Optimal integration of hybrid (wind--solar) system with diesel power plant \newline using HOMER

Most energy worldwide is supplied through conventional energy sources, such as thermal, hydro, and nuclear. There have been serious energy crises in the last couple of years and so it is essential to consider renewable energy sources. This paper proposes a cost-effective solution for integrating a wind--solar system with an existing diesel power plant of a grid-connected site at Taxila, Pakistan. In the case of nonavailability of power from the grid, this diesel power plant acts as a standby system. Three cases were considered in this paper: 1) using the diesel power plant during load-shedding hours; 2) assisting the system using renewables when it is connected to the grid (on-grid); 3) completely relying on hybrid energy system to meet the daily load demand if excess energy is available (off-grid). The system was implemented in the software package Hybrid Optimization Model for Electric Renewables (HOMER) developed by the National Renewable Energy Laboratory. Different environmental factors were examined, including wind speeds, solar insolation, and their maximum and minimum differences from the average parameters. In the end, the most optimal solution for each case was proposed to meet the desired load demand while making the system operation economical.