Solar energy is the most abundant of the renewable energies, as it is the first and main energy that gives rise to life. This book aims to compare how photovoltaic panels work, demonstrating their construction and studying the effect of cooling on a PV module, as well as analysing the use of solar energy in a single module, a hybrid solar collector (photovoltaic and thermal). The concept of converting solar energy into electricity and heat was explained. In photovoltaic generation, efficiency is directly linked to operating conditions such as incident solar radiation, construction model and operating temperature.