Solar energy development trends and climate impacts on its performance in Iran: A comparative analysis

This study provides a comprehensive analysis of the development trend of renewable energy and solar photovoltaic (PV) systems in Iran and assesses the impact of climate variability on the performance of photovoltaic systems in the four main climatic regions of the country. The innovation lies in an integrated approach that combines national trend analysis with standard PVsyst simulations for four sample climates and separates the net climatic effects (temperature, humidity, radiation) on energy efficiency and performance ratio (PR) through controlled technical parameters. The main objective is to shed light on renewable energy growth, environmental benefits, and climate-specific optimization strategies to guide targeted policymaking and sustainable development. The methodology of this study is based on the study and analysis of real historical data and the use of PVsyst simulation software. The main evaluated parameters include Produced Energy, Performance Ratio (PR), ambient temperature, and EArray. Results reveal steady renewable share growth from 0.07% in 2016 to 0.9% in 2025 despite low overall contribution (total renewable capacity exceeding 1,966 MW, with solar at ∼1,782 MW), significant resource savings including 4,472 million m³ natural gas and 3,557 million liters of water, and another result of this study showed that climatic trade-offs: hot-dry zones like Yazd yield highest energy (2.28 million kWh/year) but lower PR (87.55%) due to temperature penalties, while mild-wet areas like Rasht exhibit superior efficiency (PR 91.11%) despite lower output (1.48 million kWh/year), underscoring the need for region-tailored designs to maximize Iran's solar potential. These results indicate that, under the conditions of this study, areas with higher irradiance showed higher electricity generation, while milder climatic conditions were associated with better relative system performance.