Environmental pollution has been one of the main challenges for sustainable development. Piezoelectric materials can be used as a means of transforming ambient vibrations into electrical energy to power devices. The focus is on an alternative approach to scavenge energy from the environment. This book presents harvesting methodologies to evaluate the potential effectiveness of different techniques and provides an overview of the methods and challenges of harvesting energy using piezoelectric materials. Piezoelectric energy harvesters have many applications, including sensor nodes, wireless communication, microelectromechanical systems, handheld devices, and mobile devices. The book also presents a new approach within piezoelectric energy harvesting using the impact of raindrops. The energy-harvesting model presented is further analyzed for single-unit harvester and an array of multiple harvesters to maximize the efficiency of the device.