ABSTRACT

Wireless sensor networks are infrastructures containing sensing, computing, and communication elements that aim to give its controllers the ability to measure, collect, and react to occurrences in the monitored environment. They can be seen as interfaces between the virtual and the physical worlds. Because of their widespread applications, they are one of the most rapidly developing information technologies. They offer attractive solutions to many environmental, security, and process monitoring problems and promise to revolutionize the way one senses and controls the physical world. However, one barrier to their fuller adoption is the need to supply electrical power over extended periods of time with minimal possible human intervention. Energy harvesting (the process of extracting energy from the surrounding environment) provides a potential solution to this issue. There are various forms of energy options that can be scavenged, such as thermal, mechanical, solar, acoustic, wind, and wave. The present entry reviews a broad range of the ambient energy sources suitable for wireless sensor networks and outlines their characteristics, advantages, disadvantages, and performances. A comprehensive comparison of these sources and conversion mechanisms in terms of their power density is also presented, as well as a rich and updated references included for interested readers.