Design, modelling and performance analysis of a residential grid-tied and off-grid solar system

This thesis presents a comprehensive study on the design, simulation, and performance evaluation of residential solar photovoltaic (PV) systems, focusing on both grid-tied and off-grid configurations in the context of Lahore, Pakistan. With the growing energy crisis and increasing electricity tariffs in the region, solar energy offers a promising alternative for reliable and sustainable power generation. The research employs a hybrid methodology integrating techno-economic optimization using HOMER Pro and dynamic performance simulation via MATLAB/Simulink. An 11 kW grid-connected PV system was first analyzed for a residential property in Model Town, Lahore. The system utilized high-efficiency Jinko Solar modules, a DC-DC boost converter, and a Growatt inverter, operating under local climatic and tariff conditions. The analysis revealed a significantly lower Net Present Cost (USD 18,995) and a substantial reduction in grid dependency and carbon emissions, compared to conventional grid-only electricity consumption. In parallel, a detailed dynamic simulation of the same system was conducted in MATLAB/Simulink to study the real-time behavior of the PV setup under varying environmental conditions. The results demonstrated consistent power delivery, effective voltage regulation, and reliable Maximum Power Point Tracking (MPPT) using the Incremental Conductance method, even in the absence of battery storage. Furthermore, the thesis explored the feasibility of a fully autonomous off-grid PV system for the same residential setting. Utilizing HOMER Pro, the off-grid system design included a 12.6 kW solar array, 89 kWh battery storage, and an 11 kW inverter. The simulation results showed excellent economic and technical performance, including a 91% reduction in Net Present Cost compared to diesel-based alternatives, an internal rate of return (IRR) of 228%, and a short payback period of 0.49 years. Additionally, the system produced zero CO2 emissions, reinforcing its environmental benefits. The comparative assessment of grid-tied and off-grid systems provides critical insights into their suitability under different economic, technical, and policy scenarios. The study concludes that both configurations offer viable solutions for residential energy needs, with grid-tied systems being cost-effective under net metering policies, while off-grid systems ensure energy resilience in areas with unreliable grid supply. The findings of this research support the wider deployment of solar PV in urban Pakistan and provide a scalable framework for future implementation and policy development.