWÂ h (assuming diesel fuel price of 0.1Â $/L). The study exhibits that for a given hybrid configuration, the operational hours of diesel generators decrease with increase in PV capacity. The investigation also examines the effect of PV/battery penetration on COE, operational hours of diesel gensets for a given hybrid system. Emphasis has also been placed on unmet load, excess electricity generation, percentage fuel savings and reduction in carbon emissions (for different scenarios such as PV-diesel without storage, PV-diesel with storage, as compared to diesel-only situation), cost of PV-diesel-battery systems, COE of different hybrid systems, etc.Solar radiation PV modules Battery Diesel generators Commercial loads Carbon emissions