This book based on an experimental investigation include determination of (power output, monthly average daily energy generation, and efficiency) for the solar module (BP1211SR) at four different tilt angles (0º, 26º, 36º, 46º) in Erbil city (latitude=36º11' N, longitude=44º E, and 430m above sea level), also determining PV area required for demand loads after selecting the best tilt angle for Erbil city. The data has been taken for one year; the data of each month represent the average of (4-5) times in the month taken in three different daytime. The main purpose of this book is how to find the best tilt angle for the solar modules that collect the maximum energy and determine the PV area required for demand loads to select suitable PV system for house and street lighting.