Solar energy has a good potential in several agriculture applications especially in rural and isolated areas and can be considered as a clean substitution fuel instead of fossil fuels. The photovoltaic water pumping system is one of the best alternative irrigation methods. This article presents a procedure for estimating the appropriate size of a photovoltaic system designed to power a pumping system for four irrigation methods (surface, sprinkler, drip, and developed surface irrigation) under different climate conditions for summer of three crops (cotton, thin corn, and soybean) and for winter of three crops (wheat, Bean and Barley). The solar simulation model estimated the hydraulic power, photovoltaic (PV) peak power, PV required area, total system costs and specific water demand according to the type of crop under different irrigation methods in three different geographical locations in Egypt at a different total dynamic head 50,100, and 200 m. As a comparison between the required water demand in several irrigation systems, it is found that the percentage of the amount of water demand per Fadden (m3/F) related to surface irrigation system for summer crops such as cotton crop was 85.7%, 79.9%, 66.7% in developed surface, sprinkler, and drip irrigation respectively. While in case of thin corn crop was 74.3%, 79.9%, 66.7% and for Soybean was 85.7%, 79.9%, 66.6%, respectively. In winter crops, the percentage of the amount of water demand per Fadden (m3/F) related to surface irrigation system for wheat crop was 85.6%, 79.9%, 66.7% and for bean crop was 85.7%, 0.79%, 66.7%, and for Barley crop was 85.7%, 79.9%, 66.6% in developed surface, sprinkler, and drip irrigation respectively