Design And Evaluation Of A Grid Connected Photo Voltaic (Pv) System: A Case Study Of Moi University Administration Block

Abstract

Moi University relies on utility grid whose major sources are centralized generation with petroleum, hydro and geothermal resources. With increasing students enrolment every year, the grid power is not adequate, hence frequent outages are experienced. During the occurrence, diesel generators are utilized as backup. However, fuel is expensive for its operation. Fortunately, Moi University administration block is at geographical location of 0.286°N latitude and 35.294°E longitude, where availability of solar resource is throughout the year. The average has been indicated to be 5.56 kWh/m 2 /day. Therefore, the main aim of this research was to design, simulate and evaluate a grid-connected system for Moi University administration block. The specific objectives were: to evaluate the optimal values of solar resource parameters with respect to tilt and orientation; to map and collect power rating data of power consumer in the administration block; to design and simulate a grid connected PV system based on the outcome of first and second objectives and finally to evaluate the economic impact of incorporating battery bank to the grid connected system. To design an ideal grid connected PV system this study had to get ideal solar resource parameters through experimentation by varying solar panel tilt and orientation. Administration block’s power demand was obtained through physical load audit and utility company bills (KPLC bills) to obtain load demand as well as identifying the amount critical load power consumption. Lastly, a grid connected system was designed, simulated at this ideal orientation and its performance evaluated by PVsyst software. The economical evaluation was done with respect to current market prices. The orientation of the building was found to be desirable for having most of its roof surface area on its longitudinal length sloping downward midway along North and South axis to forming solar plane Azimuth 159 ° and −21 ° . The obtained load was 19745 kWh per Month, with 66.24 kWh being daily critical load. The energy balance between load and available solar resource done by PVsyst yielded a feasible and economical system of 100 Kw grid-tie system with a battery bank of 2145 Ah at 48 V. This battery bank was sized to specifically support the critical load sub panel when this system intentionally island during outage. The study obtained an ideal panel orientation as −21 ° tilt angle and 159 ° azimuth angle. The designed system simulated yearly production of 265.21 mWh leading to which a savings of KES 4.3 million per year. This translated to breakeven of 2.7 years for a 100 kW grid-connected system without battery bank while 3.4 years for the same system with batteries. In conclusion, such a system with these savings on electric bills, improved power reliability, and short time of return on investment can be adopted to take advantage of abundant solar energy resources. Therefore, this study recommends a grid connected solar system not only for administration block but to the whole university to take advantage of adequate solar resource within the geographical location. Future work is needed on ways of enhancing energy efficiency and its impact on sizing solar system as alternative power supply.